李旭
, 蔡进功, 宋明水
Li Xu, Cai Jingong, Song Mingshui
中图分类号: P618.12
文献标识码: A
文章编号: 1001-8166(2018)05-0493-13
通讯作者:
收稿日期: 2017-12-15
修回日期: 2018-03-24
网络出版日期: 2018-05-20
版权声明: 2018 地球科学进展 编辑部
基金资助:
作者简介:
First author:Li Xu(1992-),male,Xuzhou City,Jiangsu Province,Ph.D student. Research areas include shale pore structure characteristics and shale oil and gas evaluation. E-mail:lixu_0424@tongji.edu.cn
作者简介:李旭(1992-),男,江苏徐州人,博士研究生,主要从事泥页岩孔隙结构特征与页岩油气评价研究.E-mail:lixu_0424@tongji.edu.cn
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摘要
泥页岩中残留烃具有多种赋存态,且赋存态与赋存空间紧密相关,残留烃的研究必须同时关注赋存态和赋存空间。残留烃的不同赋存态在本质上是由于残留烃组分以及孔隙和表面性质的多样性造成的,导致不同赋存态烃的剥离条件具有差异,基于这种差异,提出有机溶剂抽提—化学湿氧化的相继处理方法分离游离态烃、物理吸附烃和化学结合态烃。泥页岩中存在多种类型的孔隙和表面,气体吸附法、压汞法、化学吸附法和成像方法的配合才能够全面表征泥页岩的孔隙结构。通过分析每一步处理前后烃参数和孔隙结构表征参数的变化特征可以建立烃—孔隙表面的关系,而烃和矿物在分子层面和微观尺度相互作用的研究有助于进一步丰富烃—孔隙—表面的关系,这对于深刻理解残留烃的赋存机理和流动特征具有重要意义。
关键词：
Abstract
Development of shale oil and gas has prompted people to think about the occurrence space and occurrence states of residual hydrocarbon in shale. There are three occurrence states of residual hydrocarbon in shale: free, adsorbed and dissolved. The contribution of different state hydrocarbon remains uncertain. The occurrence space for hydrocarbon includes pore and surface. Pore can be divided into macropore, mesopore, micropore; and surface can be distinguished between the external and internal surface. Filling and adsorption of hydrocarbon in/on different spaces vary a lot. Furthermore, characteristics of hydrocarbon and organic matter, and the burial and evolution process could complicate the relationships among hydrocarbon, pore and surface. In summary, research on residual hydrocarbon in shale must focus on occurrence state and space simultaneously. Rock-Eval pyrolysis and organic solvent extraction are effective quantitative methods for residual hydrocarbon evaluation, and calibration of characteristic parameters is of great significance. Union of N2 adsorption, mercury intrusion and EGME adsorption methods could achieve the pore structure characteristics of shale comprehensively. These quantitative evaluation methods are the basis for the research on relationships among hydrocarbon, pore and surface. This paper recommended progressively use of organic solvents and wet chemical oxidation methods which can separate free hydrocarbon, physical adsorption hydrocarbon and chemical bonding hydrocarbon gradually, and then we could establish the relationship among hydrocarbon, pore and surface by the combination of residual hydrocarbon and space quantitative characterization methods. Research on the interactions between hydrocarbon and minerals in molecular level and micro-scale will enrich the relationship among hydrocarbon, pore and surface, and it has great significance for us to understand the occurrence mechanism and flow characteristics of residual hydrocarbon in shale.
Keywords：
页岩油气的发现促使人们思索泥页岩中残留烃(油气)的赋存空间以及赋存方式等特征,这对深入认识该类油气藏油气赋存机理以及资源评价都具有重要意义。在国内外广泛发现页岩油气,如美国的Barnett,Bakken和Eagle Fort等页岩层系[1,2,3,4];我国的四川盆地下古生界[5]、鄂尔多斯盆地延长组[6]、渤海湾盆地济阳坳陷沙河街组[7,8,9,10,11]、松辽盆地青山口组[12]和南襄盆地泌阳凹陷核桃园组[13]等。对已发现页岩油气藏的研究表明,页岩油气藏属于非常规油气藏,液气态烃呈“源内分散状态”赋存,是一类低丰度连续性的自生自储性油气藏[14,15,16,17]。从油气运移的角度来看,页岩油气藏属于油气生成后滞留于生烃层的烃—残留烃(油气)构成的油气藏[18,19]。页岩油气藏中烃的赋存空间(纳米孔隙、有机质孔和表面等)及赋存方式(游离、溶解和吸附等)都具有特殊性[20],与常规油气藏具有明显的差异性。因此,页岩油气藏的研究思路、检测方法、资源评价和勘探开发对策等必然与常规油气有着巨大的差异,这引起了石油地质研究者的广泛重视。
页岩中的烃以游离、吸附和溶解等3种方式赋存,研究发现含气页岩中吸附气含量可达20%~85%[21,22,23];页岩油以游离或吸附态赋存为主,溶解态为辅[1,24],充分展现了烃赋存方式的多样性和不确定性。前人研究发现,烃的赋存方式与赋存空间相关,页岩的赋存空间包括孔隙和表面,其中游离烃与孔隙有关,吸附烃与表面有关[25,26,27],即烃赋存方式与赋存空间类型关系密切。进一步的研究将泥页岩中游离烃富集的主要场所——孔隙,分为大孔、介孔和微孔[28],不同尺寸的孔隙具有不同的充填特征[29];比表面包括内表面和外表面,一般来说外表面包括所有的突出部分和缝隙开口宽度大于缝隙深度的孔隙表面,内表面则是缝隙开口宽度小于缝隙深度的孔隙表面[28],不同表面上烃吸附的方式存在差异,如外表面主要是物理吸附,而内表面主要是化学吸附等[30,31]。有机质性质的差异也会影响烃的赋存方式,如III型有机质、高成熟度有机质具有更强的吸附能力[23,32],无定形有机质具有更强的溶解能力[33]等,并且溶胀作用的存在还会增加可供物理结合的比表面积[1],这些都展现了泥页岩中烃赋存方式与赋存空间的差异性。泥页岩中的油气包括饱和烃、芳烃、非烃和沥青质等,不同组分的化学性质不同,如非烃中O,N和S等原子增强了其化学活性等;烃又有轻质烃和重质烃之分,不同分子量烃分子与表面的吸附性质存在差异[34]。由此看来,泥页岩中烃赋存空间、赋存方式以及烃的特性等复杂且多变,这将会对泥页岩中残留烃等特征的研究带来极大的挑战。
石油地质学研究常采用有机溶剂抽提(氯仿沥青“A”)或热解检测(S1和S2等)等方法揭示油气或烃的特征,这也是页岩油气研究中常采用的方法手段[35,36]。在有机质的研究中,可采用有机溶剂抽提方法获取烃源岩中的可溶有机质与族组分,不同极性的有机溶剂所得到的可溶有机质的数量及组成差异极大[37,38],表明可溶有机质的剥离条件存在差异。随着对表层沉积物、土壤以及泥页岩中有机质赋存多样性的深刻认识,前人采用双氧水、次氯酸钠和过硫酸钠等化学氧化剂方法,解析化学吸附或层间赋存的有机质[39],甚至采用了有机质溶剂抽提—皂化—酸解连用的方法,逐次探讨有机质在沉积物及岩石中的赋存特征[40],这些研究为我们开展泥页岩中烃赋存特征的研究提供了很好的借鉴。
本文通过总结前人对泥页岩残留烃表征、残留烃的不同赋存态以及泥页岩或土壤中有机质的分离、孔隙结构和比表面的表征等方面的研究成果,探讨烃—孔隙—表面的关系研究对泥页岩中残留烃赋存机理及其有效表征的重要意义,同时提出一种进行烃—孔隙—表面关系研究的思路,以期为页岩油气的勘探开发提供理论基础和科学依据。
2.1.1 残留烃量的表征
页岩油气研究的关键,首先是残留烃量的表征,目前,泥页岩残留烃量表征的常用手段有热解检测和氯仿抽提,可分别得到S1和S2以及氯仿沥青“A”和族组分等参数,能直观反映页岩油气含量及变化等特征[35,36]。
热解检测可以获得S1和S2等烃参数[41,42,43]:S1是在300 ℃以前通过热挥发作用得到的烃,通常被认为是残留烃[18]或游离烃[1,36,44];S2被认为是干酪根热裂解生产的烃,反映烃源岩现今的生烃潜力[41]。前人利用S1和S2恢复烃源岩的原始生烃潜量,并利用热解参数演化剖面开展生排烃模式[18,45~47]以及页岩油聚集特征[19]研究。氯仿沥青“A”是用有机溶剂,如氯仿或二氯甲烷等,进行索氏抽提得到的可溶有机质,利用层析原理可以得到饱和烃、芳烃、非烃和沥青质等组分,并可利用氯仿沥青“A”/总有机碳(Total Organic Carbon,TOC)的剖面演化特征拟合残烃率曲线,进而求取烃源岩的残烃率[46]。
对比热解烃参数和氯仿沥青“A”的检测原理,可知热解烃与氯仿抽提物组分既有重叠又有差异[48],这可以由氯仿沥青“A”与热解S1之间良好的相关性[49]以及泥页岩黏粒级组分抽提前后热解S1和S2不同程度的变化[50]证明。热解参数与氯仿沥青“A”的色谱分析表明,热解S1与氯仿抽提物中饱和烃的碳数存在重合也存在差异,此外,氯仿抽提物中的非烃、沥青质等组分的热裂解构成了S2的主要来源,这也说明了热解和氯仿抽提方法在表征残留烃方面的重叠与差异性[51,52]。但是,泥页岩既有气态烃(C1~C4)、轻质烃(C5~C14)和重质烃(C15+),也有非烃和沥青质,各类烃性质的差异决定了赋存方式与稳定性的差异,热解检测与有机溶剂抽提得到的烃参数极易丢失轻质烃,同时难以获取烃赋存方式的信息,因此,校正烃参数和改进检测程序具有重要意义。
2.1.2 残留烃量表征参数的校正
烃参数检测过程中的轻质烃散失对烃源岩及泥页岩残留烃评价的影响早已引起研究人员的注意[1,44,53~57]。Cooles等[58]研究认为热解S1的轻质烃损失量受到有机质丰度、岩相、石油的品质和样品保存条件的影响;前人研究了泥页岩粉末的保存时间对热解S1及饱和烃组分的影响,结果表明:C10-的烃明显散失,热解S1明显减小,热解S2基本恒定,并且高有机质丰度可能会抑制轻质烃的散失[59,60]。热解S1的滞留效应同样不可忽视,其可能原因是与有机质相关的孤立孔隙中滞留的烃或结合更稳定的烃只有在更高的温度下才能被洗脱出来[1,61]。因此,应用残留烃量表征参数时进行轻重质烃组分的恢复才能达到更好的评价效果。
前人建立了2类轻重质烃恢复系数计算方法,一类是通过分析不同保存条件下样品的烃参数、抽提前后的热解参数以及自生自储油气藏中原油与烃源岩氯仿抽提物组分的差异[56],或利用低温密闭氟利昂抽提等方法[62,63],获取轻重质烃含量或比例系数,进而计算热解S1的轻质烃恢复系数、S2中的滞留烃比例系数以及氯仿沥青“A”的轻质烃恢复系数;另一类则是基于岩石与原油的热模拟实验,结合有机质全组分生烃动力学方法,计算氯仿沥青“A”和热解S1的恢复系数[57]。这些方法对样品的采集、保存和实验条件要求较高。
页岩油气赋存的孔隙空间存在巨大的差异。首先,泥页岩中发育多种类型的孔隙:①国际纯粹与应用化学联合会(International Union of Pure and Applied Chemistry,IUPAC)依据孔径大小、吸附性质和毛细管凝聚现象将孔隙分为微孔(<2 nm)、介孔(2~50 nm)和大孔(>50 nm)[28],其中,微孔对物理吸附和化学吸附具有重要的贡献,而介孔和大孔则可以发挥储集和输运体系的作用[29,30];此外,纳米孔隙特殊的尺寸效应和表面效应会显著影响孔内流体的动力学行为,从而对地球化学反应和物质迁移产生重要影响[64]。②从孔隙成因角度看,泥页岩中发育有矿物基质孔、有机质孔和裂缝孔,不同成因的孔隙性质存在差异,如:黏土矿物层间、黏土矿物小片间、黏土矿物聚集体间的孔隙以及有机质孔的孔径不同[65,66,67]。③孔隙成因类型、孔隙度、孔径分布等随着埋藏演化过程不断变化[61,68],如随着成熟度的增加,富有机质页岩中开始出现大量的有机质孔[68,69,70,71,72],孔隙度在埋藏过程中通常会出现减小—一定的增加—再次减小的演化过程[73];由于较小孔径的孔隙具有更高的弹性屈曲压力,因此,随着埋藏演化过程的深入,纳米孔隙将扮演更重要的角色[66]。通过上述分析可见,泥页岩的孔隙空间的构成非常复杂,并且孔隙类型、孔隙度、孔径分布是一个动态演化的过程,因此,分离不同类型的孔隙空间,并分别研究其演化过程及在烃赋存中的作用,对残留烃赋存特征的研究具有重要意义。
分子动力学研究表明泥页岩中表面附近烃的富集程度高且流动性差[34,74,75],不同性质的表面对残留烃赋存的影响也具有差异,进而对纳米孔隙中资源量评价造成显著影响,因此,对表面和烃关系的研究具有重要意义。泥页岩中的表面分为内表面和外表面,前人通过对比原样、二氯甲烷抽提后样品和次氯酸钠氧化后样品的傅里叶红外光谱谱峰,结合二氯甲烷以及次氯酸钠的化学属性[30,31],认为外表面对烃的吸附主要以物理吸附为主,而内表面以化学吸附为主[30],化学吸附的有机质和烃更加稳定且具有选择性[76,77]。从比表面积及其吸附性质的影响因素看:①黏土矿物对比表面的贡献最大,其中蒙脱石的内表面最为丰富,从而具有比伊利石、高岭石更强的吸附能力[78,79,80,81]。②有机质相较于黏土矿物具有更强的吸附能力[81,82],且不同类型有机质对比表面的贡献也有差异,III型有机质通常具有更大的比表面积[32]。从演化的角度来看,内外表面的演化过程也存在差异[30],这会影响不同演化阶段残留烃不同赋存态的相对比例。总之,表面性质以及演化过程的差异造成了不同类型表面与有机质或烃之间关系的差异[83],对这种差异性及其机理的研究有助于残留烃的有效评价。
综合以上分析可知,泥页岩烃赋存空间具有极大的差异性,而这种差异性将会对烃的赋存方式产生影响,如造成物理吸附与化学吸附等,并进而造成烃赋存稳定性的差异,因此,在泥页岩残留烃的研究中必须关注赋存空间与烃赋存方式间的关系,这对深入认识泥页岩残留烃的特征极其重要。
页岩中烃有不同的赋存态,其中以游离和吸附态为主,从赋存态与赋存空间的关系看,游离烃赋存于孔隙中,吸附烃赋存于表面上。传统的热解程序难以达到表征不同赋存态烃的目的,通过对泥页岩的热解检测深入研究,前人对热解参数进行了精细解析:矿物基质的吸附作用会对热解参数产生影响,通过分析热解S2-TOC交会图,Langford[84],Dahl等[85]和Erik等[86]建立了图解法分析矿物基质吸附烃的方法,但是机理并不明确;考虑到重质烃和胶质、沥青质等的降解会对S2有贡献,Delvaux等[87]提出对比抽提前后热解曲线来求取可溶有机质的热解曲线的方法,这一分析程序近年来被用于估算页岩油储层的总油含量[1,52];Sanei等[51]则通过改进热解程序将S1和S2峰分为S1ESH,S2aESH和S2bESH,进一步的热解—色谱分析表明全岩或黏粒级组分在热解的不同温度段释放出来的烃的组分不同[51,88]。综合上述分析,发现无论是哪种方法,其基本思想都是将S1或S2按照不同赋存态的性质差异等分成多个部分,这充分反映了页岩油气组分、赋存方式、稳定性等的复杂性,传统的检测方法对深入认识残留烃的赋存特征存在不足。
泥页岩中黏粒级组分抽提前后不仅热解参数在变化,其比表面性质也发生变化[50],对泥页岩全岩利用不同有机溶剂相继抽提后发现抽提物的量、组分以及孔隙结构都相继发生变化[25]。页岩高压甲烷吸附模拟研究表明TOC含量、热成熟度、黏土矿物、湿度、孔隙性质、粒径、温度和压力都会对甲烷吸附能力造成影响[89,90,91],并且不同类型的有机质或黏土矿物也具有不同的吸附能力[32,80],纳米孔隙流体中的离子特征也会显著影响流体的流动和排出性质[92],这都是表面性质的差异导致的。因此,泥页岩中有机质和烃与赋存空间(孔隙、表面、有机质等)紧密相关,改进的热解检测方法虽然可以分离检测不同赋存态或赋存稳定性的烃,但是无法得到赋存位置信息,无法全面认识页岩油气赋存特征。
有机质的类型会影响其在泥页岩中的赋存位置和赋存方式[93],而泥页岩中的烃也有着轻质烃、重质烃、非烃之分,不同类型烃的化学活性和物理活性均存在差异,如轻质烃在保存过程中会很快散失[60],因此,烃的性质也会显著影响其在泥页岩中的赋存方式和稳定性。气页岩和纯矿物中的气体吸附模拟实验表明,不同类型气体的吸附能力存在差异[94];分子动力学研究表明,纳米孔隙中油的分布可以区分出密度明显不同的吸附层和游离相,其中重质组分表现出更强的吸附能力[34]。综合以上分析,在泥页岩残留烃的赋存特征及赋存机理的研究中,对不同赋存态烃性质的研究也是一个重要方面。
近年来,研究人员已经认识到残留烃赋存态研究的重要性,而残留烃不同赋存态在本质上是由于赋存空间(孔隙和表面)性质以及烃性质的差异导致的,因此,如何分离不同赋存态的烃,并探讨烃—孔隙—表面之间的关系,对深入理解页岩油气的赋存机理具有重要意义。
上述分析表明页岩油气赋存于孔隙和表面上,不同类型孔隙和表面上赋存的烃的性质及其稳定性存在差异[34,75],据此可进行不同赋存态烃的分离。
有机溶剂抽提是石油地质学研究中常用的提取可溶有机质的方法,不同类型有机溶剂可以实现不同结合强度有机质的分离[37];宋一涛等[38]在研究烃源岩中2种赋存态可溶有机质特征时,将氯仿和甲醇—丙酮—氯仿(Methanol-Acetone-Chloroform,MAC)三元试剂相继抽提获得的可溶有机质作为游离和物理吸附态可溶有机质,而抽提后固体去除无机矿物后进行相继抽提,再加上无机矿物去除过程中加入的酸液中的有机质作为结合态可溶有机质,不过这一程序具有破坏性。二氯甲烷是常用的抽提剂,抽提后的页岩保持了原有孔隙结构特征[95],是良好的用于游离态和结合较弱的物理吸附态有机质和烃分离的方法,但是溶剂抽提法对化学吸附态烃的分离效果不好。
化学氧化方法因其更高的有机质去除效率而更广泛地用于有机质赋存与保存机制和富有机质泥页岩孔隙结构的研究。Robinson[96,97],Anderson[98]和Meier等[99]分别提出利用过氧化氢、次氯酸钠、过硫酸钠作为氧化剂去除泥页岩和土壤中的有机质;由于这3类氧化剂氧化性存在差异,其处理效率也存在差异,总的来说有机质去除效率为过硫酸钠>次氯酸钠>过氧化氢[39]。由于化学氧化方法破坏的是有机质和烃与矿物之间的化学键,可以分离化学吸附态的烃和有机质,但是化学氧化剂较强的氧化性不可避免地会对泥页岩矿物结构造成一定的破坏,如过氧化氢湿处理或干燥过程都会通过烧结小的孔隙或矿物转变等降低含水金属氧化物的比表面[100];硫铁矿常用来促进过硫酸钠产生硫酸根自由基以提高氧化活性,在此过程中硫铁矿被氧化[101,102]。次氯酸钠处理前后矿物成分对比表明硫铁矿也存在一定量的破坏,但是这种破坏相对较弱[66],因此,推荐用于硫铁矿含量较高的样品。还有学者对有机溶剂抽提后或次氯酸钠处理后的样品进行碱解或直接利用HCl和HF完全溶解矿物获取残留下来的更为稳定或赋存于封闭孔隙空间中的有机质和烃[40,103,104],但是这种方法破坏了矿物基质孔和矿物表面,不利于进行烃—孔隙—表面关系的研究。热处理方法也常用于土壤和沉积物小的介孔中有机质的去除,其效率一般高于氧化方法[105,106],但是该方法对矿物的破坏情况尚缺乏研究,在使用时需要慎重。
综合以上分析,泥页岩中残留烃具有游离态、物理吸附态和化学吸附态等,单独利用有机溶剂抽提或化学氧化方法都难以达到逐次分离不同赋存态烃的目的,前人研究表明,相继处理是有效的分离方法[25,38,39,107]。因此,建议采用下列程序逐次分离不同赋存态的烃和有机质:首先选用弱极性的有机溶剂(二氯甲烷)对泥页岩样品进行抽提以去除其中游离态和部分物理吸附态的烃;抽提后的固体残渣用次氯酸钠在常温条件下控制溶液初始pH值为8进行有机质的去除[39,106],该过程可以去除强物理吸附态和较弱化学结合态的烃。相继处理过程分离不同赋存态烃和有机质的原因和依据如下:
二氯甲烷属于弱极性有机溶剂,其对样品的处理主要是通过相似相溶原理,克服的是分子间相互作用力,前人的研究表明二氯甲烷抽提后外表面积显著增加,孔径分布特征显著变化;此外,采用不同的弱极性有机溶剂获取的物质量和组分不同,外表面积及孔径分布特征也会进一步改变[25,30,31,37,38];据此认为抽提过程主要分离游离态烃和部分物理吸附态的烃。次氯酸钠是一种氧化剂,可以破坏化学键,次氯酸钠氧化后内表面积显著增加,并且氧化过程中TOC的变化与内表面积的变化具有更好的相关性[31];此外,不同类型的氧化剂的处理效率不同,且次氯酸钠氧化后仍残留有一定量的有机质[31,39,103];因此认为氧化过程主要分离抽提后仍残留的较强物理吸附态烃及较弱化学结合态的烃。
泥页岩中烃的赋存空间包括孔隙和表面,为此,如何有效地表征孔隙和比表面至关重要。孔隙覆盖大孔、介孔和微孔范围,表面也有内外表面之分,因此,定量化的全表征赋存空间至关重要。压汞法、吸附法、Water Immersion Porosimetry(WIP)、Small-angle and Ultra-Small-Angle Neutron Scattering(SANS/USANS)、Scanning Electron Microscope(SEM)、Focused Ion Beam-Field Emission Scanning Electron Microscopy(FIB-FESEM)、Transmission Electron Microscope(TEM)、Atomic Force Microscope(AFM)、Nuclear Magnetic Resonance(NMR)、nm-Computerized Tomography(nm-CT)和乙二醇乙醚(Ethylene Glycol Nonomethyl Ether,EGME)化学吸附法等众多检测手段为孔隙度、孔径分布、比表面积和孔隙形态等的定量或定性表征提供了基础[20,29,30,65,67,70,71,108~114]。
3.2.1 孔隙表征
页岩油气藏中孔径分布跨度大,如何全面、定量地表征是关键。压汞法和气体吸附法是最常用的定量表征多孔介质孔隙结构的方法。非润湿流体进入孔隙中所需克服的毛细管力与孔径之间存在定量关系(Washburn方程),压汞毛细管压力测试法就是基于该原理,压汞法可以获取3 nm~123 μm的孔径分布信息,但在较高和较低的压力范围内存在较大误差[65,71,110,112]。气体在孔隙内的物理充填过程大体上可以分为微孔充填阶段、单层—多层吸附阶段和毛细管凝聚阶段[28],气体吸附量与相对压力之间存在定量关系,气体吸附法即是基于BJH,D-R,D-H,H-K,S-F,∝s,NL-DFT和分子动力学模拟等方法和模型计算多孔介质的孔径分布、比表面等[29,115~120],该方法适用于0.35~300 nm的孔隙测量,对微孔和介孔更有效[65,112]。上述分析表明压汞法和气体吸附法都无法独立、准确描述泥页岩的全孔径分布特征,因此,研究人员尝试联用压汞法和气体吸附法[29,112,121,122],并对合理接合孔径点的选取进行了探索,如Echeverría等[29]基于微孔充填理论、Kelvin方程和Washburn方程分别适用于0.5~2 nm,2~7.5 nm和大于7.5 nm孔径范围的孔隙,将2 nm和7.5 nm作为接合点;Schmitt等[112]则以毛细管凝聚阶段液氮充填量与进汞量相等的孔径作为接合点。必须注意的是压汞法主要受到孔隙喉道的控制,气体吸附法则主要受孔体本身的控制,二者所得的孔体积并不能直接对比[66],因此,无论利用什么方法接合两部分孔径分布曲线都只能是对全孔径分布的近似,但是,这种近似所反映的孔径分布趋势并没有改变。通过对比有机溶剂抽提和化学氧化处理前后泥页岩全孔径分布的变化特征,即可研究不同赋存态的有机质或烃的赋存位置信息,进而建立残留烃与孔隙间的关系。
孔隙度和孔隙形态的表征也是泥页岩孔隙结构特征研究的重要方面。孔隙度可以通过汞浸润法—He测比重法或水浸法获得[66,71],是进行资源量估算的重要参数。SEM,TEM和CT扫描等成像方法是常用的进行表面微观形貌定性分析的手段,利用聚焦离子束(Focused Ion Beam,FIB)磨制平坦的表面可以将观测精度提高到4~7 nm,但存在微孔表征以及难以获取统计有效的孔径分布定量结果等缺陷[66,71]。近年来得到快速发展的NMR方法不仅可以获取泥页岩的全孔径分布信息,还能够对孔隙流体的流动特性进行分析,具有良好的应用前景[110,123]。依据形态特征可将气体吸附—脱附等温线分为6类吸附曲线和4类脱附回滞环,曲线形态类型包含着物理吸附过程机制信息,可用于孔隙形态类型的定性分析[28,66,112];烃去除前后富有机质页岩吸附—脱附曲线形态的差异[67]表明烃的赋存改变了泥页岩的孔隙结构,因此,分析不同赋存态烃剥离后的孔隙结构信息更有意义。
3.2.2 比表面表征
泥页岩的比表面对烃尤其是液态烃的赋存及分布特征有重要影响,还对孔隙中流体的性质及流动特征具有重要的控制作用[34,75,92]。气体吸附法、化学吸附法、原子力显微镜方法、水分子吸附法、亚甲基蓝吸附法、压汞法等可用于表面积的测量[112, 124~126]。
简单气体分子(N2)吸附法求取表面积是基于多分子层吸附(Brunauer-Emmett-Teller, BET)理论,而多分子层吸附理论就是建立在物理吸附的基础上[127],因此所得的表面积通常代表外比表面积;压汞法也可以通过相应的计算模型获得外比表面积,由于缺乏对表面积贡献大的微孔的测量,其结果通常小于BET比表面积[112]。EGME化学吸附法是常用的测量总比表面积的方法,基于EGME达到吸附平衡时的转换因子(2.86×10-4 g/m2),利用平衡吸附时的吸附量就可以计算总比表面积[124,125,128,129]。EGME化学吸附法所得的总比表面积与N2吸附法获得的BET外比表面积的差值即可代表内比表面积[68,128]。原子力显微镜可以更细致地将表面积分为外表面积、边缘表面积和基底表面积[108],但由于其分析颗粒数量的局限性以及泥页岩矿物组成的复杂性,限制了其在定量表征泥页岩比表面积中的应用。有机溶剂抽提法和化学氧化法等处理后的泥页岩样品的表面积会发生变化[50],通过对这种变化的表征即可建立不同赋存态烃或有机质与泥页岩比表面之间的关系。除了比表面积之外,表面的微观属性(润湿性、电性)也会对残留烃的赋存与流动造成重要影响[92],这将是表面性质表征重要的发展方向之一。
泥页岩中存在不同类型的孔隙和表面,其对孔隙中和表面上流体的分布和流动特征具有重要的控制作用,页岩油气储层的全孔径分布以及不同类型表面的定量表征是进行孔隙—表面—烃关系研究的关键,因此,泥页岩储层的表征应当抓住定量化和全面化2个核心。
泥页岩中残留烃赋存态是残留烃与赋存空间(孔隙和表面)相互作用的结果,本质上受残留烃性质和赋存空间性质控制,残留烃的研究必须同时关注赋存态和赋存空间。而传统的热解检测和有机溶剂抽提方法不能实现不同赋存态烃的分离,同时还缺乏对赋存空间的表征;传统的孔隙结构检测手段得到的是有机质和烃充填或覆盖后的状态,并不能准确表征有机质和烃的赋存信息。前人常通过对比不同处理方法(有机溶剂抽提、化学氧化、热处理等)处理前后有机质或烃参数、孔隙结构和比表面积表征参数的差异来分析泥页岩中有机质和烃的赋存与分布特征[31,50,105,106,130];更进一步的,研究人员通过分析不同极性有机溶剂相继抽提后泥页岩孔隙结构和比表面的变化来研究不同类型孔隙对烃和有机质赋存的贡献[25,107]。上述分析表明,选用合理的处理程序可以实现分离检测不同赋存态的烃,结合全面而定量的孔隙和比表面表征手段,可以建立不同赋存态的烃与孔隙和表面之间的响应关系。本文提出的有机溶剂抽提—化学湿氧化相继处理方法可以同时实现物理结合态和化学结合态烃和有机质的分离,能够更加全面地分析不同赋存态烃与赋存空间之间的关系。
页岩油气资源评价的关键问题之一是资源量尤其是可动资源量的计算。目前,研究人员主要通过经验统计、理论模型计算、模拟实验等方法进行探索[1,6,54,57,62,131,132],但这些方法简单地将吸附烃作为不可动烃,且缺乏对可动烃赋存位置及其影响因素的研究;因此,可动资源量评价应当区分出不同赋存态烃的贡献[34,89]。考虑到孔隙和表面的性质影响着残留烃的赋存态及其流动特征[25,67,75,107,133],因此,通过建立烃—孔隙—表面的关系,可以从不同赋存位置上残留烃的稳定性角度,解决可动资源量计算的问题,并对不同赋存位置上烃的可动条件进行分析[31],这对于合理选取提高油气采收率(Enhance Oil Recovery,EOR)方法具有重要意义。由于本质上残留烃的可动性受到赋存空间微观性质(表面润湿性、电性等)和残留烃性质(组分、极性等)的控制,因此,应该从微观角度对残留烃—孔隙—表面的关系进行研究,更多地关注不同类型赋存空间中赋存烃的性质和稳定性以及表面微观性质等的改变对不同组分残留烃分布及其稳定性的影响,从而对残留烃的赋存机理形成更深刻的认识。
综合以上分析,结合有机溶剂抽提法、化学氧化法、孔隙结构与比表面表征方法、热解检测方法和热解色谱等分析方法,可以解析不同赋存态或不同稳定性的烃及其与赋存空间关系,这对于深刻认识残留烃赋存机理、残留烃可动性评价以及合理的选取EOR方法都具有重要意义。
页岩油气的大规模勘探开发挑战了常规石油地质理论,目前对于页岩油气富集机理及其流动机理的研究已经滞后于工业开发,对页岩中赋存烃量尤其是可动烃量的评价仍然是一个难题。通过总结前人研究成果得出以下认识:
(1) 热解和氯仿抽提是页岩油气资源量评价最直接、最有效的方法,二者既有相关性也存在差异;如何校正和恢复地层条件下残留烃量具有更重要的意义。
(2)泥页岩中多种类型和性质的孔隙和表面造就了残留烃的多种赋存态,孔隙和表面的埋藏演化造成不同赋存态烃相对含量的动态演化,从而增加页岩油气资源量及其可动性评价的难度,因此对不同性质赋存空间上不同组分烃的赋存机理和赋存特征的研究具有重要意义。
(3)有机溶剂抽提—化学湿氧化相继处理方法可以达到分离不同赋存态有机质和烃的目的,通过对比处理前后孔隙、表面和烃参数的差异可以建立不同赋存态烃与赋存空间的关系,进而可以更深入的分析有机质含量、类型、热演化程度和岩相等对页岩油气富集的影响,丰富页岩油气富集机理并为页岩油气勘探开发提供理论指导。
致 谢:胜利油田对本研究提供了采样、资料收集等支持,朱晓军、曾翔等在本文撰写过程中提出建设性意见,审稿人提出了中肯的修改意见,在此对他们表示诚挚的感谢!
The authors have declared that no competing interests exist.
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Shale resource systems for oil and gas: Part 2—Shale-oil resource systems [J].
ABSTRACT S hale resource systems have had a dramatic impact on the supply of oil and especially gas in North America, in fact, making the United States energy independent in natural gas reserves. These shale resource systems are typi-cally organic-rich mudstones that serve as both source and reservoir rock or source petroleum found in juxtaposed organic-lean facies. Success in producing gas and oil from these typically ultra-low-permeability (nanodarcys) and low-porosity (<15%) reservoirs has resulted in a worldwide exploration effort to locate and pro-duce these resource systems. Successful development of shale-gas resource systems can potentially provide a long-term energy supply in the United States with the cleanest and lowest carbon dioxide-emitting carbon-based energy source. Shale-gas resource systems vary considerably system to system, yet do share some commonalities with the best systems, which are, to date, marine shales with good to excellent total organic carbon (TOC) values, gas window thermal matu-rity, mixed organic-rich and organic-lean lithofacies, and brittle rock fabric. A general classification scheme for these systems includes gas type, organic richness, thermal maturity, and juxtaposition of organic-lean, nonclay lithofacies. Such a classification scheme is very basic, having four continuous shale-gas resource types: (1) biogenic systems, (2) organic-rich mudstone systems at low thermal maturity, (3) organic-rich mudstone systems at a high thermal maturity, and (4) hybrid systems that contain juxtaposed source and nonsource intervals. Three types of porosity generally exist in these systems: matrix porosity, organic porosity derived from decomposition of organic matter, and fracture po-rosity. However, fracture porosity has not proven to be an important storage mechanism in thermogenic shale-gas resource systems. To predict accurately the actual resource potential, the determination of orig-inal hydrogen and organic carbon contents is necessary. This has been a cumber-some task that is simplified by the use of a graphic routine and frequency distri-bution (P50) hydrogen index in the absence of immature source rocks or data sets. 1鈥揚art 1 Jarvie, D. M., 2012, Shale resource systems for oil and gas: Part 1 鈥 Shale-gas resource systems, in J. A. Breyer, ed., Shale reservoirs 鈥 Giant resources for the 21st century: AAPG Memoir 97, p. 69 鈥 87.
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From tight oil & gas to shale oil & gas—An approach to developing unconventional oil & gas in China [J].从致密油气到页岩油气——中国非常规油气发展之路探析 [J]. |
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Shale oil development may change the landscape in the world’s oil market [J].页岩油开发可能改变世界石油形势 [J]. |
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Progress and prospects of shale gas exploration and development in China [J].中国页岩气勘探开发进展与发展前景 [J]. |
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Characteristics and resource prospects of tight oil and shale oil in Ordos basin [J].鄂尔多斯盆地致密油、页岩油特征及资源潜力 [J].
长庆油田对渗透率为0.3～1 mD的超低渗透油藏已实现了规模有效开发。考虑到鄂尔多斯盆地石油勘探开发实际,将储集层地面空气渗透率小于0.3 mD,赋存于油页岩及其互层共生的致密砂岩储层中,石油未经过大规模长距离运移的油藏称为致密油,包括致密砂岩油和页岩油2大类。延长组致密油主要发育于半深湖—深湖相区,以延长组7段(简称长7)油层组油页岩、致密砂岩和湖盆中部的延长组6段(简称长6)油层组致密砂岩最为典型。致密油具有分布范围广,烃源岩条件优越,砂岩储层致密,孔喉结构复杂,物性差,含油饱和度高,原油性质好,油藏压力系数低的特点。纳米级孔喉系统广泛发育是致密油储集体连续油气聚集的根本特征,延长组致密砂岩储层中大多数连通的孔喉直径大于临界孔喉直径,满足油气在致密储层中运移的条件。根据致密油层与生油岩层的接触关系,确定了3种致密油储集层类型:①致密块状砂岩储层;②砂岩-泥岩互层型储层;③油页岩型致密储层。鄂尔多斯盆地长6和长7油层组致密油分布广泛,初步预测致密油总资源量约30×108t,其中长7油层组页岩油资源量超过10×108t,长7油层组致密砂岩油资源量约9×108t,长6油层组致密砂岩油资源量约11×108t。致密油资源是长庆油田实现年产油气当量5 000×104t并长期稳产较为现实的石油接替资源。
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Feasibility analysis of existing recoverable oil and gas resource in the Palaeogene shale of Dongying depression [J].东营凹陷古近系泥页岩中存在可供开采的油气资源 [J].
利用地球化学、岩石矿物、测井及录井等资料系统研究东营凹陷古近系沙河街组泥页岩，认为东营凹陷古近系沙三下亚段—沙四上亚段泥页岩厚度大，有机质丰度高、类型好、成熟度分布范围广，与北美地区已发现页岩气系统地质地球化学参数具有一定的可比性，具备形成页岩气的物质基础：东营凹陷沙三下亚段和沙四上亚段泥页岩全岩矿物组成具有较高石英和碳酸盐含量，粘土矿物含量低于50%，具有一定的脆性特征，且普遍发育微裂隙，有利于页岩油气的开采；东营凹陷古近系湖相泥页岩气测资料的调查发现，钻至沙三下亚段、沙四上亚段2套泥页岩发育段的探井气测显示均表现为高异常，钻井过程中频繁发生井涌和井漏现象，预示着气体的存在；2套泥页岩罐顶气轻烃（C<sub>1</sub>—C<sub>4</sub>)丰度随埋深增加而增加，在3 400m以深重烃/轻烃值较低，一般低于0.15，结合对2套泥页岩气油比的研究认为，东营凹陷针对泥页岩的勘探应采取油气兼探的方针。3 400m以浅以勘探泥页岩油藏为主，页岩气的勘探应在3 400m以深。研究表明，东营凹陷古近系泥页岩中存在可供开采的油气资源，是一个值得关注并投入风险勘探的新领域。<br />
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Formation conditions of Paleogene shale oil and gas in Jiyang depression [J].济阳坳陷古近系页岩油气形成条件 [J].
中国东部胜利油区济阳坳陷古近系主要发育陆相泥页岩沉积，至今尚未对陆相页岩油气形成进行系统研究。通过大量试油、录井、测井及测试资料分析认为，济阳坳陷发育沙四段上亚段、沙三段下亚段和沙一段3套陆相泥页岩，其分布面积广，厚度大，有机质丰度高，有机质类型以Ⅰ-Ⅱ。型为主，有机质成熟度已进入低成熟一高成熟演化阶段，无机矿物中脆性矿物含量高，表现出碳酸盐岩含量高、普遍含有一定量石英的特征，且各类微孔隙、微裂缝发育，形成的网状储集体系为油气的赋存与流动提供了空间，具备形成页岩油气的物质基础和储集条件。济阳坳陷沙四段上亚段页岩油气主要分布于东营凹陷、沾化凹陷和车镇凹陷郭局子洼陷；沙三段下亚段页岩油气主要分布于各凹陷的洼陷中部地区；沙一段页岩油气分布于沾化和车镇凹陷中部地区。
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Mechanism of shale oil enrichment in Jiyang depression [J].济阳坳陷页岩油富集机理 [J].
近年来，由于对页岩油富集机理认识不清，济阳坳陷页岩油勘探未获得突破。 在大量岩<br>心、分析化验资料、模拟实验和数理统计的基础上，明确了济阳坳陷页岩油富集机理：有机质是<br>页岩油生成的基础，页岩储集空间是页岩油富集的空间基础，异常压力是页岩油富集动力，有<br>机质演化程度控制了烃类流体类型，油气的可动性利于页岩油富集，岩相决定了页岩油类型。<br>在此基础上建立了页岩油富集模式，对济阳坳陷页岩油勘探有一定的指导意义。<br>
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An analysis on occurrences state and mobility of shale oil in Jiyang depression [J].济阳坳陷页岩油赋存状态和可动性分析 [J].
济阳坳陷页岩油气资源丰富，具有广阔的勘探前景。济阳坳陷页岩油赋存空间有孔隙、裂缝和夹层。济阳坳陷页岩油赋存状态有游离、溶解和吸附状态三种状态，以游离态和吸附态为主，含有少量溶解态页岩油。在页岩油生产井中仅发现游离态和溶解态页岩油。济阳坳陷页岩油在地层中的赋存状态这种多样性和差异性造成了页岩油在投产过程中含水率存在差异性。通过地层压力、地层水特征、碳同位素和生物标志化合物对比分析等资料，可以推断出济阳坳陷页岩油虽然源储同层，但大都发生了相当距离的初次运移，在“异地”聚集形成页岩油。该成果对分析页岩油形成机理有一定借鉴作用。
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Main control factors of enrichment characteristics of shale oil in Jiyang depression [J].济阳坳陷页岩油富集主控因素 [J]. |
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Shale organic heterogeneity evaluation method and its application to shale oil resource evaluation—A case study from Qingshankou Formation,southern Songliao Basin [J].泥页岩有机非均质性评价及其在页岩油资源评价中的应用——以松辽盆地南部青山口组为例 [J].
泥页岩存在较强的有机非均质性，实测地化数据受到样品数量的限制，难以精确描述油气在泥页岩体系中的分布特征。基于改进的Δlg<i>R</i>模型评价泥页岩有机质丰度和残留烃含量，参照页岩油资源评价分级标准，可清楚地刻画页岩油富集、低效、无效资源的空间分布。根据热解色谱分析参数校正实验和组分生烃热模拟实验，确定S<sub>1</sub>的重烃、轻烃补偿系数，采用体积法定量评价不同级别页岩油资源量，指明有利的勘探区块。研究结果表明，改进的Δlg<i>R</i>模型较好地改善了测井资料评价地化参数的精度，可操作性强。应用结果显示，松辽盆地南部青山口组页岩油资源主要富集在青山口组一段中、下部，区域上分布于扶新隆起、红岗阶地和长岭凹陷北部，富集资源量48.08×10<sup>8</sup> t，约占总资源量的1/3。通过有机非均质性刻画来评价页岩油气资源的分布特征，不仅阐明了页岩油的空间分布特征，而且还节约分析化验的成本，为页岩油下一步勘探开发提供实质性的指导。
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Accumulation conditions for continental shale oil and gas in the Biyang depression [J].泌阳凹陷陆相页岩油气成藏条件 [J].
摘要：泌阳凹陷AS1井陆相页岩储层压裂后获得最高日产油4.68 m3、天然气90 m3，从而在我国东部陆相第三系断陷湖盆页岩油气领域取得了重要突破。页岩油与页岩气通常为共生关系，文章将重点应用地质实验、地质录井、测井等资料对泌阳凹陷深凹区AS1井井区的页岩分布特征、地化特征、储集特征及保存条件进行分析。研究表明AS1井2 450~2 510 m主力页岩段单层厚度大，分布范围广，有机碳含量较高，热演化程度镜质体反射率值一般在0.57%～0.72%，表明烃源岩处于成熟阶段和生烃高峰期。含油气页岩录井气测异常明显，测井曲线上具有“三高两低”的特征；页岩储集空间类型发育微孔隙、微裂缝，储集性能较好；储层石英等脆性矿物含量高，易于页岩油储层压裂改造。采用容积法对泌阳凹陷深凹区页岩油气资源量进行计算，得出泌阳凹陷页岩油气资源量5.4×10.8 t，勘探潜力较大，勘探前景良好。
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Nano-hydrocarbon and the accumulation in coexisting source and reservoir [J].纳米油气与源储共生型油气聚集 [J]. |
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Conception,classification and resource potential of unconventional hydrocarbon [J].非常规油气有关概念、分类及资源潜力 [J].
尽管非常规油气的勘探开发已引起广泛重视，但对其概念的理解目前还存在一定差异，对其分类也未见有系统讨论。根据对非常规油气地质及开采特征的分析，将非常规油气定义为在油气藏特征与成藏机理方面有别于常规油气藏、采用传统开采技术通常不能获得经济产量的油气矿藏。非常规油气的内涵比连续油气聚集的含义广，后者是非常规油气资源中重要的组成部分，但不是全部。系统的分类研究表明，非常规油气可按其赋存相态分为气、液、固3类；按储层类型分为致密油气、页岩油气和煤层气；按油气分布特点或圈闭特征分为连续型、准连续型和不连续型；按源—储关系分为源内型和源外型；按成因分为原生型和次生型。初步分析认为，我国非常规石油原地资源量估计在720×10<sup>8</sup>t左右，可采资源量约为210×10<sup>8</sup>t（不包括致密油和页岩油），与常规石油资源量大体相当；非常规天然气原地资源量可能在320×10<sup>12</sup>m<sup>3</sup>左右，其中仅致密气、煤层气和页岩气3种主要非常规天然气的原地资源量可能高达175×10<sup>12</sup>m<sup>3</sup>左右，可采资源量估计在70×10<sup>12</sup>m<sup>3</sup>左右，相当于常规天然气可采资源量的3~4倍。另外，根据油气资源形成条件与成藏特征，提出了新的资源三角图的概念，将油气资源分为不连续的常规油气、准连续的致密油气和连续型聚集的源内油气3级，据此预测在致密储层发育的含油气盆地，致密油气的资源量虽可能小于页岩油气和煤层气等烃源岩层内聚集的油气资源数量，但可能大于常规油气的资源量。由于致密油气资源潜力大，储层条件相对好于其他非常规油气，因此建议我国非常规油气的勘探开发首先应以致密油气为主攻目标，其次应加强煤层气的勘探开发，同时积极开展页岩气资源潜力评价与先导试验研究。
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Unconventional petroleum resources assessment:Progress and future prospects [J].非常规油气资源评价进展与未来展望 [J].
近年来,国内外致密油、致密气、页岩气及煤层气等非常规油气资源评价取得重要进展，评价结果显示非常规油气资源非常丰富，勘探开发前景非常大。目前非常规油气资源评价方法也取得一些重要进展，分析了国内外具有代表性的方法进展，详细比较了5种主要类型方法(EUR类比法、资源丰度类比法、体积法、随机模拟法和成因法)的适用范围和优缺点。根据不同类型评价方法的优缺点及我国非常规油气资源评价现状分析，指出了我国未来非常规资源评价发展趋势:①采用统一评价流程和统一评价方法开展全国性资源评价，包括地质资源量评价和技术可采资源量评价；②采用改进后的资源丰度分级类比法、小面元体积法和EUR分级类比法等方法作为主要评价方法；③加强不同资源类型刻度区研究，建立起非常规油气资源评价的类比参数体系；④评价应包括经济评价和环境评估。
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Geological concepts, characteristics, resource potential and key techniques of unconventional hydrocarbon: On unconventional petroleum geology [J].非常规油气概念、特征、潜力及技术 [J]. |
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The efficiency and model of petroleum expulsion from from the lacustrine source rocks within geological frame [J].地质条件下湖相烃源岩生排烃效率与模式 [J]. |
| [19] |
Impact of hydrocarbon expulsion efficiency of continental shale upon shale oil accumulations in eastern China [J].
61Established dual evaluation criteria of absolute and relative oil content in shale.61Determined the relationship between shale oil content and organic matter type.61Discussed the factors affecting oil content of shale.61Researched the oil-bearing property of pores within different diameter scopes.
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| [20] |
Pore-throat sizes in sandstones, tight sandstones, and shales [J].
Pore-throat sizes in silidclastic rocks form a continuum from the submillimeter to the nanometer scale. That continuum is documented in this article using previously published data on the pore and pore-throat sizes of conventional reservoir rocks, tight-gas sandstones, and shales. For measures of central tendency (mean, mode, median), pore-throat sizes (diameters) are generally greater than 2 μm in conventional reservoir rocks, range from about 2 to 0.03 μm in tight-gas sandstones, and range from 0.1 to 0.005 μm in shales. Hydrocarbon molecules, asphaltenes, ring structures, paraffins, and methane, form another continuum, ranging from 100 03 (0.01 μm for asphaltenes to 3.8 A (0.00038 μm) for methane. The pore-throat size continuum provides a useful perspective for considering (1) the emplacement of petroleum in consolidated siliciclastics and (2) fluid flow through fine-grained source rocks now being exploited as reservoirs.
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| [21] |
Fractured shale-gas systems [J]. |
| [22] |
Shale gas potential of the Lower Jurassic Gordondale Member, northeastern British Columbia, Canada [J].
Le Membre de Gordondale du Jurassique inférieur est un mudstone organique riche, et est généralement considéré comme présentant un potentiel de réservoir de gaz de schiste. Les influences de la composition du mudstone du Membre de Gordondale sur ses capacités en gaz total (gaz sorbé et gaz libre) ont été déterminées afin d'évaluer le potentiel de ressource en gaz de schiste des couches dans le district de Peace River, au nord-est de la Colombie Britannique. Les capacités en gaz sorbé d'échantillons, en teneur d'humidité équilibrée, augmentent sur une gamme allant de 0.5 à 12 pour cent du poids du contenu en carbone organique total (TCO). Les capacités d'adsorption du méthane vont de 0.05 cc/g à plus de 2 cc/g dans les zones organiques riches (à 6 MPa et 30°C). Les capacités de sorption des mudstones, dans des conditions sèches, sont meilleures que dans des conditions d'humidité équilibrée, en raison de la présence d'eau dans les sites de sorption potentiels. Toutefois, il n'y a pas de diminution consistante de la capacité de sorption avec une augmentation de l'humidité, car cette relation se trouve masquée à la fois par la quantité de substance organique et le niveau de maturation thermale. La présence d'argiles affecte également les capacités de gaz total dans la mesure où les mudstones, riches en argile, présentent une haute teneur en porosité pouvant être disponible pour le gaz libre. Les échantillons de Gordondale, enrichis avec du carbonate (calcite et dolomie), présentent des porosités totales typiquement plus faibles que les roches pauvres en carbonate et, de ce fait, contiennent un potentiel plus faible en gaz libre. A l'échelle du réservoir régional, une grande proportion de la capacité totale de gaz du Gordondale est l'accumulation de gaz libre (porosité intergranulaire), s'étalant sur 0.1-22 Bcf/section (0.003-0.66 m
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| [23] |
China shale gas reservoir types and its controlling factors [J].中国页岩气的储层类型及其制约因素 [J].
页岩气是重要的非常规天然气能源。按页岩气储层的沉积环境将页岩分为海相、海陆过渡相和陆相页岩3种类型,由此总结了中国海相、海陆过渡相和陆相富有机质页岩的地层、分布及储层特征。海相页岩单层厚度大、分布范围大,空间连续性好;海陆过渡相地层中页岩具有单层薄、累积厚度大、频繁互层的特征;陆相页岩在平面上规模相对小、展布受到河湖相的控制。不同沉积相页岩在气体成分、赋存状态、气体成因等方面具有一定的共性,但由于页岩气储层的沉积环境不同,海相、海陆过渡相和陆相页岩在厚度、分布和岩性组合特征等方面又有较大差别。对比中美主要产气页岩储层的制约因素,结果表明,有机质丰度、有机质演化程度、有机质类型等因素制约着页岩的生烃;矿物的比例及结构、有机质的演化程度、有机质类型、孔隙及裂隙结构、页岩气赋存及运移条件、埋藏深度和有效厚度等因素影响页岩气富集成藏。
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| [24] |
Difference analysis on different types of shale oils in Jiyang depression [J].济阳坳陷不同类型页岩油差异性分析 [J].
济阳坳陷具备形成页岩油气的有利条件,但勘探效果不理想,亟需深入研究.为此,从划分页岩油类型入手,分析不同类型页岩油的差异性.根据页岩油的赋存空间和赋存岩石类型,可将研究区的页岩油划分为泥页岩型和夹层型页岩油2种类型;其中,泥页岩型页岩油可划分为基质型和裂缝型页岩油2个亚类,夹层型页岩油可划分为砂岩夹层型和碳酸盐岩夹层型页岩油2个亚类.提出根据裂缝发育系数划分页岩油类型的方法,将济阳坳陷裂缝发育系数大于0.2的泥页岩型页岩油确定为裂缝型页岩油,裂缝发育系数小于0.2的确定为基质型页岩油.研究区不同类型页岩油在空间分布、流体、物性、储集空间、赋存状态和产能等方面均存在差异.裂缝型页岩油和夹层型页岩油赋存于较大的储集空间,物性较好,赋存状态以游离态为主,因此裂缝型页岩油和夹层型页岩油的产能高于基质型页岩油.夹层型页岩油的储集空间小于裂缝型页岩油,气油比高,因此夹层型页岩油的产能低于裂缝型页岩油.
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| [25] |
Influence of Soxhlet-extractable bitumen and oil on porosity in thermally maturing organic-rich shales [J].
Comparative porosities of original and Soxhlet-extracted shale samples constrain the evolution of porosity along maturation, as well as the effect of partial oil/bitumen filling and blocking of pores. This study also employs FTIR analyses of DCM and toluene Soxhlet extracts to differentiate low-temperature DCM-extractable, mostly aliphatic OM from higher-temperature toluene-soluble OM containing condensed cross-linked polyaromatic structures.
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| [26] |
Effect of organic matter on pore structure of mature lacustrine organic-rich shale: A case study of the Triassic Yanchang shale, Ordos Basin, China [J].
The effect of extractable organic matter and solid organic matter on the pore structure of shale from Yangchang Formation in the Ordos Basin, China is investigated in this study. The shale samples were successively crushed, extracted by dichloromethane to remove extractable organic matter, treated by hydrogen peroxide to remove solid organic matter. The porosity, organic and mineralogical characteristic of original, extracted and H2O2treated shale samples were analyzed via low pressure gas adsorption measurement, X-ray diffraction (XRD) and Rock-Eval pyrolysis. Results show that pores in the studied shale were occupied and blocked by extractable organic matter with varying degrees which seriously affect porosity. Pores with small diameter will be preferential occupied and blocked. The plentiful generation of hydrocarbon in organic-rich shale will lead to high fluid pressure in pore which protect pore from compaction during evolution and lead to a higher porosity. This protection mainly act on macropores. Pores in the studied shale were dominated by quartz-related and clay-related pores, and organic matter hosted pore is rare. Solid organic matter content act as a harmful factor to total porosity of studied shale. Firstly, high content of solid organic matter reduce the relative content of quartz and clay minerals then lead to a low total porosity. Secondly, solid organic matter occupied and blocked pores related to quartz and clay minerals.
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| [27] |
Study on the distribution of extractable organic matter in pores of lacustrine shale: An example of Zhangjiatan Shale from the Upper Triassic Yanchang Formation, Ordos Basin, China [J].
Abstract Shale oil and gas have been discovered in the lacustrine Zhangjiatan Shale in the southern Ordos Basin, China. To study the distribution of extractable organic matter (EOM) in the Zhangjiatan Shale (Ro ranges from 1.25% to 1.28%), geochemical characterization of core samples of different lithologies, scanning electron microscope observations, low-pressure N2 and CO2 adsorption, and helium pycnometry were conducted. The content and saturation of the EOM in the pores were quantitatively characterized. The results show that the distribution of the EOM in the shale interval is heterogeneous. In general, the shale layers have a higher EOM content and saturation than siltstone layers. The total organic content and the original storage capacity control the EOM content in the shale layers. For the siltstone layers, the EOM content is mainly determined by the original storage capacity. On average, 75% of the EOM occurs in the mesopores, followed by 14% in the macropores, and 11% in the micropores. The EOM saturation in the pores decreases with the increase in pore diameter. The distribution of EOM in the shale pores is closely related to the pore type. Micropores and mesopores developed in the kerogens and pyrobitumens and the clay-mineral pores coated with organic matter are most favorable for EOM retention and charging. 漏 2017 Society of Exploration Geophysicists and American Association of Petroleum Geologists.
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| [28] |
Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity [J].
Tara gum has been considered as a possible replacement for carob gum in the formation of kappa carrageenan-galactomannan mixed gels. The mechanical properties of tara-carrageenan mixed gels have been measured and compared with the mechanical properties of carob-carrageenan mixed gels.
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| [29] |
Characterization of the porous structure of soils: Adsorption of nitrogen (77K) and carbon dioxide (273K), and mercury porosimetry [J].
Summary Accessibility of adsorbates to internal active sites of soils depends mainly on the porous structure of the material. We aimed to determine the distribution of pore sizes in soils with varied physico-chemical properties, by combining adsorption of gases and mercury porosimetry. Microporosity was studied by physical adsorption of N 2 at 77 K and CO 2 at 273 K; mercury intrusion porosimetry allowed us to evaluate the macroporosity; and mesoporosity was determined by capillary condensation of N 2 and mercury porosimetry. The soils investigated were essentially macroporous, with volumes between 0.33 and 0.73 cm 3 g –1 ; the maxima in the differential pore-size distribution were in the range 1500–4000 nm. Volumes of meso- or micropores were always less than 10% of macropore volumes. Calculations based on the theory of Dubinin and the α s -method (for N 2 at 77 K) provided, generally, coincident results. In a soil containing much organic matter, N 2 adsorption was only one-ninth that of CO 2 adsorption, showing that N 2 adsorption into the narrow micropores of organic matter was kinetically restricted. When accessibility to micropores was not restricted, the total volume of micropores could be deduced from N 2 adsorption, whereas CO 2 measured exclusively the narrowest microporosity.
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| [30] |
Factors influencing the specific surface areas of argillaceous source rocks [J].
This paper integrates methods of nitrogen adsorption (N 2 -BET) and ethylene glycol monoethyl ether (EGME) to present a comprehensive understanding of the specific surface areas (SSAs) of bulk rocks and clay fractions (<聽2聽渭m) in argillaceous source rocks, and employs the X-ray diffraction method to discuss the characteristics and influence factors of SSAs of argillaceous source rocks in order to service for unconventional petroleum exploration and exploitation. The methods of N 2 -BET and EGME can be used to obtain external surface area (N 2 -BET SSA) and total surface area (EGME SSA) within argillaceous source rock, respectively, and the difference between the total and the external surface area yields the internal surface area (internal SSA). The internal SSA accounts for over 80% in EGME SSA. Silty mudstone and argillaceous siltstone have larger internal and external surface areas than mud-bearing siltstone. Further, clay minerals (smectite in particular) make the greatest contribution to the internal, external and total surface areas (especially the internal and total surface areas) of source rock, whereas detrital minerals and carbonate minerals have a negative effect on each specific surface area. What is noteworthy is the fact that an abrupt increase in carbonate mineral content results in remarkable decreases in internal and EGME SSAs. These features therefore indicate that the differences in rock constituents (clay, detrital minerals and carbonate minerals) and mineral compositions affect the variations in SSAs characteristics of argillaceous source rocks. By plotting the SSAs vs. depth in bulk rocks and clay fractions, the variation extent of SSAs in clay fractions is better than that in bulk rocks. For either bulk rocks or clay factions, the value of internal SSA/N 2 -BET SSA changes abruptly from 20 in the shallow-part (above 1500聽m) to 5鈥10 in the deep-part (below 2000聽m). The evolution of minerals during diagenesis creates variability in the mineral content with burial depth, which causes a subsectional evolution of SSAs in the vertical. As the surfaces within argillaceous source rock are closely correlated with the occurrence of organic matter or hydrocarbon, analyses of the difference between internal surface area and external surface area give the result that the SSAs of argillaceous source rocks are influenced by the factors of rock types, mineral compositions, diagenesis, etc., so attention to specific mineral assemblage and burial depth are of great significance to enhance the success rate of petroleum exploration and development in argillaceous source rocks, particularly in the research of unconventional petroleum systems.
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| [31] |
Occurrence of stable and mobile organic matter in the clay-sized fraction of shale: Significance for petroleum geology and carbon cycle [J].
61TOC in clay-sized fraction can be categorized into stable and mobile OCs.61Different OCs varied in correlation with different mineral surface areas.61The forms of OM occurrence determine the stability and mobility of OC.61This study is of great significance for petroleum geology and carbon cycle.
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| [32] |
Effect of organic-matter type and thermal maturity on methane adsorption in shale-gas systems [J].
A series of methane (CH4) adsorption experiments on bulk organic rich shales and their isolated kerogens were conducted at 35°C, 50°C and 65°C and CH4 pressure of up to 15MPa under dry conditions. Samples from the Eocene Green River Formation, Devonian–Mississippian Woodford Shale and Upper Cretaceous Cameo coal were studied to examine how differences in organic matter type affect natural gas adsorption. Vitrinite reflectance values of these samples ranged from 0.56–0.58%Ro. In addition, thermal maturity effects were determined on three Mississippian Barnett Shale samples with measured vitrinite reflectance values of 0.58, 0.81 and 2.01%Ro. For all bulk and isolated kerogen samples, the total amount of methane adsorbed was directly proportional to the total organic carbon (TOC) content of the sample and the average maximum amount of gas sorption was 1.36mmol of methane per gram of TOC. These results indicate that sorption on organic matter plays a critical role in shale-gas storage. Under the experimental conditions, differences in thermal maturity showed no significant effect on the total amount of gas sorbed. Experimental sorption isotherms could be fitted with good accuracy by the Langmuir function by adjusting the Langmuir pressure (PL) and maximum sorption capacity (Γmax). The lowest maturity sample (%Ro=0.56) displayed a Langmuir pressure (PL) of 5.15MPa, significantly larger than the 2.33MPa observed for the highest maturity (%Ro>2.01) sample at 50°C. The value of the Langmuir pressure (PL) changes with kerogen type in the following sequence: type I>type II>type III. The thermodynamic parameters of CH4 adsorption on organic rich shales were determined based on the experimental CH4 isotherms. For the adsorption of CH4 on organic rich shales and their isolated kerogen, the heat of adsorption (q) and the standard entropy (Δs0) range from 7.3–28.0kJ/mol and from 6136.2 to 6192.2J/mol/K, respectively.
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| [33] |
Adsorption capacity of shale gas and controlling factors from the well Yuye 1 at the southeast of Chongqing [J].渝东南渝页1井页岩气吸附能力及其主控因素 [J].
页岩气是一种重要的非常规天然气,其中大部分的天然气以吸附态存在。为了探讨渝东南地区下志留统龙马溪组黑色页岩的天然气吸附能力和主控因素,对渝页1井的岩芯进行了系统地采样,并做了孔隙结构和体积、矿物组成、有机质含量、成熟度测定和等温吸附实验。实验测试结果显示,饱和吸附量VL在1.25～3.90 m3/t,平均为2.17 m3/t;Langmuir压力常数pL在1.90～9.48 MPa,平均为3.69 MPa。饱和吸附量与微孔体积具有负相关,与中孔体积和宏孔体积具有正相关。粘土矿物通过对微孔和中孔体积的控制来影响页岩的吸附能力,石英含量通过对宏孔体积的控制来影响页岩吸附能力。有机碳含量对页岩的吸附能力主要由其较发育的宏孔隙控制,另外,还可能有其他方面的影响因素,比如有机碳表面的亲油性对气态烃较强的吸附能力以及气态烃在无定形和无结构基质沥青体中的溶解作用等。当Ro〉2.0%时,饱和吸附量与Ro呈正相关,这可能与高成熟有机质中纳米级显微裂缝的发育导致宏孔体积的增加有关。
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| [34] |
Oil adsorption in shale nanopores and its effect on recoverable oil-in-place [J].
61We used molecular dynamics (MD) to study oil adsorption in shale nanopores.61There are always multiple adsorbed layers of liquid hydrocarbons in shale pores.61We developed a new model to estimate recoverable shale oil-in-place based on MD.61For Bakken, 13% of the oil-in-place is in adsorbed phase and difficult to produce.61We showed the potential of thermal processes to improve recoverable oil from shale.
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| [35] |
Classification and evaluation criteria of shale oil and gas resources: Discussion and application [J].页岩油气资源分级评价标准探讨 [J].
研究页岩油气资源分级评价标准,以准确评价页岩油气资源潜力。对松辽、海拉尔、济阳等5个地区烃源岩层地球化学指标进行统计分析,利用烃源岩含油量与TOC关系的"三分性",按富集程度将页岩油气分为分散(无效)资源、低效资源和富集资源3级;有机质大量生油/气的成熟阶段对应富集页岩油/气窗,页岩油气资源级别按TOC值划分。结合页岩中脆性矿物的含量、页岩(层系)的厚度、埋深等,定义评价页岩油气可采性的可采性指数并建立其计算公式,以定量评价页岩油气的可采性。实际应用中,根据用TOC-测井响应相关性确定的井剖面上的TOC值变化,可以得到不同级别页岩的等厚图及分级页岩油气资源量;再结合分级标准,利用TOC等值线和Ro等值线的叠合,可识别有利的页岩油气区。
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| [36] |
Characteristics and evaluation elements of shale oil reservoir [J].页岩油储层基本特征及评价要素 [J].
页岩油是指以游离、溶解或吸附状态赋存于有效烃源岩泥页岩中的液态烃类，是泥页岩生排烃后的残余滞留聚集，基本未经历运移或仅在源岩内短距离初次运移。目前，国内外对“页岩油”概念的界定不统一，对储层控制因素及评价要素的研究仍相对薄弱。明确了页岩油储层为泥页岩，不包括烃源岩内的其他岩类夹层及邻层，并依据储集机理差异将页岩油储层分为裂缝型和基质型。富含有机质、以Ⅰ型和Ⅱ1型干酪根为主、犚o值介于0.6％～1.2％、有机碳（TOC）值大于2.0％，矿物组成复杂、发育纹层结构，储集空间细小，低孔特低渗、储层需要改造是页岩油储层的基本特点。重点揭示了有机质在页岩油储层形成及评价中的重要作用，有机质含量影响页岩的生油潜力、储集能力并进而决定了页岩储层的含油量及产能，提出一套以有机碳含量为核心的储层分级评价标准，以TOC为2％、4％为界，同时综合考虑有机质类型及成熟度、富有机质页岩厚度、矿物组成及岩石类型、孔渗特征及岩石可压裂性等指标，将页岩油储层分为3级：Ⅰ类目标储层、Ⅱ类有利储层及Ⅲ类无效储层。
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| [37] |
CS2/NMP extraction of immature source rock concentrates [J].
Eleven Chinese immature source rock concentrates from the immature oil formations in four different depressions were extracted ultrasonically with a mixture of CS 2 and N -methyl-2-pyrrolidinone (CS 2 /NMP) at room temperature. The samples were also extracted with CHCl 3 and a mixture of methanol/acetone/chloroform (MAC) for comparison. The solvent system CS 2 /NMP is very efficient for the extraction of immature source rock concentrates, giving much higher extraction yields than CHCl 3 or MAC. The composition of the extracts using different solvent mixtures is also different. Model compound tests indicate that no chemical reactions have taken place between the NMP and the substrates in the extraction. These results suggest that there are abundant non-covalent bond interactions in the organic matter of the immature source rock concentrates. The fact that CS 2 /NMP mixed solvent extracts more than MAC and CHCl 3 is not only because it can dissolve higher molecular weight fractions, but also because it has stronger ability to disrupt the complex interactions existing between the soluble and insoluble fractions. Biomarker distributions in the saturated hydrocarbon fractions are different for different solvent systems, suggesting that care should be taken when comparing the biomarker parameters in source rocks when using different solvents for extraction.
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| [38] |
Two occurences of soluble organic matter determination in salty lacustrine source rocks and its significances [J].半咸—咸水湖相烃源岩中两种赋存状态可溶有机质的测定及其意义 [J]. |
| [39] |
Review: Organic matter removal from soils using hydrogen peroxide, sodium hypochlorite, and disodium peroxodisulfate [J]. |
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Occurrence and thermostability of absorbed organic matter on clay minerals in mudstones and muddy sediments [J].泥岩与沉积物中黏土矿物吸附有机质的三种赋存状态及其热稳定性 [J].
为研究有机质在粘土矿物中的赋存状态和二者的结合方式以及有机质的热稳定性,提取济阳坳陷东营凹陷古近系沙河街组泥质烃源岩和东海陆架表层泥质沉积物中的粘土组分(粒径<2 μm),依次进行索氏抽提、碱性水解和酸性水解处理,得到原始和相继处理过程所得碱解和酸解粘土样品及相应的有机组分,继而进行原始和碱解、酸解粘土样品的微观形貌(SEM)、比表面积(BET)、X-射线衍射(XRD)和热重/微分热重(TG/DTG)分析对比。结果显示,索氏抽提有机质主要赋存于粘土矿物外表面和堆积于孔隙中,碱解有机质主要赋存于粘土矿物边缘破键处,而酸解有机质主要赋存于膨胀型粘土蒙皂石层间。前者为物理吸附或束缚的游离有机质,后两者为化学吸附的结合有机质。有机质与粘土矿物的不同结合关系造成它们热稳定性的差异,显示出二者间复杂的作用关系及其对生烃的多阶段性影响。研究不同赋存态有机质的相对和绝对数量对深入研究油气成因和烃类初次运移具有十分重要的意义。
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| [41] |
Petroleum Formation and Occurrence [M]. |
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Penteado H D B. Rock-Eval 6 technology: Performances and developments [J]. |
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Hydrocarbon potential of the Barnett Shale (Mississippian), Delaware Basin, west Texas and southeastern New Mexico [J].
The Barnett Shale (Mississippian) in the Delaware Basin has the potential to be a prolific gas producer. The shale is organic rich and thermally mature over large parts of the basin. Depths to the Barnett range from 7000 ft (2133 m) along the western edge of the basin to more than 18,000 ft (5486 m) along the basin axis. The Barnett Shale began generating petroleum about 250 Ma and reached its maximum temperature about 260 Ma. Present-day thermal maturity is indicative of maximum burial and temperature. Wells in northern Reeves County are in the gas window based on measured vitrinite reflectance values and kerogen transformation ratios. The shale can be divided into an upper clastic unit and a lower limy unit by changes in resistivity. The lower unit can be subdivided into five subunits by distinctive well-log markers. Preliminary analyses suggest that intervals in the lower Barnett marked by high resistivity and high neutron porosity readings on well logs have high gas contents. Areas in which to focus the future exploration in the lower Barnett can be delineated by mapping a net resistivity greater than 50 ohm m. The Barnett Shale contains significant gas resources in the Delaware Basin. Realizing the potential of these resources depends on the current efforts to optimize drilling and completion techniques for this shale-gas play.
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| [44] |
Selection and verigication of key parameters in quantitative evaluation of shale oil: A case study at the Qingshankou formation, Northern Songliao basin [J].页岩油资源定量评价中关键参数的选取与校正 [J].
页岩油资源评价过程中,常用热解参数(S<sub>1</sub>)反映含油性。由于实验关系,所测得的S<sub>1</sub>存在轻烃、重烃的损失,为更准确的对页岩油资源进行定量评价,本文通过有机质成烃动力学研究以及对样品抽提前后的热解参数进行对比,对S<sub>1</sub>进行轻、重烃补偿校正,获得泥页岩总含油率参数,根据泥页岩排烃门限确定其可动油含量参数(<i>S</i><sub>1</sub>/TOC)。研究结果表明,松辽盆地北部青山口组泥页岩S<sub>1</sub>校正前后相差2~3倍,排烃门限对应的S<sub>1</sub>/TOC=75 mg/g TOC,结合黏土矿物含量(表征可压裂性),优选出页岩油勘探开发有利区:青一段有利区主要集中在齐家古龙凹陷中北部及龙虎泡大安阶地中部,青二、三段集中在龙虎泡大安阶地中部与齐家古龙凹陷中南部。
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| [45] |
An investigation on generation and expulsion of hydrocarbon from source rocks of the Shahejie formation in the well Niu-38, Dongying depression [J].东营凹陷牛38井沙河街组烃源岩生排烃评价 [J].
东营凹陷牛38井沙河街组三段烃源岩从沙三下亚段向沙三中-上亚段为一从高水位深湖相向低水位前三角洲相发展的沉积旋回,该沉积环境控制从下向上发育不同类型的有机质.相应地,该段烃源岩品质从下向上变差,其中沙三中亚段上部及沙三中亚段中部烃源岩产烃能力小,沙三下亚段烃源岩整体品质好,局部存在优质烃源岩.其优劣性体现了在该段烃源岩中,Ⅰ型干酪根具有高的生产力,而Ⅲ型、Ⅱ2型干酪根生烃潜力很低,基本为无效有机质.计算结果显示不同数据点的烃源岩单位质量原始生烃潜量可相差3个数量级,体现了烃源岩存在强烈的非均质性.有机碳的非均质性分布为其提供了物质基础,而湖盆的旋回式沉积及湖平面的波动性变化是其内在原因.同时,本文也提供一种计算生排烃量的新方法,结果表明该方法较为有效可行.
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| [46] |
A method for calculating the quantity of hydrocarbon generation and expulsion [J].一种生、排烃量计算方法探讨与应用 [J].
烃源岩的生烃量等于其残烃量与排出烃量之和.利用氯仿沥青"A"/总有机碳参数随深度的变化关系,可求出烃源岩的残烃率.在烃源岩演化过程中,(S1+S2)/总有机碳(生烃潜力指数)减小的唯一原因是有烃类从烃源岩中排出.无论生烃机制如何,烃源岩的现今生烃潜力指数与油气排出以前的原始生烃潜力指数之间的差值始终代表当前每克有机碳的排烃量(排烃率),据此可计算生成未熟-低熟油的烃源岩的排烃量.将排烃率与对应的残烃率叠加,可求出烃源岩的油气发生率,结合烃源岩的厚度、面积、密度及有机碳丰度等资料,可计算生烃量.在东营凹陷八面河油田应用此方法发现,该区下第三系沙三段、沙四段的泥岩与油页岩的生、排烃演化模式不同,泥岩的生烃量巨大,但排烃效率很低.图3表1参19(周杰摘)
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| [47] |
Characteristics of hydrocarbon expulsion for the lower Tertiary resource rocks in the Jiyang depression, the Bohaiwan Basin [J].渤海湾盆地济阳坳陷烃源岩排烃特征研究 [J].
烃源岩在埋藏演化过程中发生排烃的重要表现之一是其生烃潜力不断减小,反之也可利用烃源岩在演化过程中生烃潜力的变化规律来模拟其排烃特征。利用综合热解参数———生烃潜力指数[(<i>S</i><sub>1</sub>+<i>S</i><sub>2</sub>)/<i>TOC</i>]在热演化过程中的变化规律来确定源岩的排烃门限,并在此基础上模拟计算烃源岩在各演化阶段的排烃率、排烃速率及排烃效率。由于不同类型烃源岩的生烃潜力指数差别很大,在实际应用时应对不同类型源岩,含不同有机质类型的源岩进行区分。将此方法应用于济阳坳陷下第三系,发现油页岩和暗色泥岩具有不同的排烃特征,油页岩的排烃门限比暗色泥岩浅,排烃率也较高。
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| [48] |
The sedimentation of organic matter [M] |
| [49] |
Parameters and method for shale oil assessment: Taking Qingshankou formation shale oil of northern Songliao Basin [J].页岩油资源评价指标与方法——以松辽盆地北部青山口组页岩油为例 [J].
基于我国页岩油勘探开发现状,结合页岩油气资源调查评价及有利区优选的相关工作要求,研究泥页岩中滞留烃丰度的影响因素,提出页岩油资源评价指标及方法。研究结果表明：在统计分析松辽盆地青山口组一段泥页岩相关参数基础上,氯仿沥青质量分数w A不但与ws1（即热解中自由烃质量比）具有正相关关系,而且成分更接近原油,其值同时受泥页岩有机质丰度和成熟度的影响,并可以由此建立定量计算模型,w A是页岩油资源评价的重要参数。根据生烃动力学原理和本区残留烃量随成熟演化的趋势可知：页岩油富集有利区的残烃量下限为0.35%,并通过蒙特卡洛法可获得计算松辽盆地北部青一段页岩油有效资源量为96.41×10^8 t。
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| [50] |
The relationships between organic matter and specific surface in the clay fraction with diameter <2 μm of shale resource rocks [J].泥质烃源岩中<2 μm黏粒级组分的有机质与比表面关系 [J]. |
| [51] |
Characterization of organic matter fractions in an unconventional tight gas siltstone reservoir [J].
61Introduce an extended slow heating (ESH) Rock–Eval method for characterization of organic matter fractions in rock61Investigate role of various organic matter fractions in the reservoir quality of Montney tight gas siltstone61Propose a theory describing accumulation of solid bitumen from migration of paleo oil into the reservoir
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| [52] |
Methodological aspects of hydrocarbon shale resources assessment using different variants of volumetric methods [J].
The article presents the methodological aspects of hydrocarbon resources calculation accumulated in shale formations using two variants of the volumetric method based on different data sets. The first method constitutes an extension of the classic volumetric method taking into account adsorbed gas presence on kerogen surface. This method can be applied to formations saturated with oil, condensate, as well as dry gas. The second proposed method can be used for resources calculations in oil-saturated reservoirs only. It involves the use of geochemical data (Rock Eval pyrolysis data), results of PVT measurements of reservoir fluids and Langmuir isotherm. The possibility of using different methodological approaches allows to carry out calculations in different conditions of data availability. Both methods, used for test calculations of hydrocarbon resources in oil type shales, give surprisingly consistent results.
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| [53] |
Application of the rock-eval III oil show analyzer to the study of gaseous hydrocarbons in an Oklahoma gas well [C]// |
| [54] |
Oil and gas contents and movable oil amounts of shales in 4th member of Shahejie formation, Lijin subsag, Dongying sag [J].东营利津洼陷沙四段页岩含油气量测定及可动油率分析与研究 [J].
建立了页岩内含气量、液态轻质油、重质油的系统测定方法及页岩可动油实验方法，并对东营凹陷利津洼陷古近系沙河街组沙四段页岩样品的含气量、含液态油量、液态油性质及可动油率进行研究。研究结果表明：利津洼陷沙四段页岩含气量较低，勘探以页岩油为主。而液态油中含有较高的轻质油含量，并且具有较高的可动油比例，有利于利津洼陷沙四段页岩油的勘探开发。
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| [55] |
Resource evaluation and favorable area prediction on rich section of shale oil in Biyang depression [J].
泌阳凹陷页岩油富集段资源评价及有利区预测 [J].
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| [56] |
Quantitative evaluation of residual liquid hydrocarbons in shale [J].页岩滞留液态烃的定量评价 [J].
利用低温样品前处理技术并与地质分析相结合,建立了应用氯仿沥青"A"和热解参数定量评价页岩中滞留烃的方法。通过自生自储油气藏中原油与烃源岩氯仿抽提物组分对比,建立了东营凹陷主要生油窗范围内氯仿沥青"A"轻烃恢复系数随烃源岩生烃演化而变化的关系曲线,Ro小于0.5%,氯仿沥青"A"恢复系数较小,其重要增加发生在Ro为0.7%以后,Ro在1.2%时达到1.40以上。通过新鲜冷冻样品与常温保存样品的对比,建立了热解过程中散失轻烃的确定方法,并建立了不同演化阶段的散失系数,其变化规律与氯仿沥青"A"恢复系数相似。通过原样及抽提残渣的热解对比分析,建立了不同演化阶段烃源岩热解S2中滞留烃的比例系数,在成熟阶段(Ro为0.8%),这一比例可高达50%以上。通过上述技术方法,可以客观评价页岩中滞留烃含量,对油气资源评价具有重要意义。
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| [57] |
The discussion of the evaluation method of shale oil movable resources amount and Palaeogene Shahejie formation application effect in the northern of Dongpu depression [J].页岩油可动资源量评价方法探讨及在东濮凹陷北部古近系沙河街组应用 [J].
中国页岩油资源潜力巨大，而页岩油的可动性评价影响了该类资源的勘探与开发。本文提出一种泥页岩油可动资源量评价方法，具体包括以下内容：①划分泥页岩层系，识别标准为：起始段和结尾段为大于2m的泥页岩段，单层泥页岩内有机质成熟度(R<sub>O</sub>)和有机碳均值大于0.5%，单层砂岩厚度小于2m，10m范围内薄砂层累计厚度小于4m，总厚度≥30m，页岩油可动资源量评价是针对狭义的泥页岩；②页岩饱和吸附油量评价模型，是基于泥页岩体积(展布、厚度)、有机碳、泥页岩密度和饱和吸附系数4个参数建立的；③原地页岩油资源量评价模型，是依据页岩含油率、泥页岩体积、岩石密度及轻烃重烃补偿系数4个参数建立的；④页岩油可动资源量评价模型，结合物质平衡原理，页岩油可动资源量等于原地页岩油资源量减去页岩油饱和吸附油量。应用上述方法对东濮凹陷古近系沙河街组沙一段、沙三上亚段、沙三中亚段、沙三下亚段泥页岩层系内页岩油资源量进行评价，结果为：沙一段、沙三上亚段、沙三中亚段及沙三下亚段泥页岩层系内页岩油可动资源量分别为1.27×10<sup>8</sup>t、4.27×10<sup>8</sup>t、2.73×10<sup>8</sup>t和2.59×10<sup>8</sup>t，柳屯洼陷具有很大的勘探潜力。
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| [58] |
Calculation of petroleum masses generated and expelled from source rocks [J].
An algebraic scheme for calculating the masses of petroleum formed in mature source rocks has been constructed. The scheme exploits routine geochemical measurements and a basic understanding of the behaviour of sedimentary organic matter at elevated temperatures under both laboratory and subsurface conditions. Application of these techniques to data from a wide range of source rock types has led to the following general conclusions: 1. 1. Major oil and gas generation from kerogen occurs between 120 and 150°C in the subsurface; gas generation continues to temperatures 88 160° C. 2. 2. Oil-prone source rocks with average initial potential > 5 kgt 611 of rock and average organic carbon contents > 1.5% expel 60–90% of the total oil generated. 3. 3. Oil expulsion from leaner source rocks is less efficient. Most of the oil generated remains in the source rock; it is subsequently converted to lighter components at higher temperatures and expelled in the vapour state. 4. 4. The major loss of organic carbon from rich oil-prone source rocks during generation and expulsion means that the petroleum potential and organic carbon content of mature source rocks are much less than their initial immature values. Hence the algebraic scheme must be used to calculate the initial values before expelled petroleum masses can be determined.
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| [59] |
S1 peak of Rock-Eval analysis: What does it represent for unconventional hydrocarbon resource assessment? [C]// |
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Hydrocarbon evaporative loss from shale core samples as revealed by Rock-Eval and thermal desorption-gas chromatography analysis: Its geochemical and geological implications [J].
The S1 peak generated by Rock-Eval analysis of source rock and reservoir interval core and cuttings samples has been routinely employed for in-place hydrocarbon resources assessment by petroleum geochemists, geologists and even engineers. Significant evaporative loss of gaseous and light hydrocarbons (up to C 10 ) can occur during core and cuttings collection and storage, and subsequent sample preparation in the laboratory before instrumental analysis. Consequently a correction to the S1 values is needed in order to obtain a more accurate estimate of the resources. To investigate the effect of evaporative loss on both the amount and the composition of the hydrocarbons retained in shale, a time-series of Rock-Eval and thermal desorption-gas chromatography (TD-GC) analyses have been carried out on an organic-rich Devonian Duvernay Formation shale core sample from the Western Canada Sedimentary Basin (WCSB) and an organic-lean Ordovician Lotbinière Formation shale core sample from Quebec, Canada. The results suggest that the content of total organic carbon (TOC) may play an important role in retaining and preserving light hydrocarbons in sedimentary rocks. A total loss of gaseous and light liquid hydrocarbons up to C 9 is shown to take place within 21h of sample preparation for the low TOC (11%) Devonian Duvernay shale core sample. After 360h of exposure to the open air, the powdered Duvernay shale sample shows only 15% decline in its Rock-Eval S1 peak, and still contains high relative concentrations of C 7 –C 9 hydrocarbons. In addition, the evaporative loss of some isomers of C 5 –C 7 hydrocarbons from the organic-rich shale is not fully in agreement with their GC retention/elution behavior, but appears to be partially controlled by their adsorption/desorption on the organic matter and mineral matrix. This suggests that the C 5 –C 8 gasoline range hydrocarbon parameters should be used with caution for oil–oil correlation for unconventional shale and tight petroleum systems. While the findings in this study validate the current industrial practice that targets organic-rich and mature shale intervals for unconventional shale gas and oil exploration because of their large hydrocarbon storage capacity, the results also have an important implication that high TOC content may adversely affect the production efficiency of shale and tight hydrocarbon reservoirs due to the strong adsorption of hydrocarbons by the high maturity organic matter.
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| [61] |
Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett Shale [J].
Research on mudrock attributes has increased dramatically since shale-gas systems have become commercial hydrocarbon production targets. One of the most significant research questions now being asked focuses on the nature of the pore system in these mudrocks. Our work on siliceous mudstones from the Mississippian Barnett Shale of the Fort Worth Basin, Texas, shows that the pores in these rocks are dominantly nanometer in scale (nanopores). We used scanning electron microscopy to characterize Barnett pores from a number of cores and have imaged pores as small as 5 nm. Key to our success in imaging these nanopores is the use of Ar-ion-beam milling; this methodology provides flat surfaces that lack topography related to differential hardness and are fundamental for high-magnification imaging.Nanopores are observed in three main modes of occurrence. Most pores are found in grains of organic matter as intraparticle pores; many of these grains contain hundreds of pores. Intraparticle organic nanopores most commonly have irregular, bubblelike, elliptical cross sections and range between 5 and 750 nm with the median nanopore size for all grains being approximately 100 nm. Internal porosities of up to 20.2% have been measured for whole grains of organic matter based on point-count data from scanning electron microscopy analysis. These nanopores in the organic matter are the predominant pore type in the Barnett mudstones and they are related to thermal maturation.Nanopores are also found in bedding-parallel, wispy, organic-rich laminae as intraparticle pores in organic grains and as interparticle pores between organic matter, but this mode is not common. Although less abundant, nanopores are also locally present in fine-grained matrix areas unassociated with organic matter and as nano- to microintercrystalline pores in pyrite framboids.Intraparticle organic nanopores and pyrite-framboid intercrystalline pores contribute to gas storage in Barnett mudstones. We postulate that permeability pathways within the Barnett mudstones are along bedding-parallel layers of organic matter or a mesh network of organic matter flakes because this material contains the most pores.
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| [62] |
Movability of lacustrine shale oil: A case study of Dongying sag, Jiyang depressiong, Bohai Bay Basin [J].湖相页岩油可动性——以渤海湾盆地济阳坳陷东营凹陷为例 [J]. |
| [63] |
Low-tempreture closed extraction technology of light hydrocarbons and its application in evaluation of shale oil resource [J].轻质烃组分的低温密闭抽提技术及其在页岩油资源评价中的应用 [J]. |
| [64] |
Characterization technique II of mineral material based on probe gas adsorption isotherm: Nano-pore struture of porous material [J].基于探针气体吸附等温线的矿物材料表征技术II.多孔材料的孔隙结构 [J].
含纳米孔的天然矿物岩石材料的吸附和催化性能对于表生地球化学过程、材料加工、应用及煤炭开发利用等方面均有着重要意义。本文对比分析了各种纳米孔表征技术,重点介绍了基于吸附等温线的纳米孔研究方法。对三个典型样品等温线数据的模型计算表明,应根据材料中孔的形态(平行板状孔、球形孔和圆柱形孔)选择模型,不同类型孔所对应的计算方法和参数有很大差别。表征材料表面能量均匀的样品可首先考虑采用DFT法;HK法一般只作为定性研究方法,BJH方法受样品本身性质参数的影响较小,且计算简单,可广泛应用于介孔材料的孔径分布的表征。
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| [65] |
Pore structure characterization of North American shale gas reservoirs using USANS/SANS, gas adsorption, and mercury intrusion [J].
Small-angle and ultra-small-angle neutron scattering (SANS and USANS), low-pressure adsorption (N-2 and CO2), and high-pressure mercury intrusion measurements were performed on a suite of North American shale reservoir samples providing the first ever comparison of all these techniques for characterizing the complex pore structure of shales. The techniques were used to gain insight into the nature of the pore structure including pore geometry, pore size distribution and accessible versus inaccessible porosity. Reservoir samples for analysis were taken from currently-active shale gas plays including the Barnett, Marcellus, Haynesville, Eagle Ford, Woodford, Muskwa, and Duvernay shales.Low-pressure adsorption revealed strong differences in BET surface area and pore volumes for the sample suite, consistent with variability in composition of the samples. The combination of CO2 and N-2 adsorption data allowed pore size distributions to be created for micro-meso-macroporosity up to a limit of similar to 1000 angstrom. Pore size distributions are either uni- or multi-modal. The adsorption-derived pore size distributions for some samples are inconsistent with mercury intrusion data, likely owing to a combination of grain compression during high-pressure intrusion, and the fact that mercury intrusion yields information about pore throat rather than pore body distributions.SANS/USANS scattering data indicate a fractal geometry (power-law scattering) for a wide range of pore sizes and provide evidence that nanometer-scale spatial ordering occurs in lower mesopore-micropore range for some samples, which may be associated with inter-layer spacing in clay minerals. SANS/USANS pore radius distributions were converted to pore volume distributions for direct comparison with adsorption data. For the overlap region between the two methods, the agreement is quite good. Accessible porosity in the pore size (radius) range 5 nm-10 mu m was determined for a Barnett shale sample using the contrast matching method with pressurized deuterated methane fluid. The results demonstrate that accessible porosity is pore-size dependent. (C) 2012 Elsevier Ltd. All rights reserved.
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| [66] |
Specific surface area and pore-size distribution in clays and shales [J].
ABSTRACT One of the biggest challenges in estimating the elastic, transport and storage properties of shales has been a lack of understanding of their complete pore structure. The shale matrix is predominantly composed of micropores (pores less than 2 nm diameter) and mesopores (pores with 2–50 nm diameter). These small pores in the shale matrix are mainly associated with clay minerals and organic matter and comprehending the controls of these clays and organic matter on the pore-size distribution is critical to understand the shale pore network. Historically, mercury intrusion techniques are used for pore-size analysis of conventional reservoirs. However, for unconventional shale reservoirs, very high pressures (> 414 MPa (60 000 psi)) would be required for mercury to access the full pore structure, which has potential pitfalls. Current instrumental limitations do not allow reliable measurement of significant portions of the total pore volume in shales. Nitrogen gas-adsorption techniques can be used to characterize materials dominated by micro- and mesopores (2–50 nm). A limitation of this technique is that it fails to measure large pores (diameter >200 nm). We use a nitrogen gas-adsorption technique to study the micro- and mesopores in shales and clays and compare the results from conventional mercury porosimetry techniques. Our results on pure clay minerals and natural shales show that (i) they have a multiscale pore structure at different dimensions (ii) fine mesopores, with a characteristic 3 nm pore size obtained with N 2 gas-adsorption are associated with an illite-smectite group of clays but not with kaolinite; (iii) compaction results in a decrease of pore volume and a reduction of pore size in the ‘inter-aggregate’ macropores of the illite-smectite clays while the fine ‘intra-tachoid’ mesopores are shielded from compaction; (iv) for natural shales, mineralogy controls the pore-size distributions for shales and the presence of micropores and fine mesopores in natural shales can be correlated with the dominance of the illite-smectite type of clays in the rock. Our assessment of incompressible 3 nm sized pores associated with illite-smectite clays provides an important building block for their mineral modulus.
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| [67] |
Total porosity measurement in gas shales by the Water Immersion Porosimetry (WIP) method [J].
Over the past decade interest in shale properties has increased due to the commercial success of gas shale plays. Despite their commercial importance, porosity measurement from gas shale samples is still challenging due to their extremely low permeability and complex pore structure. This leads to a significant uncertainty in the economic assessment of these plays. The current energy industry standard technique for measuring porosity in gas shales is based on methodology developed by the Gas Research Institute (GRI) that involves crushing a rock and aggressive pretreatment. The objective of this study is to develop an alternative method of measuring total porosity in gas shales. A porosity measurement using a liquid saturation and immersion technique with deionized water was adopted and modified for such applications. The water immersion porosimetry (WIP) technique was used to measure total porosity of shale samples from an Eastern Europe Silurian gas shale play and the Haynesville Shale from East Texas, USA. The samples were characterized for whole rock quantitative mineral and elemental composition, along with cation exchange capacity (CEC) and organic matter. The results from the WIP measurements are compared with other standard techniques including the GRI method and mercury intrusion porosimetry (MIP). An assessment of the advantages, potential errors, pitfalls and reproducibility of this method are also presented. The experimental results indicate that WIP provides (i) highly reproducible porosity, grain density, and bulk density measurements for gas shales, (ii) the average absolute experimental uncertainty is 卤0.22 porosity unit (p.u.), compared to the reported uncertainty level of 0.5p.u. for GRI measurements, (iii) standard MIP techniques systematically underestimate the porosity and grain density compared to WIP, because mercury cannot access the entire pore structure in shales, and (iv) grain density values obtained by the GRI method in samples with high organic matter content are higher compared to WIP measurements, probably because of dissolution of solid organic matter during solvent extraction pretreatment.
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| [68] |
Characteristics of lacustrine shale porosity evolution, Triassic Chang 7 Member, Ordos Basin, NW China [J].
With low mature Triassic Chang 7 Member shale samples from the Ordos Basin as study object, the 3-D porosity evolution with temperature increase and its main controlling factors are analyzed based on the physical modeling under high temperature pressure and nano-CT scanning data. More and more nano-pores were developed in Chang 7 Member organic-rich shale with the increase of maturity. The porosity calculated from the nano-CT scanning model increased from 0.56% to 2.06%, more than 250% times larger, when temperature increased from 20 鈩 to 550 鈩. The process of porosity evolution can be divided into three phases. Firstly, porosity decreased rapidly from immature to low mature stage because of weak hydrocarbon generation and strong compaction; Secondly, porosity increased rapidly when the maturity increased from low mature stage to mature and post-mature stage, organic matter cracked into hydrocarbon(HC) massively, and clay minerals transformed intensively; Thirdly, porosity system kept stable when the shale entered into post-mature stage and the intensity of both HC generation and clay mineral transformation decreased. Organic matter thermal evolution, clay mineral transformation and brittle mineral transformation make different contribution to the porosity of shale, and the ratio is 6:3:1 respectively. It is inferred abundant organic matter pores occur when Ro is over 1.2%.
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| [69] |
Unconventional shale-gas systems: The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment [J]. |
| [70] |
Development of organic porosity in the Woodford Shale with increasing thermal maturity [J].
Using a combination of focused ion beam milling and scanning electron microscopy we describe the evolution of secondary organic porosity in eight Woodford Shale (Late Devonian鈥揈arly Mississippian) samples with mean random vitrinite reflectance values ranging from 0.51% Ro to 6.36% Ro. Organic porosity was observed to be absent in samples with vitrinite reflectance values of up to 0.90% Ro with the first appearance of secondary pores starting with the 1.23% Ro sample. Porosity in the organic matter was unexpectedly absent in a sample with a vitrinite reflectance of 2.00% Ro; however, organic pores were again found in samples with higher thermal maturities. Porosity, when present, did not appear to be uniformly distributed among the organic matter that was within less than a micron of each other suggesting important differences in composition of the organic matter. Thin regions of organic matter were observed between grains raising the possibility that small amounts of the deposited organic matter were compacted between grains to form thin layers and/or the structures are part of the secondary organic matter (interpreted to be post-oil bitumen) which was left behind as a residue during oil migration through the shale. Some regions of porous organic matter appeared to be grain protected whereas others did not which indicates that these non-protected porous organic regions may be stress supporting with porosity intact under in situ reservoir conditions. These observations suggest that thermal maturity alone is insufficient to predict porosity development in organic shales, and other factors, such as organic matter composition, complicate porosity development.
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| [71] |
Characterization of gas shale pore systems by porosimetry, pycnometry, surface area, and field emission scanning electron microscopy/transmission electron microscopy image analyses: Examples from the Barnett, Woodford, Haynesville, Marcellus, and Doig units [J]. |
| [72] |
Evolution of nanoporosity in organic-rich shales during thermal maturation [J].
Artificial shale samples with equivalent vitrinite reflectance values (VRo) ranging from 0.69% to 4.19% were obtained from an anhydrous pyrolysis experiment. Microporous and mesoporous characteristics of these samples were investigated by low-pressure nitrogen and carbon dioxide adsorption techniques. The result shows that the nanoporosity (microporosity plus mesoporosity) increases with thermal maturity after the oil window stage, and this increase is attributed to the formation of porosity within organic matter and/or mineral鈥搊rganic matter groundmass, rather than in the pure clay minerals. By combining the gas generation and porosity evolution of these shales, a general model for formation and development of the nanoporosity is proposed.
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| [73] |
Evolution and models of shale porosity during burial progress [J].泥页岩埋藏过程孔隙度演化与预测模型探讨 [J].
<div style="line-height: 150%">统计分析了国内外大量实测及测井解释孔隙度数据，揭示泥页岩孔隙度演化规律，指出孔隙度变化过程的差异，划分出正常压实和欠压实孔隙演化区。从3个方面探讨了引起孔隙度差异的原因：①处于生油高峰期的优质烃源岩，生烃过程中产生的超压减缓了孔隙度变小的速率，是泥页岩在中深层还保持相对较大孔隙度的主要因素，超压贡献的孔隙度超过5%；②处于生气中晚期的优质烃源岩，生烃过程形成的有机质纳米孔隙是深层富含有机质泥页岩孔隙度增加的另一个重要因素，有机质纳米孔贡献泥页岩孔隙度达到1.8%；③有机酸对脆性矿物的溶蚀作用对泥页岩孔隙增大贡献比预想的小。根据以上认识，建立了3段式的正常压实模型、欠压实模型以及有机质纳米孔校正模型，分析了模型关键参数，提出了有机质面孔率的估算模板。应用实例证明这些模型具有实用价值，可促进页岩气、页岩油等非常规油气资源评价及勘探开发技术的发展。</div><div style="line-height: 150%"> </div>
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| [74] |
New pore-scale considerations for shale gas in place calculations [C]// |
| [75] |
Molecular dynamics simulations of oil transport through inorganic nanopores in shale [J].
Understanding the transport of liquid hydrocarbon through nanopores of inorganic minerals is crucial not only to develop liquid-rich shale reservoirs, but also to grasp oil migration from deeply buried extremely low permeability source rocks. We report a molecular study of liquid hydrocarbon (octane) flow through inorganic (quartz) nanopores ranging in size from 1.7 to 11.2nm. Through equilibrium molecular dynamics (EMD), we observe the layering structure of confined octane and conclude that in the center of slits having apertures greater than 3.6nm, the octane properties, e.g., density, self-diffusion coefficient, and viscosity, tend to be bulk-liquid-like. Near the solid–liquid interface, octane molecules diffuse more slowly. Then we use nonequilibrium molecular dynamics (NEMD) to study the pressure-driven flow of octane in quartz slits and present two methods to characterize the behavior: (1) slip length coupled with effective viscosity and (2) apparent viscosity. The Navier–Stokes equation can reasonably describe the flow in quartz nanopores larger than 1.7nm; however, a slip boundary condition or viscosity correction is essential. Although the slip length (650.9nm) is small, significant error can be caused in the estimation of overall flux if it is neglected. The variations in slip length and apparent viscosity with driving force, pore size, and temperature can be described by empirical exponential functions. These results can be readily incorporated into existing techniques to estimate apparent liquid permeability of shale—the most fundamental property required for shale exploitation.
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| [76] |
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| [77] |
Sorption of organic contaminants in mineral micropores: Mechanism and major controlling factors [J].矿物微孔对有机污染物吸附的机理和影响因素 [J].
有机污染物对地表和地下水环境的污染是当前环境保护领域的重要问题之一。矿物的微孔结构(<2.0nm)对有机污染物在地下水环境中的长期迁移与归宿以及吸附处理污染水体方面具有重要的意义和应用价值。本文在介绍矿物微孔吸附机理的基础上,探讨了矿物孔道的表面化学性质,有机污染物本身的物理化学性质,以及水环境中的共存溶解性有机质和金属离子对有机污染物在矿物微孔中吸附的影响。
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| [78] |
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| [79] |
Effect of smetite illitization on shale gas occurrence in argillaceous source rocks [J].泥质烃源岩中蒙脱石伊利石化对页岩气赋存的影响 [J].
页岩气的赋存受多种因素的制约，作为泥质烃源岩中最主要的2种黏土矿物，蒙脱石和伊利石在比表面和微孔隙上存在的明显差异决定了蒙脱石更有利于页岩气的赋存。成岩过程中的压实作用和蒙脱石向伊利石的转化以及由此产生的异常压力都会改变蒙脱石和伊利石的性质，进而影响到对页岩气的吸附。然而，泥质烃源岩中蒙脱石层间有机质的存在，一定程度上延缓了蒙伊化进程，也会对页岩气的吸附产生重要影响。将泥质烃源岩中蒙脱石伊利石化与蒙脱石层间有机质演化以及层间水脱水过程联系起来分析发现，成岩过程中层间有机质排出以前以及层间水排出时期，即从无序伊蒙混层向部分有序混层转化的阶段（伊蒙混层比50%~35%）以及有序伊蒙混层形成的末期（伊蒙混层比15%左右），对应页岩气的有利富集期。
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| [80] |
High-pressure adsorption of methane on montmorillonite, kaolinite and illite [J].
Methane (CH 4 ) adsorption of Ca 202+ -montmorillonite (Mt), kaolinite (Kaol) and illite (Il) at 6002°C and pressures up to 18.002MPa was investigated, during which the adsorption capacity was evaluated by the Langmuir adsorption model. The influences of adsorbed water and the interlayer distance of the clay minerals on CH 4 adsorption were explored by using heated Mt products with different interlayer distances as the adsorbent. Mt, Kaol and Il showed high CH 4 adsorption capacities, and their maximum Langmuir adsorption capacities were Mt, 6.0102cm 3 /g; Kaol, 3.8802cm 3 /g; and Il, 2.2202cm 3 /g, respectively. CH 4 was adsorbed only on the external surface of Kaol and Il; however, adsorption also occurred in the interlayer space of Mt, which had a larger interlayer distance than the size of a CH 4 molecule (0.3802nm). CH 4 adsorption in the interlayer space of Mt was supported by the lower CH 4 adsorption capacity of heated Mt products (with the interlayer distance <020.3802nm) than that of Mt at high pressures despite the higher external surface areas of the heated Mt samples. The entrance of CH 4 into the interlayer space of Mt occurred at low pressures, and more CH 4 molecules entered the interlayer space at high pressures. Moreover, the adsorbed water occupied the adsorption sites of the clay minerals and decreased the CH 4 adsorption capacity. These results indicate that clay minerals play a significant role in CH 4 adsorption of shale and indicate that the structure and surface properties of clay minerals are the important parameters for estimating the gas storage capacity of shale.
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| [81] |
Experimental investigation of main controls to methane adsorption in clay-rich rocks [J].
A good linear relationship between the natural logarithm of Langmuir constant and the reciprocal of temperature exists for clay-mineral dominated rocks, which provides a way to quantify the impact of clay mineral type on gas adsorption capacity. Thermodynamic parameters, the heat of CH 4 adsorption and the standard entropy, are calculated based on this linear correlations. The heat of adsorption ( q ) and the standard entropy (Δ s o ) range from 9.4 to 16.602kJ/mol and from 6164.8 to 6179.502J/mol/K, respectively, values considerably smaller than those for CH 4 adsorption on kerogens. Thus, it is expected that CH 4 molecules may preferentially occupy surface sites on organic matter, in addition, the clay minerals are easily blocked by water. As a consequence, organic-rich mudrocks possess a larger CH 4 sorption capacity than clay-dominated rocks lacking organic matter.
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| [82] |
Comparison and explanation of the absorptivity of organic matters and clay minerals in shales [J].页岩中有机质与黏土矿物对甲烷吸附能力的探讨 [J].
以南方中下扬子地区高—过成熟页岩样品为研究目标，通过低温液氮吸附、压汞实验等孔隙分析手段，以及等温吸附实验等，利用SPSS软件分析TOC含量、成熟度、黏土矿物含量对样品吸附能力的影响，得出TOC含量、成熟度Ro、黏土矿物含量对样品最大吸附量的影响系数分别为0.326，-0.061，0.028。其中TOC含量、黏土矿物含量的增加对提升样品吸附能力具有正面作用。利用X射线衍射、扫描电镜对样品成分、形貌进行分析，结果指示有机质面孔率明显高于矿物基质，与伊利石相比，伊蒙混层具有良好的多孔性与联通性。
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| [83] |
Mineral surface control of organic carbon in black shale [J].
Abstract We show that 85% of variation in total organic carbon can be explained by mineral surface area in a black shale deposit from two locations in the late Cretaceous Western Interior Seaway, United States. This relation suggests that, as in modern marine sediments, adsorption of carbon compounds onto clay mineral surfaces played a fundamental role in the burial and preservation of organic carbon. Our data also provide evidence for organic matter within the smectite interlayer. This association implies that organic carbon sequestration in a representative oil-prone black shale facies may be more closely related to patterns of continental weathering and clay mineralogy than to ocean water chemistry or marine productivity.
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| [84] |
Interpreting Rock-Eval pyrolysis data using graphs of pyrolizable hydrocarbons vs. Total Organic Carbon [J].
Kerogen, the major organic component of sedimentary rocks, is commonly analyzed by Rock-Eval pyrolysis. Plotting the data on a graph of S{sub 2} vs. total organic carbon (TOC) and determining the regression equation is the best method for determining the true average hydrogen index and measuring the adsorption of hydrocarbon by the rock matrix. Such a plot also indicates the type of kerogen present and avoids the problem of increasing hydrogen index with total organic carbon content. With the S{sub 2} vs. TOC diagram, the organic component of different suites of samples may be compared and their petroleum-generation potentials established. As an example, the diagrams are used to evaluate the sedimentary environments and petroleum potential of the Paleogene evaporitic sediments of the Mulhouse basin, Alsace, France. 4 figs., 2 tabs.
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| [85] |
A new approach to interpreting Rock-Eval S2 and TOC data for kerogen quality assessment [J].
A simple method for application in source potential mapping is used to assess the original oil and gas potentials in source rock horizons based upon Rock-Eval potential ( S 2) and total organic carbon (TOC) values. The method assumes that kerogens consist of mixtures of end-members with assigned hydrogen index values. Based on suggested algorithms, the average amounts of oil-prone, gas-prone and inert organic material over source rock intervals are determined in TOC units. The method uses regression lines from plots of remaining hydrocarbon potentials ( S 2) versus total organic carbon (TOC), and “quick-look” transparent overlays are used to read the appropriate kerogen mixture. Mineral matrix effects during pyrolysis, when strong, can cause erroneous results. This effect which occurs for oil-prone kerogens and adsorptive minerals can cause problems particularly for lean samples ( S 2 = 0–3 mg HC/g rock) whilst the errors for richer samples are less. The method is applied on three sections of Upper Jurassic organic-rich rocks from the Danish North Sea sector, which are at different maturity stages. One of these sections is dominated by gas-prone material, one is dominated by oil-prone material and the third section contains a mixture of oil- and gas-prone material. The method has been compared with other methods that split kerogens in oil and gas generating potential and has given reasonable results. Experience using the method and a presented example suggest that sedimentological, system tract information may be derived from S 2 to TOC cross-plots. A constructed modelling example suggests that the end-member concept used in this approach may be used in forward type source rock prediction models when combined with sedimentological models. The resulting S 2–TOC plots can be used in order to check the forward modelling results against observed values.
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| [86] |
Interpreting Rock-Eval pyrolysis data using graphs of S2 vs. TOC: Middle Triassic-Lower Jurassic units, eastern part of SE Turkey [J].
Rock–Eval pyrolysis is the most widely used method for screening the petroleum generation potential and thermal maturity of organic rich rocks. In using Rock–Eval pyrolysis to evaluate the properties of organic material within a sedimentary unit, a graph of S 2 (hydrocarbons generated by the pyrolysis, measured in milligrams of hydrocarbon per gram of rock) vs. TOC (total organic carbon content of the rock by percent weight) is an effective tool. It provides the correction for HI (miligrams of hydrocarbon per gram of total organic carbon) and indicates the type of kerogen present, and also measures the adsorption of hydrocarbon by the rock matrix. With the S 2 vs. TOC diagram the organic component of different suites of samples may be compared and their petroleum generation potentials established. As an example, the diagrams are used to evaluate the sedimentary environments and petroleum potential of the Middle Triassic–Lower Jurassic sediments (Bakük, Girmeli, 05amurlu, Telhasan, Din04er, Kozluca and Yola04an Formations) of the eastern part of SE Turkey. The organic material contains about 24 (type III), 27 (type II / III), 33 (type II), 36 (type II), 37 (type II), 23 (type III) and 17 (type III) pyrolyzable hydrocarbons respectively. The positive x-intercept (0.014388) has been calculated only in Yola04an Formation samples according to S 2 vs. TOC diagrams. This value shows a low rock matrix effect. Clay is the main agent of adsorbtion.
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| [87] |
Comparative Rock-Eval pyrolysis as an improved tool for sedimentary organic matter analysis [J].
This new pyrolysis method is proposed mainly for routine analysis of bitumen in rock samples, using a double analysis of each sample (on whole rock and extracted rock). The difference between these two pyrolysis curves corresponds to the bitumen pyrolysis curve and is used for estimating the total bitumen content. The bitumen yield obtained in comparative pyrolysis as a good correlation with the bitumen yield obtained by the standard solvent extraction method with, however, some limitations due to the “mineral matrix effect”. The bitumen pyrolysis curve is further subdivided into three fractions, which allow a quick and easy typing of bitumen products. This method has been successfully applied to basin analysis.
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| [88] |
Comparison and its significance of pyrolysis-gas chromatography characteristics in source rock and clay fraction with diameter <2 μm [J].烃源岩与<2 μm黏粒级组分的热解—色谱特征对比及其意义 [J].
选取济阳坳陷东营凹陷古近系不同埋深的11块烃源岩样品，粉碎后提取粒径小于2μm黏粒级组分，分3个温度段(＜300℃、300～500℃、500～650℃)进行全岩和黏粒级组分样品的热解—色谱检测，探讨不同温度段释放烃的特征和意义，以及黏粒级组分对于烃源岩生烃的贡献。结果表明：在不同温度段，不管是烃源岩全岩还是黏粒级组分，轻质油(C<sub>5</sub>—C<sub>14</sub>)组分在所有组分中含量高，在300℃以前和300～500℃段轻质油组分含量超过50%，而在500～650℃段气态烃(C<sub>1</sub>—C<sub>4</sub>)(特别是甲烷)含量明显增加，而轻质油含量有所下降。在300～500℃段，不论是烃源岩全岩，还是黏粒级组分，生烃产率和产烃量的值都是最高的，其次是500～650℃段，最低的是300℃以前。通过不同温度段特征的比较，发现全岩和黏粒级组分的热解特征有相似之处，轻质油组分是烃源岩热解生烃的主要组分，且300～500℃是烃源岩生烃高峰温度段。对300～500℃段热解—色谱特征进一步研究发现，黏粒级组分的轻烃(C<sub>1</sub>—C<sub>14</sub>)百分含量高于全岩，重烃组分(C<sub>15</sub><sup>+</sup>)则相反，而且黏粒级组分总烃产量占全岩的平均值高达72.57%，这些特征表明黏粒级组分是烃源岩生烃的主要贡献者，且黏土吸附的有机质在有机质生烃过程中对轻烃组分(C<sub>1</sub>—C<sub>14</sub>)的贡献显著。对烃源岩和黏粒级组分开展热解—色谱特征研究，可获取不同温度段释放烃或烃赋存等特征，这对开展有机质生烃和资源评价以及非常规油气赋存特征的研究都具有重要意义。
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| [89] |
Mechanisms of shale gas storage: Implications for shale gas exploration in China [J].
This article reviews the mechanisms of shale gas storage and discusses the major risks or uncertainties for shale gas exploration in China. At a given temperature and pressure, the gas sorption capacities of organic-rich shales are primarily controlled by the organic matter richness but may be significantly influenced by the type and maturity of the organic matter, mineral composition (especially clay content), moisture content, pore volume and structure, resulting in different ratios of gas sorption capacity (GSC) to total organic carbon content for different shales. In laboratory experiments, the GSC of organic-rich shales increases with increasing pressure and decreases with increasing temperature. Under geologic conditions (assuming hydrostatic pressure gradient and constant thermal gradient), the GSC increases initially with depth due to the predominating effect of pressure, passes through a maximum, and then decreases because of the influence of increasing temperature at greater depth. This pattern of variation is quite similar to that observed for coals and is of great significance for understanding the changes in GSC of organic-rich shales over geologic time as a function of burial history. At an elevated temperature and pressure and with the presence of moisture, the gas sorption capacities of organic-rich shales are quite low. As a result, adsorption alone cannot protect sufficient gas for high-maturity organic-rich shales to be commercial gas reservoirs. Two models are proposed to predict the variation of GSC and total gas content over geologic time as a function of burial history. High contents of free gas in organic-rich shales can be preserved in relatively closed systems. Loss of free gas during postgeneration uplift and erosion may result in undersaturation (the total gas contents lower than the sorption capacity) and is the major risk for gas exploration in marine organic-rich shales in China.
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| [90] |
Shale gas potential of the major marine shale formations in the Upper Yangtze Platform, South China, Part II: Methane sorption capacity [J]. |
| [91] |
Geological controls on the methane storage capacity in organic-rich shales [J].
61High-pressure/high temperature methane sorption isotherms measured on gas shales61Samples from Palaeozoic and Mesozoic European and US carbonaceous shale sequences61Measurements performed at different temperatures and defined moisture contents61Correlations tested with total organic carbon (TOC), clay content, maturity (VRr)61Parameters reported for Langmuir-based CH4 excess sorption functions up to 150°C
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| [92] |
Surface wettability of basal surfaces of clay minerals: Insights from molecular dynamics simulation [J].
Understanding the wettability of clay mineral surfaces is crucial for enhancing oil recovery, investigating primary migration of hydrocarbon, and evaluating the performance of sealing rocks in a petroleum system. On the basis of molecular dynamics simulations, we investigated the interactions between four typical clay minerals (i.e., pyrophyllite, montmorillonite, illite, and kaolinite) and confined pore fluids (i.e., water/alkane/salts). The influences of surface group, layer charge, and salts on the wettability of clay surfaces were revealed. As the layer charge increases, the hydrophilicity of the montmorillonite basal surface gradually increases. The basal surface of 2:1-type pyrophyllite is completely alkane-wet independent of salts. However, for 1:1-type kaolinite, the presence of salts makes the siloxane surface completely water-wet, whereas it is partially alkane-wet at the absence of salts. In general, the salt ions adsorbed onto clay surfaces promote the surface hydrophilicity. By using nonequil...
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| [93] |
Effects of organic components on the relationships between specific surface areas and organic matter in mudrocks [J].
61Organic matter (OM) is composed of amorphous and morphological organic matters.61Specific surface areas (SSAs) consist of inner and external surface areas.61Organic component occurrences influence the relationships between OM and SSAs.61This study is important for understanding organic matter occurrences in mudrocks.
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| [94] |
Adsorption of methane and carbon dioxide on gas shale and pure mineral samples [J].
We have measured methane and carbon dioxide adsorption isotherms at 40聽掳C on gas shale samples from the Barnett, Eagle Ford, Marcellus and Montney reservoirs. Carbon dioxide isotherms were included to assess its potential for preferential adsorption, with implications for its use as a fracturing fluid and/or storage in depleted shale reservoirs. To better understand how the individual mineral constituents that comprise shales contribute to adsorption, measurements were made on samples of pure carbon, illite and kaolinite as well. We were able to successfully fit all adsorption data for both gases in accordance with a Langmuir isotherm model. Our results show carbon dioxide to have approximately 2鈥3 times the adsorptive capacity of methane in both the pure mineral constituents and actual shale samples. In addition to obvious microstructural and compositional differences between real rocks and pure minerals, we hypothesize that water adsorption plays an important role in regulating surface area availability for other molecules to adsorb. The resultant volumetric swelling strain was also measured as a function of pressure/adsorption. We observe both clay and pure carbon to swell an amount that is approximately linearly proportional to the amount of adsorption.
|
| [95] |
Influence of soluble organic matter on characterization of shale reservoir [J].可溶有机质对表征页岩储层特性的影响 [J].
成熟度处于"生油窗"范围的页岩含有一定数量的残余可溶有机质,其对页岩储层特性的表征具有重要影响。对取自四川盆地西北缘的2件上二叠统大隆组页岩,采用二氯甲烷与三氯甲烷进行了抽提处理,对去除可溶有机质前、后的页岩开展了有机地球化学、矿物组成、孔隙结构(比表面积、孔容)等储层特性对比研究。结果表明:抽提后样品的TOC、S1、S2、IH等热解参数呈现降低的趋势,但其矿物组分没有变化,保持了页岩原有孔隙结构特征。可溶有机质占据一定孔隙空间,阻碍了孔隙间的连通性。抽提后的页岩测定的比表面积和孔容变大。页岩样品中残余可溶有机质主要分布于微孔及较小的介孔中,并受成熟度水平的制约。对于低成熟度页岩样品,可溶有机质主要赋存于小于5nm有机质孔隙中。对于中等成熟度页岩样品,微孔及小于20nm介孔成为主要的储集空间。
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| [96] |
Note on the mechanical analysis of humus soils [J].
It is generally recognised that the mechanical analysis of soils containing large quantities of organic matter presents considerable difficulties and that in the case of peaty soils mechanical analysis can have little significance. Apart from the masking effect of organic matter on soil properties which will naturally vitiate any correlations with mechanical composition, the actual dispersion of humus soils is difficult owing to the cementing action of humified organic matter, whereby soil particles are aggregated together into compound structures which resist ordinary methods of dispersion. Various methods have been suggested for the destruction of organic matter as a preliminary to mechanical analysis. Atterberg recommends the use of alkaline sodium hypobromite solution. In the case of diatomaceous soils, however, oxidation of the organic matter with hot nitric acid (d. 1u00b714) is recommended. For soils free from calcium carbonate the use of hydrochloric acid (d. 1u00b712) is suggested.
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| [97] |
The determination of organic matter in soils by means of hydrogen peroxide [J].
react-text: 430 Diversos tipos de análise de solo exigem a destrui0400o prévia da matéria org09nica, sendo a água oxigenada o oxidante mais usualmente empregado. Nêste trabalho a a0400o da água oxigenada s00bre o carbono e o nitrogênio do solo foi estudada com pormenores, para esclarecer alguns pontos relativos à oxida0400o. A água oxigenada n00o destroi totalmente a matéria org09nica, qualquer que seja a concentra0400o... /react-text react-text: 431 /react-text [Show full abstract]
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| [98] |
An improved pretreatment for mineralogical analysis of samples containing organic matter [J].
Organic matter removal is accomplished rapidly and efficiently without removing carbonates by treating samples wi~h a sodium hypochlorite solution. Quantities of organic matter lefr in samples by this treatment are commonly less than remain after hydrogen peroxide treatment of acidified samples. Stable suspensions result from the use of a sodium carbonate-sodium bicarbonate solution to wash and sodium saturate the samples without dissolving or complexing sesquioxides.
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| [99] |
A new, efficient, one-step method for the removal of organic matter from clay-containing sediments [J].
For the purpose of clay examination, a new one-step method for the removal of organic matter was developed using sodium peroxodisulphate combined with different buffers such as sodium hydrogen carbonate, disodium hydrogen phosphate and disodium tetraborate. From an early Cretaceous black shale from the Apennines with a high organic carbon content, the <2 渭m clay fraction was separated and contained 10.9 wt% organic carbon. To prevent decomposition of the clay layers, the period of oxidation was short (25-60 min) and the pH was kept between 5 and 9.5. Up to 98% of carbon was removed by this method.
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| [100] |
Organic matter-surface area relationships in acid soils [J].
Soil organic matter (OM) and mineral surfaces are intimately related, affecting the dynamics of each and their reactivity with many environmentally important substances, We examined the coverage of mineral surfaces by OM in acid soils of Massachusetts. Specific surface areas are controlled by a combination of clay and sesquioxide contents. Subsurface horizons, especially C horizons with pH 4.6 to 4.8, contained a phase with significant microporosity (pores <2 nm) that could be eliminated by 350 degreesC muffling, Organic C (OC) concentrations in surficial (A, O) horizons have surface area-normalized loadings usually above the monolayer-equivalent (ME) level (approximate to1 mg OC m(-2)), while B and C horizons usually have loadings at this level. Surface area-normalized loadings are inversely related to pH for each horizon type. Samples with high loadings show occlusion of the bulk of mineral surface area by OM, as evidenced by release of significant surface area after OM removal, However, a new method of assessing OM coverage of exposed surfaces, using the energetics of gas adsorption, indicate that the bulk of surface area exposed in most untreated samples consists of mineral rather than organic material. The data are consistent,vith a model in which the occluding OM is present in a low-surface area configuration, such as organoclay aggregates, rather than as dispersed coatings on mineral grains.
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| [101] |
Oxidative degradation of MTBE by pyrite-activated persulfate: Proposed reaction pathways [J].
This bench-scale study investigated the feasibility of activated persulfate (S(2)O(8)(2-)) oxidation of methyl tertbutyl ether (MTBE), using pyrite (FeS(2)) as the source of ferrous ion activators. Under the FeS(2)-activated S(2)O(8)(2-) condition, the sulfate free radical (SO(4)) is the predominant reactive species generated. The oxidation reactions were able to completely degrade MTBE when given sufficient doses of FeS(2) and S(2)O(8)(2-) and sufficient reaction time (e.g., 3 g FeS(2)/L and 5 g Na(2)S(2)O(8)/L within 4 h) and exhibited generation and subsequent degradation of the primary MTBE degradation intermediate products including tert-butyl formate, tert-butyl alcohol, methyl acetate, and acetone. The detailed reaction mechanism proposed for a SO(4)(-)driven oxidation process in this paper indicates that the destruction of MTBE most likely happens through alpha-hydrogen abstraction via attack of the SO(4)(-) at the intermediate methoxy group.
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| [102] |
Persulfate activation by naturally occurring trace minerals [J].
The potential for 13 naturally occurring minerals to mediate the decomposition of persulfate and generate a range of reactive oxygen species was investigated to provide fundamental information on activation mechanisms when persulfate is used for in situ chemical oxidation (ISCO). Only four of the minerals (cobaltite, ilmenite, pyrite, and siderite) promoted the decomposition of persulfate more rapidly than persulfate鈥揹eionized water control systems. The other nine minerals decomposed persulfate at the same rate or more slowly than the control systems. Mineral-mediated persulfate activation was conducted with the addition of one of three probe compounds to detect the generation of reactive oxygen species: anisole (sulfate + hydroxyl radical), nitrobenzene (hydroxyl radical), and hexachloroethane (reductants and nucleophiles). The reduced mineral pyrite promoted rapid generation of sulfate + hydroxyl radical. However, the remainder of the minerals provided minimal potential for the generation of reactive oxygen species. The results of this research demonstrate that the majority of naturally occurring trace minerals do not activate persulfate to generate reactive oxygen species, and other mechanisms of activation are necessary to promote contaminant destruction in the subsurface during persulfate ISCO.
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| [103] |
Stabilization of soil organic matter: Association with minerals or chemical recalcitrance? [J].
Soil organic matter (OM) can be stabilized against decomposition by association with minerals, by its inherent recalcitrance and by occlusion in aggregates. However, the relative contribution of these factors to OM stabilization is yet unknown. We analyzed pool size and isotopic composition (0166C, 0106C) of mineral-protected and recalcitrant OM in 12 subsurface horizons from 10 acidic forest soils. The results were related to properties of the mineral phase and to OM composition as revealed by CPMAS 0106C-NMR and CuO oxidation. Stable OM was defined as that material which survived treatment of soils with 6 wt% sodium hypochlorite (NaOCl). Mineral-protected OM was extracted by subsequent dissolution of minerals by 10% hydrofluoric acid (HF). Organic matter resistant against NaOCl and insoluble in HF was considered as recalcitrant OM. Hypochlorite removed primarily 0166C-modern OM. Of the stable organic carbon (OC), amounting to 2.4-20.6 g kg6301 soil, mineral dissolution released on average 73%. Poorly crystalline Fe and Al phases$(\text{Fe}_{\text{o}},\text{Al}_{\text{o}})$and crystalline Fe oxides$(\text{Fe}_{\text{d}-\text{o}})$explained 86% of the variability of mineral-protected OC. Atomic$\text{C}_{\text{p}}/(\text{Fe}+\text{Al})_{\text{p}}$ratios of 1.3-6.5 suggest that a portion of stable OM was associated with polymeric Fe and Al species. Recalcitrant OC (0.4-6.5 g kg6301 soil) contributed on average 27% to stable OC and the amount was not correlated with any mineralogical property. Recalcitrant OC had lower Δ0166C and δ0106C values than mineral-protected OC and was mainly composed of aliphatic (56%) and O-alkyl (13%) C moieties. Lignin phenols were only present in small amounts in either mineral-protected or recalcitrant OM (mean 4.3 and 0.2 g kg6301 OC). The results confirm that stabilization of OM by interaction with poorly crystalline minerals and polymeric metal species is the most important mechanism for preservation of OM in these acid subsoil horizons.
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| [104] |
Sodium hypochlorite separates an older soil organic matter fraction than acid hydrolysis [J].
Different chemical treatments can be used to isolate an old and chemically resistant soil organic matter fraction from soils. Here, we compared the residues after acid hydrolysis (6聽N HCl) with those obtained after NaOCl treatment (6聽wt%) of the silt + clay fractions from 48 soil samples. The samples were taken at sites differing in climate and land use across Switzerland. To determine the influence of the two treatments on soil organic matter and mineral structures, we examined infrared spectra and isotopic signatures of carbon ( 14C and 未 13C) of the residues. Treatment with NaOCl removed more (63 to 91%) organic carbon (OC) than did treatment with HCl (35 to 66%), and it had no effect on mineral structures, whereas treatment with HCl converted crystalline minerals to more amorphous ones. Increases in specific soil surface area (SSA) did not correlate with the amount of OC removed. The amount of OC removed by each treatment was not (NaOCl) or only weakly (HCl) related to the initial OC content of the silt + clay fraction, suggesting the presence of a relatively constant fraction of chemically resistant OC. 14C activities of NaOCl-resistant residues were lower than those of HCl residues, indicating that soil organic matter residues isolated by NaOCl treatment were older than the residues obtained by acid hydrolysis. It is concluded that oxidation with NaOCl is the better way than hydrolysis with HCl to obtain an operationally-defined stable organic matter fraction from soils.
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| [105] |
Organic matter in small mesopores in sediments and soils [J].
The three-way correlation among organic matter concentrations, specific surface area and small mesopores observed for many soils and sediments led to the hypothesis that enclosure within the pores might explain the apparent protection of organic matter by minerals. We test this hypothesis by examining whether the bulk of organic matter resides within small mesopores. Pore volumes as a function of pore width were measured before and after organic matter removal, and the volume differences ascribed to organic matter filling of pores. Minor changes in small mesopore size distributions upon treatments such as centrifugation and muffling indicate the robustness of the mineral matrices that form these pores. We developed an additional method to assess organic matter densities using high-resolution pycnometry, and used these densities to convert pore volumes to organic matter contents. Although smaller mesopores are shown to have sufficient volumes to contain significant fractions of the total organic matter, only small fractions of total organic matter were found to reside in them. These results are consistent with preferential association between organic matter and aluminous clay particle edges, rather than the largely siliceous clay faces that contribute most surface area and form pore walls. While simple enclosure within smaller mesopores cannot, therefore, explain protection, network effects working at larger size scales may account for exclusion of digestive agents and hence organic matter protection.
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| [106] |
Extent and nature of organic coverage of soil mineral surfaces assessed by a gas sorption approach [J].
Organic matter (OM) in soils often associates intimately with the surfaces of fine-grained minerals. We used two measures of OM–mineral associations, based on either the energetics of N 2 gas sorption (C-constant in BET equation) or changes in mineral specific surface area (SSA) upon removal of OM, that provide complementary information on organic coverage of mineral surfaces. Undisturbed surface mineral soils along an altitudinal transect in Borneo provided a gradient of OM levels (30 to 140mg-OC g 61021 soil) with which to address modes of mineral surface coverage by OM, and were compared with a variety of soils throughout the USA. Increasing OM levels, either as OM content or as a ratio to SSA (i.e. loading), led to coverage of the mineral surfaces proportional to the OM content. In all surface horizon samples from Borneo and the USA, cross-plots of the two measures show that these surfaces were covered by OM having low SSA (presumably in globular forms) rather than thin coatings of adsorbed OM. The latter mode was found only in some podzolic B-horizon samples. At loadings of >023–4mg-OC m 61022 , virtually all mineral surfaces in soils derived from aluminosilicate parent materials were covered by OM. Iron-rich soils on ultrabasic parent material did not achieve this full coverage. At loadings <022–3mg-OC m 61022 , exposed surfaces of the soils were dominantly mineral even though 10–70% of total mineral surface was inaccessible to N 2 gas due most likely to organic occlusion of the mineral phases that have high SSA. These modes of OM-surface coverage may have important implications for aqueous–solid reactions in soil.
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| [107] |
Porosity evolution in oil-prone source rocks [J].
The PSD and SSA measured after each extraction shows recovery of the pore system with successive cleaning. Most significant was the recovery of kerogen-hosted pores with removal of soluble, oil-like organic material. Using successive extractions we are able to determine the evolution of organic matter porosity through maturation which is otherwise not feasible using visual techniques or other conventional laboratory procedures.
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| [108] |
Specific surface area of clay minerals: Comparison between atomic force microscopy measurements and bulk-gas (N2) and-liquid (EGME) adsorption methods [J]. |
| [109] |
Microstructural investigation of gas shales in two and three dimensions using nanometer-scale resolution imaging [J]. |
| [110] |
Comparison of low-field NMR and mercury intrusion porosimetry in characterizing pore size distributions of coals [J].
In this study we investigated how traditional mercury intrusion porosimetry (MIP), constant-rate-controlled mercury porosimetry (CMP), Low-field NMR spectral analysis (LFNMR), and micro focus computerized tomography (渭CT) compare in revealing the pore size distribution (PSD) characteristics of coals. The comparison was made using the same source samples throughout. Two limitations of mercury porosimetry are addressed. First, the high-pressure intrusion by mercury may either deform or destroy the coal sample and eventually induce suspect value of coal porosity, thus correction of pore structure compressibility must be made in analyzing lignite or other coals that with very open structure. Second, pore shielding effects can induce high uncertainty of MIP results, in particular when clusters of smaller pores occur in isolated domains in a continuous network of larger pores. This can result in temporary mercury entrapment during the extrusion process and result in inaccurate estimations of PSD. Another pore shielding effect is due to isolated clusters of large pores in a continuous network of smaller pores. Her mercury is prone to be trapped permanently. This effect can induce inaccurate estimations of the total pore volume. CMP is an effective method that can provide much more detailed PSD information of macropores, however it is deficient in analyzing mesopores of coals. After comparison with the results by 渭CT and other traditional methods, it was found that LFNMR is an efficient tool for nondestructively quantifying the PSD of coal.
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| [111] |
BIB-SEM study of the pore space morphology in early mature Posidonia Shale from the Hils area, Germany [J].
78 BIB milling gives access to 2D pore space in undamaged, mm2 areas. 78 BIB-SEM allows qualitative and quantitative study of porosity down to 10nm. 78 Pore areas are power law distributed. 78 Comparison of BIB-SEM analysis with MIP exemplifies the pore connectivity.
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| [112] |
Characterization of pore systems in seal rocks using nitrogen gas adsorption combined with mercury injection capillary pressure techniques [J].
Porous microstructure parameters of seal rock samples originating from different depths within Brazilian geological formations were correlated to empirical models which predict the intrinsic permeability. Mercury Injection Capillary Pressure (MICP) and Nitrogen Gas Adsorption (N(2)GA) were applied in combination as complementary techniques; MICP to obtain the porosity values and the size distribution of meso- and macropores, and N(2)GA associated with the Brunauer, Emmett and Teller (BET) theory to determine the specific surface area (S-0). The Barret, Joyner and Hallenda (BJH) theory was applied to find the size distribution of the micro- and mesopores. The combination of the MICP and N(2)GA curves showed that the samples analyzed present a polymodal pore size distribution (PSD) and a total porosity ranging from 0.33 % to 10.44 %. The S-0 values measured by N(2)GA were higher than those calculated by MICP, due to the majority of the samples having a mean pore size of 20-1000 A. The intrinsic permeability could also be predicted applying the measured parameters, S-0, PSD curves and total porosity in the Carman-Kozeny and Series-Parallel models. The ranges of permeability values obtained were 4.09 x 10(-24)-4.96 x 10(-21) m(2) and 9.48 x 10(-27)-9.14 x 10(-22) m(2), respectively. These results were compared with values reported in the related literature and those obtained for four samples submitted to pressure pulse decay permeability (PDP) tests. (c) 2012 Elsevier Ltd. All rights reserved.
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| [113] |
Characterization of oil shale pore structure before and after pyrolysis by using X-ray micro CT [J].
The pyrolysis of oil shale to produce transportation fuels is a complex process. The organic matter in the oil shale is tightly bound with a heterogeneous mineral matrix. Several physical changes occur during the thermal conversion of kerogen in oil shale to produce hydrocarbon products. The creation of pore space during pyrolysis is an important physical process which determines the flow behavior of the pyrolysis products and the ultimate recovery. In this paper, we report the effect of temperature (350–500°C) on oil shale pyrolysis and creation of pore volume during thermal treatment. One inch diameter oil shale cores from different depths of a single drill hole in the Uinta Basin were used. Increase in the pyrolysis temperature resulted in higher weight loss and a corresponding increase in the oil yield. Three-dimensional X-ray micro tomography (XMT) was performed to characterize and to analyze the nature of the pore network structure before and after pyrolysis. XMT scans of the cores at 42μm voxel resolution displayed distinguishable features of reaction products and source rock. Unconstrained pyrolysis of organic rich core produced large pore space during thermal treatment. The three-dimensional pore network structure was established with pores as large as 500μm developed after pyrolysis. Lattice Boltzmann simulation of flow through the developed pore network structure suggested that permeabilities from 173 Darcy to 2919 Darcy can be expected.
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| [114] |
Qualitative and quantitative characterization of shale microscopic pore characteristics based on image analysis technology [J].基于图像分析技术的页岩微观孔隙特征定性及定量表征 [J].
在有限的条件下,为了更经济有效地评价页岩微观孔隙特征,同时利用扫描电镜(SEM)、氩离子抛光场发射扫描电镜(FESEM)方法对四川盆地彭水地区龙马溪组页岩孔隙特征进行了定性观察,并借助专业的图像分析软件IamgeJ2x 提取页岩SEM和FESEM图像蕴含的孔隙定量信息,结合统计学方法分析页岩全孔径分布特征,计算页岩孔隙分形维数,探讨孔隙结构特征以及分析维数与有机碳含量、矿物成分、孔隙吸附能力等的相关性,研究发现:扫描电镜下,彭水地区龙马溪组页岩微米级孔隙发育,主要孔隙类型有粒间孔、黏土矿物层间孔、粒内孔以及微裂缝等;氩离子抛光场发射扫描电镜下,可见大量纳米级孔隙,主要发育有机质孔、无机矿物孔(黄铁矿晶间孔、粒内孔、黏土矿物层间孔、粒间孔等)和微裂缝,两者综合分析更有利于页岩孔隙定性表征;页岩孔隙全孔径分布特征呈4个主峰,主要分布区间为3~9 nm,10~40 nm,100~400 nm,1~4 μm;页岩有机质孔隙形状系数分布区间为0.9~1,孔隙呈圆形、近圆形,无机矿物孔形状系数分布在0.5~0.7,多呈三角形、多边形、狭缝形等,孔隙形状较有机质孔复杂,主要受页岩孔隙成因不同所致;彭水地区龙马溪组页岩孔隙符合分形特征,有机质孔隙分形维数较无机矿物孔分形维数小,孔隙结构相对简单;分形维数与有机质含量、矿物成分、孔隙度及吸附气含量都有一定的相关性,随有机质含量的增加,孔隙分形维数增加,孔隙结构复杂化,随分形维数增加,页岩孔隙的最大吸附气含量也随之增加,孔隙吸附能力增强。
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| [115] |
The determination of pore volume and area distributions in porous substances. I. Computations from nitrogen isotherms [J].
The Determination of Pore Volume and Area Distributions in Porous Substances. I. Computations from Nitrogen Isotherms
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| [116] |
An improved method for the calculation of pore size distribution from adsorption data [J].
A method for calculating the pore size distribution from adsorption isotherms on porous solids is described, which is more exact and less tedious to use than some previously described methods. The method of compiling tables for calculation is shown and an example of such a calculation is given.
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| [117] |
Method for the calculation of effective pore size distribution in molecular sieve carbon [J].
Abstract A method for the calculation of effective pore size distribution from adsorption isotherms in molecular-sieve carbon is described. This method is more exact theoretically as well as practically than previously described methods. An average potential function has been determined inside the slit-like pores. With the help of this function the doubtful use of the Kelvin equation can be avoided at the scale of molecular dimensions. The method gives poor values for the larger pores but can be combined with the well-known Dollimore-Heal method at a pore size of 1. 34 nm. Calculation is possible over a wide range of pore sizes. The calculation is shown through two examples from N//2 isotherms at 77. 4K. The model can be extended to other pore shapes as well as to other adsorbent-adsorbate pairs.
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| [118] |
Curvature and parametric sensitivity in models for adsorption in micropores [J].
The sensitivity of the calculated micropore size of zeolite Y in a fluidized cracking catalyst based on empirical models for argon adsorption has been tested by examining the effect of curvature and by systematically verifying the magnitude of physical constants in the model equations. With a consistent set of physical parameters the slit model provided a pore size value of 0.45 nm, while the new cylindrical models provided values of 0.69 and 0.74 nm. The latter values are found to correspond well with the known aperture size of zeolite Y, 0.74 nm. By separately varying the magnitudes of five of the physical constants in the model over a range of 卤30%, it was concluded that the diameter of the oxide ion at the surface had a large effect on the calculated pore size, while the other parameters had only moderate to small effects. Preliminary application of the cylindrical pore model to isotherms of argon on other zeolites and molecular sieves leads to promising results, especially for medium to large pore zeolites. These results suggest that the cylindrical pore model is a useful means for the transformation of argon adsorption data on a zeolite into a micropore size distribution.
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| [119] |
Variation in micropore capacity and size distribution with composition in bituminous coal of the Western Canadian Sedimentary Basin: Implications for coalbed methane potential [J].
The effects of lithotype, maceral and mineral contents on the micropore capacity and size distribution are investigated for a medium-volatile bituminous coal from the mid-Cretaceous Gates Formation of north-east British Columbia and a high-volatile bituminous coal from the Cretaceous of Alberta. Vitrinite content (vol.% mmf) ranges from 18 to 95 for the Gates coal and 36 to 85 for the Alberta coal. Ash yields (wt%) vary from 4.4 to 33.7 for the Gates coal and 1.2 to 10.6 for the Alberta coal. Dubinin-Radushkevich CO
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| [120] |
Pore size determination in modified micro-and mesoporous materials. Pitfalls and limitations in gas adsorption data analysis [J].
Physical gas adsorption is extensively used in the characterization of micro- and mesoporous materials and is often considered as a straightforward-to-interpret technique. However, physical phenomena like the tensile strength effect, adsorbate phase transitions, and monolayer formation in combined micro- and mesoporous materials frequently lead to extra contributions in the adsorption isotherm. Models for pore size determination mostly do not account for this, and assignment to real pores leads to improper analysis of adsorption data. In this review, common pitfalls and limitations in the analysis of pore size distributions derived from adsorption isotherms of micro- and mesoporous materials are identified and discussed based on new results and examples reported in the recent literature.
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| [121] |
Contrast of nitrogen adsorption method and mercury porosimetry method in analysis of shale’s pore distribution [J].氮气吸附法和压汞法在测试泥页岩孔径分布中的对比 [J].
泥页岩比表面大，孔隙小，结构复杂，易吸水膨胀，一般方法很难准确描述其孔径分布情况。对泥页岩孔径分布的研究在石油钻井，完井，储层描述，泥页岩盖层封闭性等方面有着重要的意义。实验分别使用氮气吸附法和压汞法对同一泥页岩进行孔径分析。氮气吸附法中使用BJH 原理分析泥页岩的中孔径，使用DA原理分析泥页岩的微孔径；压汞法中使用Wasburn公式分析泥页岩整体孔隙，对两种方法实验结果进行对比。氮气吸附法在泥页岩微孔和中孔分析方面有优势，能分别对泥页岩的微孔和中孔进行详细的描述；而压汞法受泥页岩孔径分布不均一性影响相对较小，能弥补氮气吸附法在大孔分析方面的不足。把氮气吸附法和压汞法测得的孔径分布结果结合使用，可以得到泥页岩从微孔到大孔的孔径分布情况。
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| [122] |
Determination of organic-rich shale pore features by mercury injection and gas adsorption methods [J].压汞法和气体吸附法研究富有机质页岩孔隙特征 [J].
页岩储层孔隙由宏观裂缝到微观纳米级孔隙构成,具有较低的孔隙度。为了对页岩孔隙进行有效分析,将页岩中的孔隙分为3类并分别运用相应的方法对其进行测定：①页岩中的微孔（〈2nm）应用CO2低温吸附法（D-R方法）测定;②介孔（2～50nm）应用N2低温吸附法（BET理论）测定;③宏孔（〉50nm）应用高压压汞法测定,进而对孔隙分布进行全面分析。利用以上方法对中国典型海相和湖相页岩孔隙进行测定并分析孔隙发育控制因素后发现：①四川盆地海相页岩孔隙发育,其中牛蹄塘组、五峰组较好;②页岩中宏孔主要与矿物相关,微孔、介孔主要与有机质相关;③随着热演化程度升高,页岩中有机孔隙逐渐增大。
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| [123] |
Classifying coal pores and estimating reservoir parameters by nuclear magnetic resonance and mercury intrusion porosimetry [J].
The widely used coalbed methane (CBM) flow model-triple porosity/dual permeability (TPDP) model indicates that coal pores can be divided into micro-trans-pores, meso-macro-pores, and fractures, while CBM can flow via meso-macropores and fractures. The mechanism to obtain the reservoir parameters of these two flowing systems has been given little attention in the TPDP model. In this study, nuclear magnetic resonance (NMR), mercury intrusion porosimetry (MIP), and other routine core analysis methods were conducted on nine coal samples to classify coal pore types, transform transverse relaxation time to pore radius, and estimate porosity and permeability of meso-macro-pores and fractures. Results show that the two referenced relaxation times of T-2C1 and T-2C2, which were identified from the curves of irreducible and full water saturations obtained from NMR experiments, can classify coal pores into fractures (T-2 > T-2C2), meso-macro-pores (T-2C1 < T-2 < T-2C2), and micro-trans-pores (T-2 < T-2C1). The dividing point of micro-trans-pores and meso-macro-pores, which was obtained from NMR and MW (mercury intrusion porosimetry) experiments, provided another method for transforming transverse relaxation time to pore radius. Based on the classification results and routine core analysis methods, the porosity of meso-macro-pores and fractures were calculated, and the relationship between air permeability and porosity of meso-macro-pores and fractures was finally proposed. This paper provides an effective method for obtaining the permeability and porosity of meso-macro-pores and fractures using the TPDP model to simulate the performances of CBM wells.
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| [124] |
Determination of surface area of fine-grained soils by the Ethylene Glycol Monoethyl Ether (EGME) method [J].
This paper describes a test procedure for determining the total surface area of fine-grained soils using the Ethylene Glycol Monoethyl Ether (EGME). The test involves saturating a soil sample with EGME and then removing the excess EGME in a vacuum desiccator, until the EGME forms a monomolecular layer on the soil surface. The results of the test are expressed as Specific Surface Area (SSA), which describes the surface area/unit mass of dry soil with units of m2/g. Test results are presented demonstrating the effect of various test parameters on the results. Results for a number of different fine-grained soils are presented. A detailed recommended test procedure is given. The proposed method uses simple and inexpensive laboratory equipment, is relatively simple to perform, and allows for rapid determination of SSA.
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| [125] |
Surface area and layer charge of smectite from CEC and EGME/H2O-retention measurements [J]. |
| [126] |
Method dependency of relationships between specific surface area and soil physicochemical properties [J].
It is postulated that the behavior of fine-grained soils may be explained by the relationship between surface area and other geotechnical properties. To this end, there are several studies correlating geotechnical indexes with specific surface area (SSA). However, there is no universally accepted specific surface area determining method as several methods are available. Depending on the method employed, the measured specific surface area may show variations for a given soil. This is because the predictive power of each method depends on the type of minerals and organic matter that are present in the soil. Thus, different SSA determination methods yield widely different estimates of index properties and regression equations. To examine the role of method on SSA of soils, the SSAs of 32 soils with different mineralogies were determined using BET-N 2 , EGME, MB-titration, and MB-spot test methods. The measured SSA of soils was correlated with their respective geotechnical index properties. Further, the data obtained in this study and those reported by previous researchers were compared. The results suggest that correlations between geotechnical index properties and SSA using different methods may not be comparable. Accurate prediction, however, is provided only if the relationship is calibrated using soils having similar physical and chemical characters.
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| [127] |
Adsorption of gases in multimolecular layers [J]. |
| [128] |
Sorption of nitrogen and Ethylene Glycol Monoethyl Ether (EGME) vapors on some soils, clays, and mineral oxides and determination of sample surface areas by use of sorption data [J].
Vapor sorption isotherms of ethylene glycol monoethyl ether (EGME) at room temperature and isotherms of N2 gas at liquid nitrogen temperature were determined for various soils and minerals. The N2 monolayer capacities [Qm (N2)] were calculated from the BET equation and used to determine the surface areas. To examine whether EGME is an appropriate adsorbate for determination of surface areas, the apparent EGME monolayer capacities [Qm (EGME)ap] were also obtained by use of the BET equation. For sand, aluminum oxide, kaolinite, hematite, and synthetic hydrous iron oxide, which are relatively free of organic impurity and expanding/solvating minerals, the Qm (EGME)ap values are in good conformity with the corresponding Qm (N2) values and would give surface areas consistent with BET (N2) values. For other samples (Woodburn soil, a natural hydrous iron oxide, illite, and montmorillonite), the Qm (EGME)ap values overestimate the Qm (N2) values from a moderate to a large extent, depending on the sample. A high-organic-content peat shows a very small BET (N2) surface area; the EGME/ peat isotherm is linear and does not yield a calculation of the surface area. Large discrepancies between results of the two methods for some samples are attributed to the high solubility of polar EGME in soil organic matter and/ or to the cation solvation of EGME with solvating clays. The agreement for other samples is illustrative of the consistency of the BET method when different adsorbates are used, so long as they do not exhibit bulk penetration and/or cation solvation. ?? 1993 American Chemical Society.
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| [129] |
Comparison of methods for determining specific surface area of soils [J]. |
| [130] |
Discussion on the method for determining BET specific surface area in argillaceous source rocks [J].
Samples of argillaceous source rocks were taken at different depth in Dongying Sag and pretreated with different methods. Contrastive analysis to those samples by using N2 adsorption, pyrolysis, X-ray diffraction detection has been made, so as to discuss the validity and credibility of the detection method for specific surface area (SSA), and work for the study on shale gas preservation characteristics. The source rocks were treated with hydrogen peroxide and chloroform. It is found that the average TOC content in the source rock samples treated with hydrogen peroxide decreased than that of the original sample by 61.3% on average for the removal of organic matter in particle state and surface adsorption state, whereas decreased by 20.9% in the samples treated with chloroform for the dissolved organic matter (organic matter in intergranular pores and physical adsorbed) removal, accordingly, the average BET specific surface area increased by 77.5% in the samples treated with hydrogen peroxide than that of the original sample, whereas increased by 22.0% in the samples treated with chloroform, which shows that the organic matter on the specific surface of source rocks can be effectively removed and BET specific surface area extended both with chloroform and hydrogen peroxide treatment. Nonetheless, further analysis shows that the samples treated with chloroform contain the same mineral compositions as the original samples, while the samples treated with hydrogen peroxide have considerably different mineral compositions from the original samples, thus breaking up the original rock structure and the mineral content of the source rocks. Based on the study and analysis above, it is the best choice to select the chloroform treatment to the bulk rock samples for detecting the BET specific surface area, which is possible not only to effectively remove organic matter but also keep the original mineral structure of the rock, thus obtaining true in situ external specific surface area of source rocks, and providing reliable parameters for the study of shale gas occurrence state.
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| [131] |
Discussion on an evaluation method of shale oil and gas in Jiyang depression: A case study on Luojia area in Zhanhua sag [J].济阳坳陷页岩油气评价方法——以沾化凹陷罗家地区为例 [J]. |
| [132] |
Adsorption of mudstone source rock for shale oil—Experiments, model and a case study [J].
Inorganic minerals were separated from mudstone and shale to investigate their oil adsorption potential. A conceptual model was developed to reconstruct the oil adsorption capacity of underground mudrock/shale by combining adsorption and organic matter swelling data. The predictions for the free hydrocarbon oversaturation sorption zones in the Well NY1 profile were taken as a case study. The results suggest that the best depth for the shale oil prospect of the Es4s member strata lies between 3400 and 3600m in the Dongying Depression. Hydrocarbon starvation zones occur mainly at a depth of <3400m, where both the maturity and the extent of oil conversion of organic matter are relatively low, while the sorption capacity of mudstone and shale rocks is by comparison high and the exploration risk is greater.
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| [133] |
Pore characteristics of continental shale and its impact on storage of shale oil in northern Songliao Basin [J].松辽盆地北部陆相泥页岩孔隙特征及其对页岩油赋存的影响 [J].
综合应用气体吸附、高压压汞和扫描电镜方法对松辽盆地白垩系陆相泥页岩内部微观孔隙特征进行刻画,进而结合岩石热解、全岩矿物分析等实验手段对泥页岩孔隙发育的控制因素及其对含油性的影响进行分析。结果表明:研究区泥页岩孔隙类型以片状黏土矿物的层间微孔隙为主,裂缝发育程度不高,孔隙级别以微孔和介孔为主,泥页岩孔隙发育总体受控于埋深和次生孔隙发育情况,有机孔隙对页岩油储层不具有重要意义;油源充足的情况下,泥页岩含油性明显受控于孔隙度,其中直径大于20 nm孔隙是页岩油的主要赋存空间,在进行页岩油勘探开发时应着力寻找较大孔隙发育的甜点区;龙虎泡阶地南部与齐家-古龙凹陷交界处青山口组含砂岩或砂质薄夹层的泥页岩层系中泥岩次生孔隙发育,含油性高,易于压裂,是松辽盆地北部页岩油勘探开发的首选区域。
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