川西坳陷回龙构造雷口坡组天然气成藏条件

摘要

On the basis of regional petroleum geology studies,by 3D seismic interpretation and organic geochemical analysis etc.,we comprehensively analyzed the natural gas accumulation conditions in the Leikoupo Formation of the Huilong structure,Western Sichuan Depression. The study result shows that marine source rocks are well-de-veloped in the Huilong area;the hydrocarbon-source faults that vertically connect the Leikoupo Formation and un-derlying Permian marine formations and the unconformity surface at the Leikoupo Formation top in lateral direction can act as fine hydrocarbon migration and conduction systems;natural gas accumulation has fine gas source condi-tion with"two hydrocarbon supplies";the Leikoupo Formation has high-quality reservoirs and fine source-reser-voir-caprock assemblage. The Huilong structure has ideal trap type,with big fault nose trap area. Moreover,the karst fracture-cave developed region at the Leikoupo Formation top is just at the high position. The study and breakthrough in this area is of great significance for expanding exploration scope and exploration domain of the Leik-oupo Formation in the whole Western Sichuan Depression,and it is the favorable target for deploying risk prospect wells in the future.%以区域地质研究为基础,通过三维地震解释并利用有机地球化学分析等技术手段,综合分析了川西坳陷回龙构造雷口坡组天然气成藏条件及其勘探潜力.结果表明,回龙地区海相烃源岩发育,纵向上沟通雷口坡组和下伏二叠系海相层系的烃源断裂及横向上雷口坡组顶部不整合面可作为油气的良好运移疏导体系,天然气成藏具有"双源供烃"的良好气源条件,且雷口坡组优质储层发育,并具有良好的生储盖组合.回龙构造圈闭类型好、断鼻圈闭面积大,且雷口坡组顶面岩溶缝洞发育区域与高部位相叠合.该区的研究及突破对于扩大川西整个雷口坡组的勘探范围和勘探领域具有重要意义,是下一步部署风险探井的有利目标区域.