红河油田长9特低渗油藏局部高孔渗优质储层特征

通过分析红河油田延长组长9段储层的岩石薄片、孔喉测试、油水相渗、启动压力梯度测试等岩心实验以及录井、测井等资料,研究了高孔渗储层特征。结果表明,高孔渗储层岩屑含量略高,云母及黏土含量低,压汞分析的孔喉结构明显优于低孔渗段,相渗曲线等渗点相对渗透率值明显高于低孔渗储层,相同含水饱和度条件下油相渗透率均较高,产水率则低10%以上;微观喉道半径大于1.2μm,启动压力梯度小于0.06 MPa/m。高孔渗储层主要成因是成岩中后期发生了较大规模的溶蚀作用,改善了长9段局部储集空间和渗流通道;高孔渗储层分布在长912储层的中下部,含油性明显要好于低孔渗段。

Characteristics of local high porosity and permeability reservoirs of Chang 9 ultra-low permeability reservoir in Honghe oilfield

Through analysis of rock thin section, pore throat test, oil-water phase permeability test, initiation pressure gradient test and other core experiments as well as well logging and borehole logging data, the characteristics of Chang 9 reservoir of Yanchang formation in Honghe oilfield was studied. The results show that the content of cuttings is slightly higher in high porosity and permeability reservoirs, and the content of mica and clay is lower. The pore-throat structure of mercury injection analysis is obviously better than that of low pore-permeability section, and the relative permeability value of the phase permeability curve is obviously higher than that of the low permeability reservoir. Under the same water saturation condition, the oil phase permeability is higher and the water yield is more than 10% lower. The micro throat radius is greater than 1.2μm and the starting pressure gradient is less than 0.06 MPa/m. The high porosity and permeability reservoirs are mainly caused by the large-scale dissolution in the middle and late diagenesis, which improves the local reservoir space and the seepage channel in Chang 9 reservoir and the reservoirs with high porosity and permeability is distributed in the middle and lower part of Chang 912 reservoir.