油水饱和球管孔隙模型弛豫的理论计算与计算机模拟

Theoretical computation and numerical simulation of the relaxation of sphere-capillary model saturated with oil and water

根据Brownstein-Tarr理论,采用特征函数展开法,通过求解基于扩散效应的Bloch控制方程,给出了油水饱和球管孔隙模型弛豫的理论计算公式.理论计算结果表明,在水润湿条件下,油的弛豫过程只与含油饱和度有关,而与岩石的孔隙结构无关.根据理论计算结果对球管模型中水的弛豫进行了数值模拟,模拟结果显示,球和管的主弛豫过程是一个单指数函数,其余部分与之相比可以忽略,即球管模型中水的弛豫可近似为一个双指数衰减过程.

According to Brownstein-Tarr theory and using the series expansion method, the Bloch equations controlled by diffusion effect are solved for double-phase pore space of sphere-capillary model saturated with oil and water, and the theoretical relaxation computational formulas for the sphere-capillary model are obtained. The result shows that the relaxation process of oil is only related to oil saturation and isn＇ t associated with pore structure on the condition of wetness. A great deal of computation simulations were carried out based on the theoretical computational formulas, and the numerical simulation results show that the main relaxation process of sphere or capillary is a single exponential function and the other relaxation processes are negligible. In other words, the relaxation of sphere-capillary model is approximatively a double exponential descending process.