一种测定低渗油藏启动压力的新方法

A new method of measuring starting pressure for low permeability reservoir

低渗油藏孔隙细小,渗流不符合达西定律,流体在其中流动存在启动压力。根据低渗油藏渗流特点,设计了合理确定启动压力的测试方法。利用胜利油田天然低渗岩心、产出水及现场脱气原油配制的模拟油,测定了单相水及束缚水饱和度下油的启动压力及非线性渗流规律,回归得到了启动压力梯度与岩石气测渗透率和流体粘度比值的关系。结果表明,利用该测试方法能准确地测定低渗及特低渗岩心的启动压力;油、水的启动压力梯度与岩石气测渗透率和粘度的比值呈幂指数关系,且随渗透率与粘度比值的降低而迅速增加。

Because the pore and throat of low permeability reservoir are very small, so the fluid flow doesn＇t conform to Darcy law, and there is starting pressure for fluid flow. According to the characteristics of fluid flow in low permeability reservoir, a new experimental method of measuring starting pressure was designed. Using the natural low permeability reservoir rocks and formation water and oil from Shengli Oilfield, the starting pressure and non-linear flow laws of water and oil at irreducible water saturation were investigated. And the relationship of starting pressure and the ratio of gas permeability and fluid viscosi- ty was regressed. The results show that the starting pressure of low and ultra-low permeability reservoirs can be determined by this experimental methgd. The relationship of starting pressure and the ratio ol（ gas permeability and fluid viscosity can be described by power exponential function, and the starting pressure of water or oil at irreducible water saturation increases with the ratio of gas permeability and fluid viscosity decreasing.