川西南复杂构造区震旦系-寒武系油气保存条件

Preservation conditions of Sinian-Cambrian oil and gas in complex structural area of Southwest Sichuan

通过对川西南地区构造形态、断裂特征、地层出露情况及盖层条件等进行综合分析,结合油气显示、压力系数、地层水矿化度及水型等生产动态,开展油气保存条件研究;在此基础上,以油气成藏理论为指导,建立川西南地区油气保存条件评价体系,进行等级划分。结果表明,川西南震旦系-寒武系油气保存条件较差的地区多分布在盆缘-盆外的构造变形强烈区或深大断裂发育区,且大面积出露下古生界地层,保存条件受到不同程度的破坏;而盆内受构造运动作用影响小,且断裂发育程度低、断距小、切穿层位较少、油气保存条件好,有利于油气成藏富集。

Through comprehensive analysis of structural morphology and fault characteristics,formation exposure and caprock conditions in Southwest Sichuan,combined with the hydrocarbon show,pressure coefficient,formation water salinity and water type,the research on preservation conditions has been carried out.On this basis,guided by the accumulation theory,the evaluation system of preservation conditions in Southwest Sichuan is established and classified.The results show that the areas Sinian-Cambrian system with poor preservation conditions are mostly distributed in the areas with strong structural deformation or deep-large faults outside the basin edge.Besides that,exposed in a large area,the preservation conditions of the lower Paleozoic strata are damaged in different degrees.While less affected by tectonic movement,the basin inside has low fault development degree,small fault distance,less cutting horizon and good preservation conditions,which is favorable for hydrocarbon accumulation.