基于低频波动采油作用下的低渗储层开发背景,对渗流孔隙介质波动控制方程进行Laplace解析–Durbin离散求解,分析低频波动采油对饱和单相一维储层渗流的影响。通过对时间t进行Laplace变换,利用迭代消去和非齐次微分方程降解解法,结合开发储层边界与初始条件,推导得到Laplace变换域内单一波作用下一维储层定压或定流量开发时的流固位移解;利用延长油田物性拟合参数,Matlab编程计算饱和水相孔隙介质和不同振动频率下饱和油相孔隙介质两类算例的渗流变化。计算结果验证了波动采油技术在储层开发过程中的增渗能力,在一定储层物性条件下存在最佳振动参数(文中最佳振动频率为10~30 Hz),使得孔隙度和渗透率增幅最大,与实验规律相符。
A pseudo threshold pressure gradient was introduced into the Biot equation to study the low-frequency vibration stimulation in low permeability reservoir. The solution of the governing equation from Laplace transform and Durbin discrete method verified that the low-frequency vibration stimulation resulted in seepage enhancement and pressure increase. Laplace transform with respect to the time,the iterative elimination and the order lowering of non-homogeneous differential equation were employed to solve the governing equation. Numerical analysis based on the expressions and fitting properties of rock from Yanchang field was carried out with the Matlab programming. Examples with the porous media saturated with water phase,or with oil phase under different vibration frequency were given to analyze the change in seepage rate,pressure,porosity,solid strain and swelling shrinking ratio of the fluid. The results showed that the seepage velocity and porosity were increased obviously in the injection side by the low-frequency vibration stimulation. There existed an optimum vibration frequency in the range of 10 to 30 Hz to reach the biggest increase in porosity and permeability,which agreed with experiment results.