Due to the decline of formation pressure in the middle and late periods of low permeability reservoir development, the development effect deteriorates. Therefore, it is essential to restore and maintain reasonable formation pressure. Based on the two-phase fractional flow equation in low permeability porous media, we consider the flow characteristics in reservoirs with threshold pressure gradient and the influence of formation pressure on oil viscosity. By applying the material balance equation, we deduce the theoretical formula of future cumulative oil production with different formation pressures. In view of the contradictory relationship between cumulative oil production and water cut increasing rate, and we construct a bi-objective function to evaluate the reasonable formation pressure. Results show that during transition process from current formation pressure to reasonable formation pressure, when the reservoir formation pressure maintenance degree is 0.88, it can ensure that future cumulative oil production is relatively large and water cut increasing rate is relatively low. Under the condition of the same formation pressure maintenance degree, as threshold pressure gradient grows, the impact on cumulative oil production gradually increases. In order to provide a good development result, the formation pressure should be recovered as early as possible before it drops significantly. This method can be used to calculate reasonable formation pressure quantitatively and provide a reference for high efficiency development in low permeability reservoirs.

中文翻译：

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低渗透油藏合理地层压力维持

由于低渗透油藏开发中后期地层压力下降，开发效果恶化。因此，恢复和保持合理的地层压力至关重要。基于低渗透多孔介质中的两相分流方程，我们考虑了具有阈值压力梯度的储层中的流动特征以及地层压力对石油粘度的影响。应用物质平衡方程，推导出不同地层压力下未来累计产油量的理论公式。针对累计产油量与含水增加率之间的矛盾关系，构建双目标函数来评价合理的地层压力。结果表明，在当前地层压力向合理地层压力过渡过程中，当储层地层压力维持度为0.88时，可以保证未来累计产油量较大，含水增加率较低。在相同地层压力维持度条件下，随着临界压力梯度的增大，对累计产油量的影响逐渐增大。为取得良好的开发效果，应在地层压力明显下降前尽早恢复。该方法可用于定量计算合理地层压力，为低渗透油藏高效开发提供参考。当油藏地层压力维持度为0.88时，可以保证未来累计产油量较大，含水增加率较低。在相同地层压力维持度条件下，随着临界压力梯度的增大，对累计产油量的影响逐渐增大。为取得良好的开发效果，应在地层压力明显下降前尽早恢复。该方法可用于定量计算合理地层压力，为低渗透油藏高效开发提供参考。当油藏地层压力维持度为0.88时，可以保证未来累计产油量较大，含水增加率较低。在相同地层压力维持度条件下，随着临界压力梯度的增大，对累计产油量的影响逐渐增大。为取得良好的开发效果，应在地层压力明显下降前尽早恢复。该方法可用于定量计算合理地层压力，为低渗透油藏高效开发提供参考。在相同地层压力维持度条件下，随着临界压力梯度的增大，对累计产油量的影响逐渐增大。为取得良好的开发效果，应在地层压力明显下降前尽早恢复。该方法可用于定量计算合理地层压力，为低渗透油藏高效开发提供参考。在相同地层压力维持度条件下，随着临界压力梯度的增大，对累计产油量的影响逐渐增大。为取得良好的开发效果，应在地层压力明显下降前尽早恢复。该方法可用于定量计算合理地层压力，为低渗透油藏高效开发提供参考。