致密砂砾岩储层孔隙结构影响因素及定量评价——以玛湖凹陷玛131井区三叠系百口泉组为例

摘要

为了探索致密砂砾岩储层孔隙结构定量评价方法,并为油田的高效开发提供有效手段,以玛湖凹陷玛131井区三叠系百口泉组致密砂砾岩储层为研究对象,根据铸体薄片、扫描电镜、压汞和核磁共振等资料,分析了砂砾岩的孔隙结构及其影响因素.基于孔隙结构评价特征参数(孔喉半径均值、饱和中值压力、变异系数、排驱压力、核磁大孔比率、T2几何均值)与储层品质因子(孔隙结构定量表征参数)的统计关系,探讨砂砾岩储层孔隙结构定量评价方法,建立了常规测井曲线连续表征储层品质因子计算模型,其计算结果与实验和油井测试结果相一致,从而实现了对玛131井区百口泉组地层条件下储层品质因子的连续、定量表征.该方法和研究结果可为玛湖凹陷及其类似地区储层孔隙结构定量评价提供参考.%In order to study the quantitative evaluation method of pore structure of tight glutenite reservoir and to provide an effective method for oilfield development,the tight glutenite reservoir of Baikouquan Formation in Ma 131 well field of Mahu Sag was taken as an example,the data of cast thin sections,scanning electron microscope images,mercury injection curves and nuclear magnetic resonance (NMR) T2 spectra were used to study the pore structure and its influencing factors.Based on the statistical relationship between characteristic parameters for pore structure evaluation (average pore-throat radius,saturation median pressure,variation coefficient,displacement pressure,NMR macroporous ratio and T2 geometric mean values) and reservoir quality factors (quantitative characterization parameter of pore structure),the quantitative evaluation method of pore structure of glutenite reservoir was discussed,and then the calculation model for continuously characterizing the reservoir quality factor was established by using conventional well log data.The calculation result has a good consistence with experimental data and oil well test data.The continuous and quantitative characterization of reservoir quality factor of Baikouquan Formation in Ma 131 well field was carried out.This result could provide reference for the quantitative characterization of pore structure in Mahu Sag or other similar area.