裂缝性地层流体驱替的分形模拟研究

Fractal simulation of fluid displacement in fractured reservoirs.

对裂缝地层中的流体驱替过程进行了分形模拟研究 ,用Weierstrass Mandelbrot函数构造了直线型裂缝和随机分形裂缝 ,利用改型的分形生长模型 ,计入流体的界面张力效应 ,在随机网格上模拟了裂缝地层的注水驱油过程 ,发现裂缝的维数及其宽度严重影响流体驱替前缘粘性指进的形成及演化。随着裂缝宽度的增加 ,注入流体将沿裂缝突进 ,面波及效率减小 ,沿裂缝的驱替效率随之增加。另外 ,裂缝愈复杂 ,其分形维数也愈大 ,相应的面波及效率变大 ,而沿裂缝的驱替效率减小。图 4参 6(刘振华摘 )

Fluid displacement in fractured reservoirs is studied using fractal geometry. Both straight fractures and naturally stochastic fractures are generated by random fractal method. A modified fractal growth model, in which the surface tension between driving fluid and displaced fluid is included, is used to simulated the process of water displacing oil in fractured reservoirs. The present investigation indicates that the formation and evolution of the viscous fingering in displacement front is influenced heavily by width and fractal dimension of the fracture. As the fracture width increases, areal sweep efficiency, E S, decreases and sweep efficiency along the fracture, E f, increases. In addition, the value of E S increases and E f value reduces with the growing of the fractal dimension of the fracture.