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针对酸压过程中形成蚓孔区和气体PVT参数随压力变化的情况,根据压后气体渗流规律变化,基于稳定渗流理论建立了考虑滑脱效应、启动压力梯度、应力敏感共同影响下低渗气藏有限导流垂直酸压裂缝井产能预测模型,并通过实例分析各因素对产能特征的影响。研究结果表明,在高流压阶段PVT参数变化对气井产能影响较小,在低流压阶段PVT参数变化对气井产能影响较大;在PVT参数变化和PVT参数不变化2种情况下,启动压力梯度、应力敏感和滑脱效应各自对气井产能的影响作用差异不大,但作用机制不同;蚓孔区系统的蚓孔长度越长,气井产能下降幅度越大,而蚓孔区渗透率越大,气井产能下降幅度越小。
In view of the change of pore pressure and gas PVT parameters with the pressure in the process of acid pressure, according to the variation of gas seepage law after pressure, the low permeability gas reservoir under considering the effect of slippage, starting pressure gradient and stress sensitivity is established based on the steady flow theory. Finite conductivity vertical fracturing fracturing well productivity prediction model, and through an example analysis of various factors on the productivity characteristics. The results show that the variation of PVT parameters has little effect on gas well productivity at high pressure stage, and the change of PVT parameters has a great influence on gas well productivity at low pressure stage. In the two cases where PVT parameters and PVT parameters are not changed, The effect of gradient, stress sensitivity and slippage effect on gas well productivity is not significant, but the mechanism of action is different. The longer the wormhole length in the wormhole zone system, the larger the decline rate of gas well productivity, and the greater the permeability in the wormhole zone, Gas well productivity decline is smaller.