川东五宝场地区沙溪庙组沉积相及储层物性

Sedimentary facies and reservoir physical property of Shaximiao Formation in Wubaochang Area, East Sichuan

川东五宝场区域构造形态受到以大巴山为主的北西向构造运动挤压力和来自川东北部东西向构造运动压应力的相互作用,构造轴线复合叠加、相互牵引,形态复杂多变。五宝场地区沉积岩巨厚,其间有多套生油层系,钻探证实已具备形成中型气田的资源条件。五宝场地区沙溪庙组河道沉积是最有利于储层发育的沉积相带,其主要储集空间为洞穴、孔隙、裂缝和喉道。构造作用对沙溪庙组储层有重要的影响:一方面表现在使岩石破裂而形成微裂缝,改善储集岩的储渗性能;另一方面表现在形成较大的断层,沟通了气源层和储层,成为下伏气源运移至沙溪庙组砂岩的"气源断层"通道。裂缝发育程度对沙溪庙组低孔低渗储层能否产出工业气流起着决定性作用,有"气源断层"的上覆砂体的裂缝发育有利区是勘探的首选目标。

The structural forms of Wubaochang Area are affected by the compressional force of tectonic movement from NW trend and the compressional stress of tectonic movement from WE trend mainly in Daba Mountain in northeast Sichuan, which forms the tectonic axis overlapping, inter stretch, complex diverse forms. The sedimentary rocks are very thick in Wubaochang Area, in which several oil generative assemblages exist. The area has a resource condition to be a middle-size gas field through exploration drilling. The channel deposit of Shaximiao Formation is the best sedimentary facies zone to be favour of reservoir development. The main reservoir pore spaces are cave, pore, fracture and throat. The tectonic action has a great effect on Shaximiao Formation reservoir. On the one hand, it can break the rock to make microfractures in order to improve the reservoir porosity and permeability. On the other hand, it forms great faults linking up the gas resource rocks and reservoirs. The fracture development level has a critical effect in this area. The fracture zone of overlying sandstone which has gas resource fault is favorable exploration target of principal selection.