川东北地区长兴组-飞仙关组碳酸盐岩台地层序充填结构及成藏效应

Sequence styles and hydrocarbon accumulation effects of carbonate rock platform in the Changxing-Feixianguan formations in the northeastern Sichuan Basin

川东北地区长兴组和飞仙关组可分别划分为两个Ⅱ型层序:PSQ1,PSQ2,TSQ1和TSQ2。除TSQ2由TST,EHST和LHST组成以外,其他层序均由TST和HST组成。在古断裂的控制下,长兴期至飞仙关期川东北碳酸盐岩台地呈现出独特的台-盆相间以及台地内的滩-洼相间沉积格局。古断裂和相对海平面变化分别通过控制沉积格局和沉积环境的水体能量变化而制约碳酸盐生产率和产出类型,从而影响碳酸盐岩层序充填结构特征。层序充填结构中发育的各成藏要素构成了川东北礁、滩气藏完整的生储盖组合。

The Changxing and Feixianguan formations in northeastern Sichuan Basin can both be divided into two type-Ⅱ sequences：PSQ1,PSQ2,TSQ1 and TSQ2.The TSQ2 sequence can be subdivided into TST,EHST and LHST,and the rest can be divided into TST and HST.Controlled by fossil fractures,during Changxing-Feixianguan period,unique sedimentary pattern of platform alternating with basin and shoal alternating with topographic low occurred in the carbonate rock platform in northeastern Sichuan Basin.The fossil fractures and relative sea-level changes influenced the productivity and type of carbonate by controlling sedimentary pattern and water energy change,and further influenced the sequence structures of carbonate rocks.Hydrocarbon pooling elements developed in the sequence structure constitute the integrated source-reservoir-caprock assemblages of reef and shoal gas reservoirs in northeastern Sichuan Basin.