苏里格气田东部二叠系盒8段储层次生孔隙形成主控因素

苏里格气田东部下二叠统石盒子组8段是苏里格气田东部主要含气层位,其储集空间以各类次生孔隙为主。为明确次生孔隙控制因素,结合铸体薄片鉴定与定量统计、流体包裹体温度及成分分析等手段,对研究区盒8段储层次生孔隙特征及主控因素进行了系统研究。结果表明,苏里格气田东部盒8段储层次生孔隙的形成受有机酸溶蚀、深部热流体作用共同影响;平面分布受沉积相、构造及油气运移路径复合控制。沿构造鼻隆轴线方向、基底断裂结合部位与厚砂体叠合区附近次生孔隙最发育。

Controlling factors of the secondary porosity of the hydrocarbon reservoirs from the 8th member of the Permian Shihezi Formation in eastern Sulige Gas Field, Ordos Basin

The 8th member of the Lower Permian Shihezi Formation occurs as important hydrocarbon reservoirs in eastern Sulige Gas Field,Ordos Basin. The secondary porosity and associated controlling factors of the hydrocarbon reservoirs are explored in detail on the basis of thin section examination,quantitative statistics,fluid inclusion thermometry and compositional analysis. The development of the secondary porosity in the 8th member of the Shihezi Formation is believed to be closely correlated to sedimentary microfacies distribution and organic acidic dissolution during the hydrocarbon generation and migration,and deep-seated hydrothermal fluids associated with the basement faulting. On the whole,the planar distribution of the secondary porosity is constrained by sedimentary facies,regional structures and hydrocarbon migration pathways. The secondary porosity tends to be best developed along the axial line of the nose uplift,or near the intersection of the distributary channels and the juncture of the basement faults.