五宝场含气构造沙溪庙组气藏开发潜力研究

Development Potential of Shaximiao Formation Gas Reservoir, Wubaochang Structure

五宝场沙溪庙组气藏属典型的碎屑岩低孔、低渗气藏,是川东地区第一个投入整体勘探开发的浅层河湖相砂岩气藏,开采难度极大。通过对该气藏地质特征、储集砂体展布规律及成藏模式的研究,认为五宝场沙溪庙组气藏气源来自中、下侏罗统,构造裂缝为油气主要渗滤通道,沙溪庙组曲流河三角洲前缘—三角洲平原亚相砂体为其主要储集砂体,为岩性—构造复合气藏,气井产能受构造因素影响大,气藏高产井主要分布在构造长轴方向。进而指出气藏下步挖潜方向:1上沙溪庙组产层,可在气藏构造南端向外围扩边,并提出3口建议井位及2口挖潜目标井;2下沙溪庙组产层,提出4口挖潜目标井,以加大沙溪庙组勘探开发力度,不断提高气藏整体勘探开发效益。

The Shaximiao Formation in Wubaochang structure,which is composed of clastic rock, is not only a typical low-permeability and low-porosity gas reservoir but also a shallow fluvial and lacustrine facies sandstone reservoir which was first implemented by an integrated exploration and production in eastern Sichuan Basin. And it's very difficult to carry out exploitation. After our study on its geological features, sandstone distribution laws, and reservoir- forming patterns, it is deemed that(1) its gas source comes from middle and lower Jurassic;(2) structural fractures are the main percolation channel for oil and gas;(3) meandering- river deltaic front deltaic plain subfacies sandstones are the main reservoir sandstones and this formation is a lithological-structural compound gas reservoir;(4) its deliverability is strongly affected by structural factors; and(5) in this reservoir, high-yield wells are dominantly situated at long axial of Wubaochang structure. In addition, some potential directions are pointed out, including 1 the upper Shaximiao Formation, three well sites and two potential target wells; and 2the lower Shaximiao Formation, four potential target wells. These directions to Shaximiao Formation should be further deepened, and the integrated exploration and production benefits may gradually increase.