致密碎屑岩中粘土矿物的形成机理与分布规律

随着油气勘探开发的逐渐深入，深层致密碎屑岩油气藏所占比例越来越高。致密碎屑岩油气藏勘探的重点往往是寻找高效储层的发育规律，而高效储层的形成机理与成岩过程中的粘土矿物有着密切的关系，致密碎屑岩储层中常见的粘土矿物有高岭石、绿泥石、混层粘土和伊利石。通过铸体薄片、扫描电镜、背散射等研究手段，分析不同类型粘土矿物的形成机理，结合沉积相和层序地层，对其分布规律进行研究。研究结果表明，成岩粘土矿物的形成与储层碎屑颗粒的成分、气候、沉积环境及古温度等有密切关系。海（湖）平面变化对成岩阶段早期形成的粘土矿物具有明显控制作用，随后这些早期形成的粘土矿物影响着成岩晚期的粘土矿物类型、含量和分布。碎屑岩颗粒组分、沉积相和层序地层相结合，可以有效地预测碎屑岩储层中粘土矿物的形成机理和分布规律，为深层高效储层的预测提供理论基础。

Formation Mechanism and Distribution of Clay Minerals of Deeply Tight Siliciclastic Reservoirs

With the development of petroleum exploration and exploitation,the proportion of deeply buried tight siliciclastic reservoirs is increasing significantly.The key to successful exploration in tight siliciclastic reservoirs is usually to find the growing law of the efficient reservoirs.However,there is a close relationship between formation mechanism and diagenetic clayminerals.Kaolinite,chlorite,mixed-layerillite-smectite and illite are common clay minerals in tight siliciclastic reservoirs.Formation mechanism and distribution of clay minerals can be studied by thin section,SEM and BSE,with consideration of sedimentary facies and sequence stratigraphy.The results show that formation of clay minerals are influenced by framework grains composition,climate,depositional environment,temperature,and so on.Clay minerals formed in early diagenesis can be controlled by sea level changes,however,which can influence late diagenetic clay minerals.Formation mechanism and distribution of clay minerals of deeply buried tight siliciclastic reservoirs can be predicted by integrating framework grain composition,depositional setting and sequence stratigraphic study.