考虑介质变形和启动压力梯度的低渗压裂气井产能分析

低渗储层孔吼狭窄,储层物性差,基本无自然产能,需压裂才能经济开发。存在启动压力梯度并且由于有效应力改变有介质变形现象;针对低渗气藏物性特征,基于稳定渗流理论,利用保角变换原理,推导出考虑启动压力梯度和应力敏感效应以及人工压裂缝的气藏垂直井产能计算模型;分析不同应力敏感系数和启动压力梯度以及人工裂缝长度对气井产能影响。该研究对低渗气藏垂直压裂井合理产能确定有一定指导意义。

Productivity analysis of low-permeability gas reservoir wells considering threshold pressure gradient and stress sensitivity

The porosity and throat of low-permeability reservoirs is narrow and reservoir property is poor, which leads to the result that there is no natural capacity basically, fracturing to economic development exists start-up pressure gradient and due to the effective stress change is medium deformation phenomenon; In view of the low permeability gas reservoir physical characteristics. And there exists the phenomenon of pressure gradient and stress sensitivity. Based on the stable seepage theory, using the conformal mapping principle, a new calculation method for vertical gas well in low-permeability reservoir is established with the comprehensive effect of threshold pressure and stress sensitivity effect taken into consideration. And to analyze different stress sensitive coefficient and start-up pressure gradient and the artificial fracture length on vertical fractured gas well productivity. The study of vertical fracturing wells of low permeability gas reservoir has certain guiding significance to determining the rational production capacity.