考虑启动压力梯度的直井压裂渗流模型与实验

采用直井压裂技术开发低渗透稠油油藏在工程上表现出较理想的经济效益。基于渗流理论和水电模拟实验,建立了低渗透稠油油藏直井压裂后形成垂直裂缝的渗流模型。由于稠油在低渗地层中表现出非牛顿性,该公式进一步考虑了启动压力梯度、有效运动边界和有效边界压力,建立针对径向流向椭圆流转变的渐变流模型,通过半缝长与供油半径比值判断渐变流模型中的径向流、椭圆流的临界边界。设计一种存在击穿电压的溶液用于电模拟实验,适用于模拟稠油的启动压力梯度,并对启动压力梯度对产能的影响做了分析。

Influent model of vertical well fracturingSconsidering kickoff pressure gradient and laboratory experiment

Hydraulic fracturing is an important technology of stimulation in the stage. Based on percolation theory and hydropower simulation experiment, a low permeability heavy oil reservoir fracturing influent model of vertical well is established. Because heavy oil in low permeability shows non-Newtonian stratum, the formula considers kickoff pressure gradient, moving boundary and boundary pressure. The model of conversion between radial flow and elliptic flow is established. Judge the critical boundary of radial flow and elliptic flow through ratio of half fracture length and drainage radius. A breakdown voltage solution is designed for electrical simulation experiment and is applied for kickoff pressure gradient of heavy oil simulation.