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除启动压力梯度外致密气藏还存在应力敏感,在实验确定应力敏感参数的基础上,引入虚拟裂缝概念,利用保角变换方法,考虑应力敏感和启动压力梯度建立了气藏水平井产能方程,同时分析了应力敏感、启动压力梯度、水平井长度等对产能的影响。结果表明:产能方程与试采产能的误差小于7%,验证了产能方程的可靠性;应力敏感和启动压力梯度均使产能降低,其中应力敏感占主要作用;应力敏感在低井底流压时对产能影响严重,启动压力梯度在高井底流压时对产能影响较大;水平井长度是影响产能的主控因素。该研究丰富了致密气藏水平井产能计算方法,并为水平井长度和生产压差的优化提供了理论指导。
In addition to starting the pressure gradient, the tight gas reservoirs are still stress-sensitive. Based on the experimentally determined stress-sensitive parameters, the concept of virtual fracture is introduced. By using the conformal mapping method and stress sensitivity and starting pressure gradient, At the same time, the effects of stress sensitivity, starting pressure gradient and horizontal well length on productivity were also analyzed. The results show that the error of capacity equation and trial production capacity is less than 7%, which verifies the reliability of productivity equation. Both stress sensitivity and starting pressure gradient reduce productivity, of which stress sensitivity plays a major role. The production capacity has a serious impact. The start-up pressure gradient has a great influence on the productivity when the high-bottom-hole pressure is applied. The length of the horizontal well is the main factor affecting the production capacity. The study enriches the calculation method of horizontal well productivity in tight gas reservoirs and provides theoretical guidance for the optimization of horizontal well length and production pressure difference.