考虑非达西效应的低渗气藏压裂井产能分析

相应研究表明,气体渗流特征受到启动压力梯度、滑脱效应、应力敏感等因素影响,针对这些特征,基于非达西渗流理论,应用保角变换方法并引入新的拟压力形式,推导了考虑气体上述因素共同作用下的低渗气藏无限导流垂直裂缝井产能方程。结果表明:启动压力梯度效应对低渗气藏中无限导流垂直裂缝井的产量影响较小;在高流压阶段,产量受滑脱效应和应力敏感效应影响并不明显;而在低流压阶段,随着滑脱因子增大,裂缝井产量越来越高,而随着应力敏感系数的增大,裂缝井产量越来越低。

Analysis on Fractured Well Productivity in Low-Permeability Gas Reservoirs Considering Non-Darcy Effect

A number of recent studies suggest that gas seepage characteristics may be affected by such factors as start-up pressure gradient,slippage effect and stress sensitivity.In view of the characteristics of low permeability gas reservoir,based on non-Darcy seepage theory,creating a new pseudo-pressure form,derived is an equation for calculating production capacity of vertical fracture well with infinite conductivity in low permeability gas reservoir with combined influence of start-up pressure gradient,slippage effect and stress sensitivity on low-permeability gas reservoir taken into account.Research results show that start-up pressure gradient effect has less influence on production capacity of vertical fracture well with infinite conductivity in low permeability gas reservoir,slippage effect and stress sensitivity has no obvious influence on its production capacity during high flow pressure stage,and during low flow pressure stage,fracture well will have more and more production capacity when slippage factor increases and fracture well will have less and less production capacity when stress sensitivity factor increases.