地层压力保持水平对低渗透油藏渗透率的影响

低渗透油藏岩性致密、渗流阻力大、压力传导能力差，地层压力下降会对渗透率造成部分不可逆伤害而影响油井产能。通过室内流动试验模拟地层压力的升降过程，基于原始地层压力下的油藏渗透率，研究了不同地层压力保持水平下渗透率的保留程度；借助压汞、核磁共振、岩石力学等试验手段，对地层压力升降过程中渗透率的变化机理进行了分析。认识到地层压力下降对渗透率的伤害程度取决于岩石的初始渗透率、地层压力初次回升时机和地层压力升降次数等三个主要因素；明确了岩石的弹塑性变形是导致孔喉平均半径减小、渗透率下降的根本原因，其中塑性变形是造成渗透率不能完全恢复的主因；提出了岩石初始渗透率越低，越应及早注水保持地层压力开采的观点。 

The Impact of Formation Pressure Maintenance on Permeability in Low Permeability Reservoirs

In low permeability reservoirs,reservoir pressure decline would induce irreversible damages to formation permeability and reduce well productivity.Permeability at different reservoir pressure was studied using experimental study.Through mercury-injection test,nuclear magnetic resonance spectrometry analysis and rock mechanics test,the mechanism of permeability change in reservoir pressure fluctuation was analyzed.The degree of rock permeability reduction depends on its initial permeability,pressure rebound ...