Experimental Research Of Polymer And Surfactant Displacement In Daqing Third Type Reserviors

In this paper, in order to explore adaptability of the betaine polymer-surfactant system in daqing third type reservoirs. In berea core and daqing third type reservoirs natural oil sands filling tube models, The Jing No. 2 betaine system evaluation research,different formulations of betaine polymer-surfactant system optimization research,daqing third type reservoirs betaine polymer-surfactant system experimental research are carried out.Jing No. 2 betaine system increase betaine content a little, the interfacial tension reduce is not obvious. After joining polymer aid, interfacial tension and viscosity increase significantly. After adding alkali, interfacial tension and viscosity reduce significantly. Jing No. 2 betaine surfactant has viscosity increasing effect, with the increase of polymer concentration, interfacial tension is increased. In same viscosity conditions just joining alkali, interfacial tension reduces unapparent. Comparing improve oil recovery effect and economic benefit, injection of 0.3 PV of betaine polymer-surfactant system(0.3%) + 0.2 PV protection slug is the best solution.In condition of berea cores and viscosity is similar, the mere pursuit of ultra-low interfacial tension does not make better effect on improving oil recovery. Consider lowering interfacial tension and emulsification at the same time, which makes a relatively good effect to improve oil recovery, lower interfacial tension and stronger emulsification can greatly improve the recovery ratio. In berea cores, Liu mixture3 betaine polymer-surfactant system improves recovery ratio is best and whose injectivity is best.In condition of 20 cm third type reservoirs sand filling tube and viscosity is similar, ultra-low interfacial tension has not obvious effect to improve the recovery ratio. Because the alkali in asp system interaction between mineral in oil sands consumes large amounts of alkali, betaine polymer-surfactant system and alkalescent sulphonate asp system effect almost unanimously to improve recovery ratio. Liu mixture1 and Liu mixture2 betaine polymer-surfactant system has good injectivity, alkalescent sulphonate asp system has poor injectivity. This is due to alkali interacts with mineral in oil sands forming precipitation, which damages layer, leading to poor injectivity. In 50 cm sand filling tube, due to adsorption in the sand filling tube, oil displacement efficiency is lower than 20 cm sand filling tube. Betaine polymer-surfactant system is suitable for daqing third type reservoirs, which is the feasible choice to enhance oil recovery in daqing third type reservoirs.