Study Of Enhanced Oil Recovery Technology In Tertiary-main Layers

The partial block of the major reservoirs in Xingbei Development Zone in Daqing has startedsubsequent water flooding of polymer flooding, and the strong-base ASP flooding has begunindustrial application, but the Tertiary-main Layer in which64.5%of region’s geological reservesis still flooding by water, and the composite water-cut has reached more than91.3%. Ifdepending on the water flooding, it is of great difficulty to improve the recovery, and it’s noteconomical. The field tests of polymer flooding for Tertiary-main Layers has carried out inDaqing Oilfield, and the results show that the enhanced recovery is about5%. The field tests ofsurfactant/ploymer(SP) flooding for the main oil layers have been carried out in Shengli Oilfieldand the enhanced recovery is about10%. The field tests of alkali/surfactant/ploymer (ASP)flooding for the main oil layers have been carried out in Daqing Oilfield and the enhancedrecovery is above20%. It indicates that the enhanced recovery is improved by using the floodingsystem of SP/ASP in main oil layers. Therefore, it is necessary to carry out EOR of SP/ASP inthe Tertiary-main Layers of Xingbei Development Zone. The adaptability of SP/ASP with theTertiary-main Layers is evaluated by the laboratory experiment. It provide technology supportfor the exploitation of the Tertiary-main Layers.The adaptability of the strong base ASP, weak base ASP and SP with the Tertiary-mainLayers is evaluated in this work paper. Through studying by the laboratory experiments, theenhanced recovery of the flooding system is investigated. The results show that: the capability ofHLX surfactant SP, ZC-surfactant SP and the strong base ASP to reduce the interfacial tension issatisfactory, but the weak base ASP system can not achieve the ultra-low interfacial tension inthe scope of the evaluation. The stability of the interfacial tension of the strong base ASP isbetter than that of SP, and The stability of the interfacial tension of HLX surfactant SP is better toZC-surfactant SP. When the injection scheme is designed as0.3PV ASP or SP slug plus0.2PVpolymer slug, the strong base ASP can achieve the best enhancing oil recovery result. The strongbase ASP system can enhance oil recovery by19.11%with a NaOH concentration of1.2wt%and0.3wt%of Alkyl benzene sulfonate surfactant. But the weak base ASP has the lowest enhancingrecovery value of13.28%over water flooding; Incremental recovery value of HLX surfactant SPis higher than that of ZC-2surfactant SP and the former can enhance oil recovery by15.31%after water flooding.