温度和有效应力对低渗储层孔渗性质的影响

Effects of temperature and stress on porosity and permeability of low permeability reservoir

探讨温度和有效应力对低渗储层渗透率和孔隙度的影响规律及内在机理,用大型岩石高温高压渗透实验仪,结合核磁共振、恒速压汞测试和相对渗透率实验进行研究.结果表明,温度不变时,岩心渗透率随有效应力的增加而递降;有效应力不变时,岩心渗透率随温度的升高而减小.核磁共振和恒速压汞测试结果表明,有效应力增加时,骨架颗粒紧密排列,岩心孔隙平均喉道和主流喉道半径减小,孔隙连通性变差,有些连通孔隙被分隔孤立,成为不可入孔隙,岩心束缚水饱和度增加.

Effects and mechanisms of temperature and stress on permeability and porosity of tow permeability reservoir were studied by large-scale high-temperature high-pressure permeability instrument, nuclear magnetic resonance testing, rate-controlled mercury penetration technique and relative permeability testing. The results show that when temperature is constant, the permeability of sandstone decreases with the increase of stress while, when stress is constant, the permeability of sandstone decreases with the increase of temperature. The results of nuclear magnetic resonance testing and rate-controlled mercury penetration experiments show that when stress increases, framework grains arranged more densely, and the average radius of pore throat and main pore throat decreases, resulting in worse connectivity, fewer accessible pores and an increase in bound water saturation.