四川盆地西部油气地质条件优越，已发现了多个海相气藏或含气构造，是一个具备天然气勘探潜力的领域。但近20 多年来，由于勘探投入不够，海相碳酸盐岩勘探未取得大的突破，勘探程度仍然很低。文中在分别对川西坳陷西缘北、中、南3 段典型构造（气藏）剖析的基础上，初步提出了川西坳陷西缘中下三叠统油气成藏主控因素为：滩相优质储层的发育是油气成藏的基础；保存条件是油气成藏的关键。

The western Sichuan Depression has superior geologic condition of oil and gas，where has discovered many marine gas reservoir, so it is an area with gas prospecting potentia1. But in the recent twenty years, the exploration of marine carbonate reservoir did not get breakthrough, and the exploratory extent is low. The typical structural gas reservoirs in northern, middle and southern part of western margin of western Sichuan Depression are analyzed respectively. It is proposed that the development of high quality shoal facies reservoir is the basement for hydrocarbon accumulation, and the preservation condition is the key for hydrocarbon accumulation of Middle-Lower Triassic in western margin ofwestern Sichuan Depression.