Abstract:

In order to solve the problem that the pressure drop curve or the pressure recovery curve made by measured data was not fitting well with the classic model curve in low permeability reservoir, on the basis of previous studies and nonlinear flow of power law model, the method of differential discrete was used to build a quick and precise method for calculating the pressure, and the calculation method of dynamic permeability and conductivity was also investigated in detail. The factor of pressure curve model was analyzed by using control variable method. The result showed that the bigger the powerlaw index was, the greater the bending upwards magnitude of the pressure curve model was; with the coefficient of the wellbore storage and skin factor becoming larger, the reservoir fluid in low permeability reservoir cost more time to flow into steady flow; for closed boundary reservoir, the pressure model curve upturns and the reservoir resolution points were very clear. The pressure curve and the pressure derivative curve intersected. For the constant pressure boundary reservoir, it was on the contrary with the closed boundary reservoir, but after the fluid flows into the quasi steady state of radial flow, model curves were a cluster of parallel inclined lines.

Key words: Low permeability reservoir, Finite difference method, Numerical simulation, Model curve, Pressure

摘要： 针对低渗透油藏中实测的压力降落或恢复曲线与经典的曲线拟合度不高的问题,基于幂律非线性渗流模式,采用差分离散方法,建立了一种快速求取压力的方法,并给出了动态渗透率和传导率的计算方法,进行了压力样板曲线敏感性分析。研究结果表明,幂律系数越大,压力样板曲线上翘幅度越大;井筒存储系数和表皮系数越大,流体进入拟稳态渗流的时间就越晚;封闭边界油藏曲线上翘的分辨点明显,并伴随曲线交叉,而定压边界则相反,但两者进入拟稳态径向渗流后,样板曲线均为一簇平行的倾斜线。

关键词: 低渗透油藏, 差分方法, 数值模拟, 样板曲线, 压力