低渗透储层可动剩余油核磁共振分析

摘要

针对有代表性密闭取芯岩芯平行样，分别进行油水饱和度和油水高速离心驱替实验核磁共振分析，定量获得储层目前剩余油饱和度、采出油相对量、可动油饱和度及驱油效率上限等参数，对比各参数建立储层可动剩余油饱和度核磁共振分析方法。研究表明，建立岩芯饱和油束缚水状态和水驱油的最佳离心力分别为2.250 MPa和0.220 MPa，4个渗透率级别（≥50、[10，50）、[1，10）和<1 mD）储层采出油饱和度分别为23.49%、16.81%、8.70%和9.99%，可动油饱和度分别为50.34%、43.76%、29.67%和22.89%，可动剩余油饱和度分别为26.85%、26.95%、20.97%和12.90%，由于储层非均质性影响，大于10 mD储层采出油明显高于10 mD以下储层，但大于10 mD储层可动油饱和度较高，故可动剩余油饱和度也较高，小于1 mD的储层可动剩余油明显低于其他储层。%This study analyzes oil-water saturation of reservoir and high-speed centrifugal oil-water displacement experiment by NMR respectively aiming at representative Parallel cores form sealed coring,and establishes NMR method for reservoir movable remaining oil saturation analysis through quantitatively comparing parameters,which include reservoir remaining oil saturation at present,relative quantity of produced oil,movable oil saturation and upper efficiency of oil displacement. The research shows that the best centrifugal forces to set up saturated oil bound water state and to drive oil are 2.250 MPa and 0.220 MPa respectively. For four permeability level(≥50、[10,50)、[1,10)and<1 mD)reservoir,produced oil saturation are 23.49%,16.81%,8.70%and 9.99%respectively;movable oil saturation are 50.34%,43.76%,29.67%and 22.89%respec-tively,and movable remaining oil saturation are 26.85%,26.95%,20.97%and 12.90%respectively. Produced oil saturation of reservoir above 10 mD is higher than that of reservoir less 10 mD,which is obviously due to reservoir heterogeneity,but movable remaining oil saturation of reservoir greater than 10 mD is higher because of its higher movable oil saturation. Movable remaining oil saturation of reservoir less than 1 mD is lower than that of other reservoirs evidently.