特低渗、致密油藏非线性渗流数值模拟方法及其在冀东油田的应用

Numerical simulation method and its application for nonlinear flow in ultra⁃low permeability and tight oil reservoir in Jidong Oilfield

流体在致密砂岩储层多孔介质的流动过程中,流动规律表现为非线性渗流,常规基于达西渗流的油藏数值模拟方法在致密砂岩油藏中并不适用。为了更精确地表征致密砂岩储层中的流动规律,通过启动压力梯度和边界层的定量表征实验,明确了非线性渗流规律的表现形式,推导了适用于冀东油田特低渗、致密砂岩储层的非线性渗流模型,以tNavigator数值模拟软件为基础,探索形成了适合特低渗、致密砂岩油藏考虑非线性渗流规律的数值模拟方法,并在实际区块进行了应用。结果表明,非线性渗流模型模拟的累计产油量与实际累计产油量相比误差为5.47%,低于拟启动压力梯度模型的13.99%。该非线性渗流模拟方法能够使致密砂岩油藏非线性渗流规律的表征更精确,可为同类油田的开发提供参考。

Fluid flow in porous media of tight sandstone reservoir is nonlinear flow,and conventional numerical sim‑ulation method based on Darcy flow is not suitable for tight sandstone reservoir.In order to more accurately charac‑terize the flow law in tight sandstone reservoir,through quantitative characterization experiments of startup pressure gradient and boundary layer,the expression form of nonlinear flow law is determined,and a nonlinear flow model suitable for ultra-low permeability and tight sandstone reservoirs in Jidong Oilfield is deduced.Based on tNavigator numerical simulation software,a numerical simulation method suitable for ultra-low permeability and tight sand‑stone reservoirs considering nonlinear flow law is developed.The results show that the error of cumulative oil pro‑duction simulated by nonlinear flow model is 5.47%compared with actual oil production,which is lower than 13.99%of pseudo-startup pressure gradient model.The nonlinear flow simulation method proposed in this paper can get more accurate characterization of nonlinear flow law of tight sandstone reservoir,and provide reference for simi‑lar oilfield development.