分形油藏中无限导流垂直裂缝井的非牛顿流渗流规律

首先求得了无限大分形油藏的点源解,然后用线源积分的方法求得了单重分形油藏中无限导流垂直裂缝井非牛顿流的压力分布公式.理论分析表明,等流量解在早期和晚期与无限导流解是一致的,并求得了早期和晚期的等流量解,早期和晚期p_wD-t_D双对数曲线图上出现的直线段斜率分别为1-δ+1/α和1-δ.建立了双孔分形油藏的椭圆流数学模型,求得了其近似解,其特殊情况为单重分形油藏的椭圆流模型的结果,与等流量解对比发现,选择合适的权重,其近似效果会很好,因此椭圆流模型可用于快速试井分析.计算了窜流系数λ、弹性储量比ω、幂律指数n、参数δ变化时的无因次井底压力随时间的变化规律,从曲线形状上看与均质油藏的大致相似.分析计算结果表明,双孔分形油藏中无限导流垂直裂缝井的压力动态特征大致可分四个阶段:早期的线性流阶段;中期的裂缝介质径向流阶段;中后期质量交换压力平缓过渡阶段;晚期的平均双重介质径向流阶段.

NON-NEWTONIAN FLUIDS FLOW IN FRACTAL RESERVOIRS WITH INFINITE CONDUCTIVITY VERTICAL FRACTURED WELL

The source solution of infinite fractal reservoirs is presented to get pressure distribution of nonNewtonian flow with infinite conductivity vertical fractured wells by integral method.Analyses demonstrate the solution of uniform flux is equal to the solution of infinite conductivity fracture at early and later time,(the solution is obtained,in p_(wD)-t_D figures of early and later time yields straight line of slope 1-δ+1/α and 1-δ respectively.An elliptical flow model of dual-porosity fractal reservoirs is established to get its approximate solution.Its special case is elliptical flow model of fractal reservoirs,contrast results of the special case to the uniform flux solution and find that the approximate effect is good,if the proper parameter is chosen,the elliptical flow model can be used in fast well-test analysis.When cross flow parameter.λ storativity ratio ω,power-law parameter n,and δ is calculated,the changing law of dimensionless bottom well pressure with dimensionless time is obtained,it's similar to the results of homogeneous reservoirs in curve shape.Analysis showed that transient behavior includes four flow periods:linear flow period;fracture formation radial flow;transition flow period ;radial flow period in dual-porosity.