川东北地区下三叠统飞仙关组碳酸盐岩储层成岩作用

Diagenesis of Carbonate Reservoir in the Lower Triassic Feixianguan Formation of the NE Sichuan Basin,China

通过薄片观察、阴极发光、扫描电镜、同位素地球化学等分析化验资料的研究,对四川盆地东北部达州—宣汉地区鸡唱剖面飞仙关组碳酸盐岩储层的岩石特征、成岩作用和成岩演化序列进行系统描述,认为该区飞仙关组飞二段鲕粒滩储层沉积相—成岩相演化与飞二段经历的2次海平面下降有关。储层的孔隙演化亦与这2次海退过程有关,孔隙大小由准沉积期的海水环境下的胶结成岩作用和混合水环境下的白云石化作用所决定。

Based on research of thin slices,cathodoluminescence,scanning electron microscope,and isotope geochemistry,we analyzed the lithologic characteristics,diagenesis and its evolution of carbonate reservoirs of the Triassic Feixianguan Formation in Jichang cliff,Dazhou-Xuanhan area.The result suggests that the evolution of depositional facies-diagenetic facies of the 2nd Member of Feixianguan Formation was related to the twice sea-level fall during the formation of the 2nd Member.The evolution of pores in the reservoirs is also related to the processes of these two regression cycles.The pore space is generated from the cementation in the sea water diagenetic environments and the dolomitization in the mixing water diagenetic environments during para-deposional periods.