启动压力梯度对低渗透油藏水驱油规律的影响研究

低渗油藏存在启动压力梯度,其油水渗流规律表现为非达西渗流。本文基于经典水驱油渗流理论,通过启动压力梯度对黏度的影响关系对经典模型进行了修正,建立了考虑启动压力梯度的一维油水两相驱替数学模型,重点分析启动压力梯度对低渗透油藏见水时间规律的影响。以胜利油田渤南油田东南部五区某S砂组低渗透油藏为例进行见水时间计算,结果表明,启动压力梯度的存在会导致油井见水早,且渗透率越低,见水越早。研究成果对于低渗透油藏的合理开发具有理论指导意义。

Influence on Flow in Low Permeability Reservoir of Threshold Pressure Gradient

Due to the threshold pressure gradient, the flow in low permeability reservoir presents as non-Darcy type. Based on classic flow theory, the paper has built up a model for one-dimension and two-phase displacement by modifying the viscosity which is affected by threshold pressure gradient. Analysis is mainly focused on the influence for breakthrough time brought by threshold pressure gradient. Case study of certain S sand groups in southeastern Bonan oil field, Shengli, is conducted to calculate breakthrough time. The result shows that the threshold pressure gradient will lead to earlier breakthrough, which is also sensitive to the reservoir permeability. The result is of theoretical significance in the development of low permeability reservoirs.