近年来,随着油气资源增长的需求和勘探理论方法的深入,深达5 000~8 000 m深层、超深层碎屑岩储层日益成为油气勘探的新领域。20世纪70年代末以来,我国对深层、超深层碎屑岩储层的研究已经开展了几十年,取得了一系列重大发现。在我国典型盆地大地构造背景和沉积环境影响下,深层、超深层碎屑岩储层经历了长期的埋藏、压实和溶蚀等作用,通常物性较好而形成有效储层。因此,有效储层形成的主控因素成为深层、超深层碎屑岩领域研究关注的焦点。研究发现:① 深部溶蚀作用是深层、超深层碎屑岩有效储层形成的普遍机理,主要通过有机质成熟产生的有机酸和无机酸等对粒间碳酸盐胶结物和长石、岩屑等易溶组分的溶蚀,从而形成次生孔隙。② 地温梯度越低,成岩强度越弱,砂岩孔隙度衰减速率越慢;早期长期浅埋、晚期快速深埋的过程能够有效保存原生孔隙。③ 异常压力能够延缓岩石受到的压实作用,抑制有机酸排出而有利于深层、超深层储层形成次生孔隙。④ 膏盐层会延缓成岩作用进程,形成物性和压力双重封闭,有利于膏盐层下砂岩孔隙的保存。⑤ 黏土膜如绿泥石黏土膜等,对深层、超深层碎屑岩储层高孔隙度的保存具有重要贡献。⑥ 成岩压实作用、早期烃类充注及碎屑颗粒成分等因素也会对有效储层的形成产生影响。对深层、超深层储层油气地质研究,要立足于陆上,加强海洋特别是深水区域油气勘探工作,同时要进一步加强油气地质勘探理论和勘探技术的创新。

In recent years, with increasing demand for oil and gas, and advances in exploration methods, deep and ultra-deep (5 000~8 000 m) clastic reservoirs have become a new domain for oil and gas exploration. Research on deep and ultra-deep clastic reservoirs began in the 1970s and has achieved a series of major findings. Under the typical tectonic setting and sedimentary environment of basins in China, deep and ultra-deep clastic reservoirs, having experienced long-term burial, compaction, and dissolution, generally possess good physical properties and have become effective reservoirs. Therefore, the main controlling factors on the formation of such reservoirs have become the focus of research on deep and ultra-deep clastic rocks. Previous studies in this field have made the following findings. ①Dissolution is a general mechanism for the formation of effective deep and ultra-deep clastic reservoirs. Specifically, the organic and inorganic acids generated by organic matter maturation act to dissolve soluble carbonate cement components such as feldspar and lithic fragments, forming secondary pores. ②The lower the geothermal gradient and weaker the intensity of diagenesis, the slower the decrease in sandstone porosity. Thus, the process of long-term early stage shallow burial and rapid late-stage deep burial is conducive to the preservation of primary porosity. ③Anomalous pressure can delay the compaction of rock, inhibiting the expulsion of organic acids that are favorable for the generation of secondary pores in deep and ultra-deep reservoirs. ④Gypsum layers can slow the process of diagenesis, forming dual sealing by physical properties and pressure. This is conducive to the preservation of porosity in sandstone located below the gypsum layer. ⑤Clay film (e.g., chlorite film) also plays an important role in preserving the porosity of deep and ultra-deep clastic reservoirs. ⑥The formation of effective reservoirs also can also be influenced by the factors of diagenetic compaction, early hydrocarbon filling and clastic particles composition. Geologic research on deep and ultra-deep reservoirs should focus on reservoirs on land as this will strengthen our understanding of offshore reservoirs, especially in deep waters. Moreover, further innovation in theory and technology of oil and gas exploration are required.