基于启动压力梯度等效表征的低渗透油藏数值模拟

目前成熟并应用广泛的大型商业数值模拟软件均基于达西定律,但理论和实验研究均表明低渗透储层存在启动压力梯度;因此,数值模拟在低渗透油藏压裂设计、井网优化和方案研究等方面有一定局限性。部分学者研究编制的数值模拟程序无法处理百万级网格的实际油藏模型,为此,文中通过在商业数模模拟软件中巧妙地设置关键字,建立了一套启动压力梯度在油藏数值模拟中的等效表征方法。运用油藏工程方法中的极限井距理论验证了该方法的可行性;将该方法应用于BZ油田实际油藏模型,指导油田先导试验井压裂设计,证明对存在启动压力梯度的油藏方案研究具有重要意义。

Numerical simulation of low-permeability oil reservoir based on equivalent characterization of start-up pressure gradient

At present,most popular commercial numerical simulation softwares are based on the Darey's law without start-up pressure gradient.However,the start-up pressure gradient of low permeability was proved by both theory research and experiments.There are many limitations in numerical simulation for fracturing program design,well location optimization and design research for low permeability reservoir.The numerical simulation program researched by some scholars can't handle actual million-grid level reservoir model.In this paper,a new method was set up to describe start-up pressure gradient in numerical simulation by cleverly using some key words.Moreover,this method has been verified by the classical reservoir theory.The new method was applied in BZ Oilfield for pilot test well fracturing design,which shows that the start-up pressure gradient plays an important part in the reservoir project.