特低渗透油藏渗流特征实验研究

目前,国内外对启动压力梯度的研究基本都集中在理论研究层面,实验研究很少.用胜利油田某特低渗透油藏的天然岩心,通过实验研究了水在特低渗岩心中的启动压力梯度及流速—压差关系,束缚水饱和度下油在特低渗岩心中的启动压力梯度及流速—压差关系.通过对实验数据回归,得出了最小启动压力梯度、拟启动压力梯度、最大启动压力梯度及描述流速—压差曲线参数与岩石气测渗透率、流体黏度的经验公式,建立了确定最小、最大启动压力梯度的图版.研究表明,特低渗地层启动压力梯度及描述流速压差曲线的参数与岩石气测渗透率/流体黏度比值有很好的相关性,拟绝对渗透率与岩石气测渗透率有很好的相关性.

Experimental study on the percolation characteristic of extra low-permeability reservoir

At present,the study of threshold pressure gradient in home and abroad is only theoretical,and the experimental study is a little.The relationship between minimum threshold pressure gradient of water and the ratio of the gas log permeability of water in the extra low-permeability cores to the viscosity of it,the relationships between the velocity and the pressure gradient of water in the cores with different permeability,the relationship between minimum threshold pressure gradient of oil and the ratio of the gas log permeability of oil in the extra low-permeability cores to the viscosity of it,and the relationships between the velocity and the pressure gradient of oil in the cores with different permeability under irreducible water saturation are experimentally studied using the natural extra low-permeability cores from Shengli Oilfield.The relational formulas are obtained by the regression of the experimental data.The relational chart boards between minimum and maximum threshold pressure gradients and the ratio of the gas log permeability of oil /water in the extra low-permeability cores to the viscosity of it are presented.The study shows that all the regression relational formulas above have very good relativity,and the relationship between quasi-absolute permeability and the gas log permeability of rock has also good relativity.