低渗致密气藏产能预测方法

与常规气藏相比,低渗致密气藏具有低孔、低渗、含水饱和度高等特点,其产能评价方法与常规气藏有很大不同。影响低渗气井产能的因素主要有启动压力梯度、应力敏感性和滑脱效应。文中针对低渗致密气藏的渗流特点,推导了考虑启动压力梯度、应力敏感性、滑脱效应的气井产能方程,只需对该产能方程两端求极限,即可得到其他形式的产能方程;结合具体实例,对产能测试资料进行分析,结果表明,所推导的低渗致密气藏产能方程及产能测试资料处理方法准确可靠,可广泛应用于低渗致密气藏的产能评价。

Productivity prediction methods for tight gas reservoir with low permeability

Tight gas reservoir with low permeability is eharac, terized by low porosity, low permeability and high water saturation, compared with conventional gas reservoir Evalualion method of produclivily is greatly differenl from conventional gas reservoir. Main influential factors are threshold pressure gradient, stress sensitivity and slippage effect for the productivity of low permeability gas well. Aiming at the features of tight gas reservoir with Low permeability, tbe gas well deliverability equations considering threshold pressure gradient, stress sensitivity and slippage effect are derived. Study results show thal we can gain other productivity equations through laking limits on the bolh sides of lhe productivity equation considering pressure gradient, stress sensitivity and slippage effect. Finally, we deal with lhe productivity test data. The results indicale that the deliverability equations of low permeability gas reservoir and productivity tesling data processing method are accurate and reliable and can be used tor the productivily evaluation of low permeabilily gas reservoir.