The Bohai Sea Oilfield Polymer/Surfactant Binary System Optimization And Performance Research

China`s Bohai sea is area of abundant petroleum resources.China`s tertiary oil recovery technique has stepped into the state of polymer flooding,and after polymer flooding,the research and development will be focused on polymer/surfactant binary system flooding to enhance oil recovery.Therefore,in this paper,hydrophobic associated polymers and hydrolyzed polyacrylamide(HPAM)were selected as polymer,and anionic surfactant of mahogany petroleum sulfonate,nonionic surfactant(A206)and anionic-nonionic surfactant(jbs-6)were selected as surfactant.The interfacial activity and solvent property of polymer/surfactant binary system flooding under the conditions of Bohai sea oil field were investigated with interfacial tension,viscosity,micro structure,Improve recovery efficiency and so on.Polymer/surfactant binary system flooding could increase displacement efficiency through decreasing interfacial tension between oil and water.The measurement result of interfacial tension between polymer/surfactant binary system showed that nonionic surfactant and hydrolyzed polyacrylamide compound system,anionic-nonionic surfactant and hydrophobic associated polymers compound system,and anionic-nonionic and hydrolyzed polyacrylamide compound system could decrease oil-water interfacial tension better.Polymer/surfactant compound flooding could enlarge swept area by enhancing system viscosity,and the observation result of viscosity and microstructure of polymer/surfactant compound system showed that hydrolyzed polyacrylamide could not form supramolecular net structure with surfactant,and viscosity barely lost in this system.When concentration of surfactant increased,solvent viscosity of hydrophobic associated polymers and anionic-nonionic surfactant system increased gradually,and the net structure was more compact;viscosity of hydrophobic associated polymers and nonionic surfactant compound system decreased,and the net structure was sparser;viscosity of hydrophobic associated polymers and anionic surfactant system increased first and then decreased,and the net structure went compact to sparse.Among these systems,viscosity of anionic-nonionic surfactant and hydrophobic associated polymers compound system was the highest.Selected nonionic surfactant and hydrolyzed polyacrylamide compound system,anionic-nonionic surfactant and hydrophobic associated polymers compound system had the advantage of better effect of decreasing oil-water interfacial tension,higher viscosity retention,better shear resistance,better anti-aging ability and so on.The micro flooding experiment research showed that,after polymer flooding,polymer/surfactant binary system flooding could replace fragmentary oil film in the main channel and columnar crude oil in the small channel in a better way.The core flooding experiment showed that,the EOR of hydrophobic associated polymers and anionic-nonionic surfactant compound system with higher viscosity was better than that of hydrolyzed polyacrylamide and nonionic surfactant compound system.In this way,the EOR was 9% more than that of polymer flooding,in other words,polymer/surfactant binary system flooding could enhance oil recovery effiently.