滨浅湖环境中广泛发育砂—泥沉积记录,油气生储盖组合配置较好,具有重要的油气地质意义。以济阳坳陷始新统孔店组为例,对滨浅湖环境中砂—泥沉积记录的形成机制及成岩系统进行研究。结果表明:济阳坳陷孔店组宏观上表现为砂—泥对偶、脉状泥岩和砂岩透镜体等3种砂—泥互层沉积层系;微观上主要为各种砂—泥过渡碎屑岩,含碎屑颗粒、黏土和碳酸盐等3种结构组分。砂泥互层沉积层系主要受控于浅水型三角洲侧翼的物质改造和滨浅湖环境中的共轭震荡,厚度受物质来源和水动力条件等制约;砂—泥过渡碎屑岩类主要跟水体动力机制和沉积分异作用有关。砂—泥互层沉积层系组成封闭性的成岩系统,泥岩成岩过程的早期压实排水和差异压实作用、中晚期黏土矿物转化、结构水和有机酸的排放制约砂岩层的成岩作用,而砂—泥过渡岩类封闭成岩系统主要受碎屑岩结构成熟度的制约。

The sand-mud sedimentary record develops widely in the shore-shallow lacustrine, which can be a good oil and gas reservoir cap combination. It has important significance in petroleum geology. This paper takes the Kongdian Fm. of Eocene in Jiyang Depression as an example to study the formation mechanism and diagenetic system of the sand-mud sedimentary record in the shore-shallow lacustrine. The study indicated that sandstone-mudstone sedimentary strata at macroscopic level includes sand-mud duality, mudstone vein and sandstone lens in the Kongdian Fm. of Jiyang Depression, and there are some transitional clastic rocks at the microscopic level (Clastic particles, clay and carbonate cements are included in the transitional clastic rocks). The sandstone-mudstone sedimentary strata mainly formed in the material transformation of the shallow-water deltas and conjugate shock in the shore-shallow lacustrine. The thickness is mainly restricted by material source and water dynamic condition, and the sand-mud transitional clastic rocks are restricted by the dynamic mechanism and sedimentary differentiation of the lake water. The sandstone-mudstone sedimentary strata is composed of a closed diagenetic system. Early compaction-drainage and differential compaction, middle and late clay mineral transformation, structural water and organic acid emissions during the diagenetic process of mudstone influence the diagenesis of sandstone. The closed diagenetic system of sand-mud transitional clastic rocks is mainly related to the structural maturity of clastic rocks.