四川盆地什邡-德阳-广金地区蓬莱镇组致密气藏特征

什邡-德阳-广金区块主体位于四川盆地川西坳陷中段,构造位置位于成都凹陷北、北东部。综合地震、地质、钻井、测井、岩心、测试等资料。研究了蓬莱镇组致密气藏的来源、性质、分布特征、与沉积相的关系、成藏时间、排烃时间以及成藏特征。结果表明,研究区蓬莱镇组天然气主要来源于其下伏的须五段烃源岩,属于正常地温、异常高压环境下形成的不含硫化氢的优质干气;主成藏期大致为K2中期-E1早期,晚侏罗世-早白垩世末为主要排烃期。蓬莱镇组气藏可能是早期深部或中部气藏经构造运动改造后形成的气藏。

Tight gas reservoir characteristics of Penglaizhen Formation in Shifang-deyang-guangjin area of Sichuan Basin

Shifang-deyang-guangjin area is located in middle western Sichuan Foreland of Sichuan Basin, north and north east of Chengdu Sag. Based on sesmic, geology, drilling, logging, core and test data, discussed the origin and nature of tight gas in Penglaizhen Formation, distribution characteristics, the relationship with sedimentary facies, accumulation time, the time of hydrocarbon expulsion and accumulation characteristics. The results demonstrated that the gas of Penglaizhen Formation in studied area mainly comes from the source rock underlying fifth Xujiahe Formation, which are high quality dry gas without H2s formed in the normal temperature and abnormal high pressure environment. The main accumulation time was middle late cretaceous-early paleocence and the time of hydrocarbon expulsion was the end of late Jurassic-early cretaceous. The gas reservoir of Penglaizhen Formation may be deep in the early or middle gas reservoir by the tectonic movement after the formation of the gas reservoir.