四川盆地川西坳陷中段构造演化对中三叠统雷口坡组油气成藏的控制作用

The structural evolution of the middle section of the West Sichuan Depression in the Sichuan Basin controlled the hydrocarbon accumulation in the Middle Triassic Leikoupo Formation

孟宪武 刘勇 石国山 陈兰 朱兰 蔡左花

MENG Xianwu LIU Yong SHI Guoshan CHEN Lan ZHU Lan CAI Zuohua

中国石化 西南油气分公司 勘探开发研究院, 成都 610041

Exploration and Development Research Institute, SINOPEC Southwest Branch Company, Chengdu, Sichuan 610041, China

中三叠统雷口坡组在四川盆地川西坳陷中段的金马—鸭子河构造提交探明储量千亿立方米，新场、马井地区同样也获得了工业气流并提交控制、预测储量，但区内构造演化过程及油气成藏配置关系还不明确。通过对周缘露头、盆地内钻井样品的镜质体反射率、扫描电镜及流体包裹体等分析，并结合构造解释，明确了川西坳陷中段的局部构造最早形成于印支早期，对雷口坡组油气成藏起关键作用的构造演化时期为早—中侏罗世；通源断层或“接力式”断层输导系统可作为良好的天然气运移通道，有利于油气富集成藏；局部古构造高点以及储层、输导系统等关键成藏要素配置关系良好且后期构造形变破坏弱的地区为最有利勘探区。

The Middle Triassic Leikoupo Formation of Jinma-Yazihe structure in the middle section of Western Sichuan Depression has submitted over 100 billion cubic meters of proved natural gas reserves. An industrial gas flow has also been obtained in Xinchang and Majing area, and the controlled and predicted reserves have been submitted. However, the relationship between structural evolution process and hydrocarbon accumulation configuration is still unclear. Through the analysis of vitrinite reflectance, scanning electron microscopic observation, analysis of fluid inclusion of peripheral outcrop and drilling samples, and combined with structural interpretation, the following results have been indicated. It is clear that the local structure in the middle section of Western Sichuan Depression was formed in the early Indosinian, and the Early-Middle Jurassic was a critical tectonic evolution period for hydrocarbon accumulation in the Leikoupo Formation. Meanwhile, the faults connected to sources or "contact" fault migration system provided pathways for natural gas migration, which was conducive for hydrocarbon enrichment. The local paleo-structural high points with a good configuration of key accumulation factors such as reservoirs and transport systems and weak structural deformation are the most favorable exploration area.

中国石化“十条龙”重大科技攻关项目 P16092

https://doi.org/10.11781/sysydz202106986