低渗透油藏非达西渗流地层压力计算方法及分析

低渗透油藏非达西渗流时，地层的压力分布与常规达西流动情况下不同，储层存在压力波及不到的区域，难以有效动用。为此，基于渗流理论中质量守恒和动量守恒方程，建立了考虑启动压力梯度存在的新的不稳定渗流数学模型，推导出非达西径向流解析解和产能方程，形成了低渗透油藏新的地层压力计算方法，为低渗透储层的油藏评价和开发设计提供了理论依据。计算分析表明：低渗透油藏非达西流动下压力分布不同于以往有激励即有响应的达西流动情况，近井地带能量递减远快于常规油藏达西流动的情况，储层波及范围小，井筒外围有很大一部分面积的油藏没能有效动用。

Formation pressure calculation and analysis of low permeability reservoir with non-Darcy flow

Formation pressure distribution of non-Darcy flow in low permeability reservoir differs from Darcy flow in custom reservoir, and there are non-startup regions uncontrolled by single well. Based on mass conservation and momentum equations in theory of fluid mechanics in porous medium, the non-Darcy flow mathematic model considering threshold pressure gradient is established, which derives analytic solution of non-Darcy radial flow and deliverability equation. A new calculation method of formation pressure is presented, which provides theoretical foundation for reservoir evaluation and development design of low or ultra-low permeability reservoir. The calculation results demonstrate that there is not exciter response everywhere of non-Darcy flowing in low permeability reservoir which differs from Darcy flowing in custom reservoir. Energy decay rate of non-Darcy flowing in low permeability reservoir is faster than Darcy flowing in custom reservoir. Because of small spreading range, it exists reasonable employing radius.