王府断陷火二段火山岩储层孔隙结构评价

Pore structure evaluation of volcanic reservoir of the 2nd Member of Huoshiling Formation in Wangfu fault depression

为更好地评价王府断陷火二段火山岩储层的孔隙结构特征,笔者基于核磁测井T_2谱和岩芯压汞实验,采用非线性刻度法划分储层类型,分段构建了各储层的伪毛管压力曲线,并计算了平均孔隙半径、中值压力等参数,进一步评价了储层的孔隙结构特征。结果表明,对Ⅰ类和Ⅱ类储层中的大孔隙(> 33 ms)采用对数刻度方法,小孔隙(<33 ms)采用幂指数刻度方法,对Ⅲ类储层采用幂指数刻度方法,使得T_2谱转换的伪毛细管压力曲线与实测毛细管压力曲线吻合得非常好。孔隙半径大、中值压力小的伪毛管压力曲线对应的孔隙结构较好,为研究区有利储层。

In order to preferably evaluate the pore structure characteristics of the 2 nd Member of Huoshiling Formation in Wangfu fault depression,the pseudo capillary pressure curve of each reservoir is constructed using nonlinear calibration method to classify the reservoir types based on the T2 spectrum of nuclear magnetic resonance logging and core mercury injection experiment. The average pore radius,median pressure and other parameters are calculated to further evaluate the pore structure characteristics of the reservoir. The results show that when logarithmic calibration method is used for large pores( > 33 ms) in type Ⅰ and type Ⅱ reservoirs,power index calibration method is used for small pores( < 33 ms),and power index calibration method is used for class III reservoirs,the pseudo capillary pressure curve converted from T2 spectrum is in good agreement with the measured capillary pressure curve. The pseudo capillary pressure curve with large pore radius and small median pressure has better pore structure,which is a favorable reservoir in the study area.