特低渗油藏考虑启动压力梯度的物理模拟及数值模拟方法

从流体在低渗透多孔介质中的渗流机理出发,通过室内基础实验和基础理论研究,以及物理模拟和数值模拟方法,运用流体边界层理论,分析了由于启动压力梯度的存在而使得低渗储层产生非达西渗流的机理和规律,建立了描述低渗油气非达西渗流模型,并对特低渗长庆油田某区块一个菱形反九点注采井网进行了实例模拟计算。结果表明,启动压力梯度的存在不但降低了低渗透、特低渗透油田的开发指标,而且还增加了开采难度。增大注入率、缩小井距可以在某种程度上降低启动压力梯度的不利影响。

Physical simulation and numerical simulation of ultra-low permeability reservoir in consideration of starting pressure gradient

Based on the percolation mechanism of fluid in low permeability porous, the research of basic theory and experiment and the study of physical and numerical simulation, the mechanism and law of non-linear percolation in low-permeability porous resulted from starting pressure gradient were analyzed by using the theory of fluid boundary layer. A non-Darcy flow model of oil and gas was established. The model was used to calculate the rhomboid anti-nine point well pattern of Changqing oilfield. The simulation results indicate that the starting pressure gradient not only reduces the exploitation effect, but also enlarges the difficulty of low-permeability oilfield exploitation. Improving the ability of injection and shortening the well spaces can reduce the disadvantaged influence of the starting pressure gradient.