川西坳陷崇州沙溪庙组次生气藏成藏模式
Accumulation Models of Secondary Gas Reservoirs in Shaximiao Formation, Chongzhou area, Western Sichuan Depression

针对川西坳陷崇州沙溪庙组次生气藏成藏主控因素及成藏模式不清的问题，利用岩心物性、岩石薄片、储层流体包裹体测温、碳酸盐胶结物碳同位素等分析化验资料，对崇州沙溪庙组气藏成藏地质条件、成藏主控因素及成藏模式进行了研究。结果表明：崇州地区沙溪庙组构造、烃源、储层、输导等成藏地质条件有利，上沙溪庙组成藏模式属于游离相运移的先致密后成藏，天然气聚集成藏主要受砂体与烃源断层配置关系和相对优质储层发育程度控制，天然气呈邻近烃源断层聚集成藏的特征；下沙溪庙组成藏模式属于水溶相运移的边溶蚀边成藏，天然气聚集成藏主要受砂体与烃源断层配置关系和构造位置控制，天然气可远离烃源断层聚集成藏。研究成果对该区沙溪庙组下步油气勘探具有重要的指导意义。
The main controlling factors and accumulation models of secondary gas reservoirs in Shaximiao Formation of Chongzhou area are not clear. Based on the analyses of laboratory data including drill cores, rock slices, temperature measurement of fluid inclusion, carbon isotope of carbonate cement, combining with burial history and thermal evolution history analysis, the accumulation models are summarized and the main controlling factors are researched in study area. The study shows that Shaximiao Formation of Chongzhou area has superior accumulation conditions, especially in structure, hydrocarbon source, reservoir and conduction. The migration of upper Shaximiao Formation nature gas was mainly free phase, and reservoirs’ densification was earlier than its major period of accumulation. By this time, the main accumulation controlled factors were the relation between sand body and hydrocarbon fault and development of high-quality reservoir, and reservoirs were distributed in hydrocarbon fault nearby. The migration of lower Shaximiao Formation gas was water soluble phase, the accumulation model was characterized by corroding and accumulating at same time. The reservoirs were formed in the part where is far from hydrocarbon fault, and mainly influenced by the relation between sand body and hydrocarbon fault and structural location. The research results could play a key role in future oil and gas exploration of Shaximiao Formation in study area.