在异常高压气藏中,传统的二项式产能方程不能准确地表达气井流体渗流状况,需采用考虑气井非达西流动效应和脉动效应的三项式产能方程.当储层具有低孔低渗、非均质性强和含水饱和度高等特征时,气体渗流类似液体渗流,具有显著的“启动压力梯度效应”.因此,在三项式产能方程中添加了启动压力梯度项,并通过推导分析由启动压力梯度引起的启动压降是一个与产量相关的变量,而非常数.由此建立了考虑变启动压降的异常高压气藏新产能方程,为异常高压气藏气井合理产量的确定提供了理论依据.%In abnormal pressure gas reservoirs, traditional binomial deliverability equation is insufficient to accurately describe the fluid filtrations in a gas well, so the trinomial deliverability equation considering non-Darcy flow effect and ripple effect is needed. When the gas reservoirs are characterized by low-porosity and low-permeability, strong heterogeneity and high water saturation, the gas flow is just similar to the liquid flow and moreover featured by significant " threshold pressure gradient effect" . Therefore, a threshold pressure gradient is added to the trinomial deliverability equation, and furthermore it is derived that the threshold pressure drop caused by the pressure gradient is a variable related to the production but not a constant. Consequantly a novel deliverability equation of abnormal pressure gas reservoirs considering variable threshold pressure is established, thus the theoretical evi-dences for determining the reasonable gas production in abnormal pressure gas reservoirs are provided.
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