摘要
选取3组岩心,在对碳酸盐岩低渗透率气藏储层岩心建立不同含水饱和度的基础上进行不同围压条件下的电阻率实验测试,分析不同围压条件下岩心电阻率及饱和度指数n随不同围压变化的关系,探讨围压对岩心电阻率的影响机理。相同围压下,低孔隙度低渗透率碳酸盐岩孔隙度越大,饱和度指数n越小。低孔隙度低渗透率碳酸盐岩在低饱和度阶段电阻率随围压的增加而减小;中含水饱和度时,随着围压的增大电阻率先减小再略微增加;在高饱和度阶段,电阻率随围压增加略微增大。随着围压的增加,饱和度指数n减小,且随围压增大,饱和度指数变化幅度降低。该研究成果为室内碳酸盐岩岩电参数获取及实践中储量精确计算提供了依据。
The saturation exponent n of Archie＇s equation is an important petro-physical parame- ter, which is usually determined by laboratory core analysis. Three groups of cores are extracted from carbonate reservoirs with lower permeability in Feixianguan and Carboniferous in Western Sichuan oilfield. Core resistivity experiments on the cores are made at different water saturations and confining pressures. With the experiments, discussed is the mechanism of confining pressure effect on the core resistivity. Regression analysis concluded： at the same pressure, the greater the porosity of the carbonate reservoir with low porosity and permeability, the smaller the water sat- uration exponent n; when the saturation is lower, the resistivity decreases as the confining pres-sure increases; when the saturation is middle, the resistivity decreases first and then increases a bit as the pressure goes up; in the higher saturation, the resistivity goes up a bit with the pres-sure increasing; as the pressures goes up, the saturation index n reduces with slower changes. The research provides a basis for acquisition of the electrical parameters from indoor carbonate experiments and accurate reservoir estimation.
出处
《测井技术》
CAS
CSCD
北大核心
2012年第5期448-450,共3页
Well Logging Technology
基金
中国石油科技创新基金研究项目(2009D50060302)
四川省科技计划项目(09ZQ026-084)
