【摘要】 为研究流体非线性渗流对疏松低渗气藏试井压力动态特征的影响,建立启动压力梯度及应力敏感效应影响下的气水两相数值试井模型,采用有限差分及IMPES方法进行求解,绘制压力及其导数双对数图版,并进行影响参数的敏感性分析。研究表明,启动压力梯度、应力敏感效应均会增加流体的渗流阻力,导致不同边界类型试井解释中压力及压力导数曲线上翘,径向流水平段消失;气水比、表皮系数对压力导数径向流段影响较小,对压力曲线的开口大小影响较大;井筒储集系数较大时会掩盖掉部分径向流特征段,但不会影响后续的径向流及边界效应阶段。该方法对存在启动压力及应力敏感效应的低渗含水气藏压力恢复试井解释具有指导意义。更多还原

【Abstract】 A gas-water two-phase numerical well test model under the influence of starting pressure gradient and stress sensitivity effect was established to study the influence of nonlinear seepage flow on the pressure dynamic characteristics in well testing of loose and low permeability gas reservoirs.Then, the model wassolved by finite difference and IMPES method. The pressure and pressure derivative plates were drawnand the sensitivity analysiss of the influencing parameters were conducted. The research results show that the starting pressure gradient and stress-sensitive effect increase the seepage resistance of the fluid, which leads to the buildup of the pressure and pressure derivative curves in the well test interpretation of different boundary types, and the disappearance of horizontal section of the radial flow. The gas-water ratio and the skin factor has little effect on the pressure derivative radio flow section, but has a great influence on the opening of the pressure curve. When the wellbore storage coefficient is large, part of radial flow section will be masked, but the subsequent radial flow and boundary effect section are not affected. The proposed method can guide the pressure buildup test interpretation of low permeability water-bearing gas reservoirs with starting pressure and stress sensitivity effects.更多还原