英西下干柴沟组上段碳酸盐岩油藏成藏过程及分布规律

Accumulation and Distribution of Carbonate Rock Reservoirs in Upper Section of Lower Ganchaigou Member in Yingxi Area

为了明确柴达木盆地英西下干柴沟组上段(E_(3)^(2))碳酸盐岩油藏成藏过程及分布规律,开展了岩心描述、分析化验、储层特征分析、构造分析等研究。研究认为:英西下干柴沟组上段(E_(3)^(2))为一套半深湖相碳酸盐岩沉积,具有明显混积特征;储层储集空间为广泛发育的晶间孔,以及构造作用产生的裂缝及角砾间孔;油气的持续充注、盐岩盖层的封盖以及储层致密导致该套储层广泛含油,晚喜山构造运动使该套地层“由凹变隆”,并形成了复杂裂缝系统,同时导致油气重新调整和汇聚,形成了现今油藏的“广覆分布、局部甜点”特征。

In order to make clear about accumulation and distribution features of carbonate rock reservoirs in the upper section of lower Ganchaigou Member(E_(3)^(2))in Yingxi area of Tsaidam Basin,the study is made from the aspects of core description,analysis and tests,and construction analysis.Study shows that a set of deep-water fine-grained carbonate deposits has developed in E_(3)^(2)in Yingxi area with'obvious mixed characteristics.Reservoir space includes widespread intergranular pore,fracture and breccia pore generated by tectonism.Continuous oil and gas filling,salt caprock and tight reservoir lead to extensive oil-bearing of the reservoirs.The Late Himalayan tectonic movement resulted in the formation"from depression to uplift",and formed a large number of fracture systems.At the same time,it led to the readjustment and convergence of oil and gas,which laid a foundation for high oil and gas production and led to the characteristic of"wide-ranging distribution with local dessert"in hydrocarbon reservoirs.