应力敏感低渗气藏非线性渗流特征研究

Study on the Non-linear Flow Characteristics of Low Permeability Gas Reservoir with Stress Sensitivity

低渗透气藏开发过程中,因储层压力的下降所引发的渗透率应力敏感性不可避免。为了研究应力敏感条件下低渗气藏非线性渗流特征,基于Forchheimier二项式运动方程,建立了低渗气藏产能和地层压力分布非线性渗流模型,通过实例计算分析了气井产能、地层压力和渗透率分布特征。研究结果表明:应力敏感系数越高,气井产量降低幅度越大,地层压力损失主要集中在井底附近较小的范围内;压敏效应使渗透率在井底附近损失严重,应力敏感系数越大,渗透率降低幅度越严重。研究成果对应力敏感气藏的产能预测和现场生产指导具有一定的实用价值。

During the development process of low permeability gas reservoir, it is inevitable for occurrence of stress sensitivity of permeability due to the drop in reservoir pressure. In order to study the non-linear flow characteristics in low permeability gas reservoir under stress sensitivity based on the Forchheimier binomial equation of motion, non-linear flow model for predicting the productivity and formation pressure distribution has been established. In addition, the gas well productivity, reservoir pressure and permeability distribution have been calculated through an example. The study results show that the higher the stress sensitivity coefficient, the greater the gas production decreased. The formation pressure loss occurred mainly within the small range near the bottom of the well. The permeability decreased seriously near the bottom of the well because of the stress sensitive effect. The greater the stress sensitivity coefficient, the permeability decreased more seriously. The prediction and production guidance for stress sensitivity gas reservoir. study results possess a certain practical value for productivity