川西坳陷须三-须四段含油气系统生排烃过程与主要成藏期关系

Relation between the main accumulation stage and the process of generation and expulsion of hydrocarbon in T_3 x^3-T_3 x^4 petroleum system of Upper Triassic in the west Sichuan depression,China

川西坳陷不同地区须三-须四段含油气系统主要成藏期各不相同。作者以烃源岩演化过程中各阶段的最大古地温和最大埋深为基础,结合实钻资料,确立了川西坳陷须三-须四段含油气系统不同地区烃源岩的生排烃阶段,并利用不同生排烃阶段生排烃量、砂泥岩孔隙度变化和油气成藏之间的关系,确定了不同地区的主要成藏期,同时进行了对比研究。东西方向上,在中部地区该含油气系统的主要成藏期都为晚侏罗世;而在南北方向上,北部地区明显要早于中部和南部地区。

Based on the maximum paleogeotemperature and buried depth of each stage in the source rock evolution process and combined the real data of drilled wells, the paper establishes the hydrocarbon generating and expulsion- stages of source rocks in the T3x^3- T3x^4 petroleum system of different areas in the west Sichuan depression. Using the relation among quantity of different hydrocarbon-generating and expulsion stage and the porosity variation of sandstone and mudstone and oil/gas accumulation, the paper establishes the main accumulation stages in different areas, and at the same time, makes a comparative study. The main accumulation stages were all in Late Jurassic in this petroleum system in the middle part in latitudinal direction, but that of north area was earlier than that of the middle and south areas in meridional direction.