非线性流下低渗透气藏水平裂缝井产能研究

STUDY ON THE PRODUCTIVITY CHARACTERISTIC FOR HORIZONTAL FRACTURE WELL IN LOW-PERMEABILITY GAS RESERVOIRS WITH NON-LINEAR SEEPAGE

针对低渗气藏经压裂后形成水平裂缝,基于稳定流理论,利用等值渗流阻力法,推导建立了气井压裂后产生水平裂缝条件下,考虑非线性流影响下低渗气藏有限导流水平裂缝井产能预测模型。研究结果表明,启动压力梯度和应力敏感使气井产能下降,且启动压力梯度和应力敏感系数越大,气井产能下降幅度越大,而滑脱效应使气井产能增大,且滑脱因子越大,气井产能增加幅度越大;在高流动压力阶段,启动压力梯度对气井产能影响显著;而在低流动压力阶段,应力敏感效应对气井产能影响更大。

In view of the low permeability gas reservoir after fracturing developing horizontal fracture,based on the steady seepage theory,using the equivalent flowing resistance method, with the influence of the start-up pressure gradient,slippage effect and stress sensitivity on the low-permeability gas reservoirs taken into account,a prediction model for fracturing stimulation recovery was established for the horizontal fracture wells. The results showed that the gas well productivity decline was caused by start-up pressure gradient and stress sensitivity,and along with start-up pressure gradient and deformation coefficient of permeability enlargement,the gas well production continued to decline. While the slippage effect increased,the gas well production increased,and along with slippage factor en-largement,the gas well production continued to increase. In the high flowing pressure stage,the start-up pressure gradient had greater influence on gas well productivity,in the low flowing pressure stage,stress-sensitivity was more serious,the influ- ences of the productivity for gas well was more.