In the process of water-flooding development of heavy oil reservoir,due to the high viscosity and oil-water mobility ratio of heavy oil,there are some problems such as poor fluidity,high residual oil saturation and lo...In the process of water-flooding development of heavy oil reservoir,due to the high viscosity and oil-water mobility ratio of heavy oil,there are some problems such as poor fluidity,high residual oil saturation and low recovery efficiency,which seriously restrict the efficient development of heavy oil.The molecular structure characteristics of asphaltenes and resins in heavy oil were analyzed.Based on the three most concerned properties of chemical agents,including the emulsification performance,the interface performance and the oil washing performance,three chemical oil displacement agents for heavy oil reservoirs were developed,and the structure of the chemical agents were characterized by high resolution mass spectrometry.The performance evaluation of chemical agents and core displacement experiments show that there is no obvious correlation between the properties of chemical agents,including interfacial tension,emulsifying ability and oil washing ability.For heavy oil reservoirs,the emulsification and viscosity reduction performance of chemical agents was more important than the oil washing capacity,and the oil washing capacity was more important than the interface performance.Viscosity reduction performance was the key parameter of oil displacement agent suitable for heavy oil reservoir.The composite binary system consisting of the viscosity reducer and the polymer had better oil recovery than using viscosity reducer alone.展开更多
To reduce the viscosity of highly-viscous oil of the Tahe oilfield （Xinjiang,China）,an oilsoluble polybasic copolymer viscosity reducer for heavy oil was synthesized using the orthogonal method.The optimum reaction ...To reduce the viscosity of highly-viscous oil of the Tahe oilfield （Xinjiang,China）,an oilsoluble polybasic copolymer viscosity reducer for heavy oil was synthesized using the orthogonal method.The optimum reaction conditions are obtained as follows：under the protection of nitrogen,a reaction time of 9 h,monomer mole ratio of reaction materials of 3：2：2 （The monomers are 2-propenoic acid,docosyl ester,maleic anhydride and styrene,respectively）,initiator amount of 0.8% （mass percent of the sum of all the monomers） and reaction temperature of 80 oC.This synthesized viscosity reducer is more effective than commercial viscosity reducers.The rate of viscosity reduction reached 95.5% at 50 oC.Infrared spectra （IR） and interfacial tensions of heavy oil with and without viscosity reducer were investigated to understand the viscosity reduction mechanism.When viscosity reducer is added,the molecules of the viscosity reducer are inserted amongst the molecules of crude oil,altering the original intermolecular structure of crude oil and weakening its ability to form hydrogen bonds with hydroxyl or carboxyl groups,so the viscosity of crude oil is reduced.Field tests of the newly developed oil-soluble viscosity reducer was carried out in the Tahe Oilfield,and the results showed that 44.5% less light oil was needed to dilute the heavy oil to achieve the needed viscosity.展开更多
基金supported by the 13th Five-Year Plan National Key Project of China (NO.2016ZX0511-003-004 and No.2017ZX05049-003-008)
文摘In the process of water-flooding development of heavy oil reservoir,due to the high viscosity and oil-water mobility ratio of heavy oil,there are some problems such as poor fluidity,high residual oil saturation and low recovery efficiency,which seriously restrict the efficient development of heavy oil.The molecular structure characteristics of asphaltenes and resins in heavy oil were analyzed.Based on the three most concerned properties of chemical agents,including the emulsification performance,the interface performance and the oil washing performance,three chemical oil displacement agents for heavy oil reservoirs were developed,and the structure of the chemical agents were characterized by high resolution mass spectrometry.The performance evaluation of chemical agents and core displacement experiments show that there is no obvious correlation between the properties of chemical agents,including interfacial tension,emulsifying ability and oil washing ability.For heavy oil reservoirs,the emulsification and viscosity reduction performance of chemical agents was more important than the oil washing capacity,and the oil washing capacity was more important than the interface performance.Viscosity reduction performance was the key parameter of oil displacement agent suitable for heavy oil reservoir.The composite binary system consisting of the viscosity reducer and the polymer had better oil recovery than using viscosity reducer alone.
文摘To reduce the viscosity of highly-viscous oil of the Tahe oilfield （Xinjiang,China）,an oilsoluble polybasic copolymer viscosity reducer for heavy oil was synthesized using the orthogonal method.The optimum reaction conditions are obtained as follows：under the protection of nitrogen,a reaction time of 9 h,monomer mole ratio of reaction materials of 3：2：2 （The monomers are 2-propenoic acid,docosyl ester,maleic anhydride and styrene,respectively）,initiator amount of 0.8% （mass percent of the sum of all the monomers） and reaction temperature of 80 oC.This synthesized viscosity reducer is more effective than commercial viscosity reducers.The rate of viscosity reduction reached 95.5% at 50 oC.Infrared spectra （IR） and interfacial tensions of heavy oil with and without viscosity reducer were investigated to understand the viscosity reduction mechanism.When viscosity reducer is added,the molecules of the viscosity reducer are inserted amongst the molecules of crude oil,altering the original intermolecular structure of crude oil and weakening its ability to form hydrogen bonds with hydroxyl or carboxyl groups,so the viscosity of crude oil is reduced.Field tests of the newly developed oil-soluble viscosity reducer was carried out in the Tahe Oilfield,and the results showed that 44.5% less light oil was needed to dilute the heavy oil to achieve the needed viscosity.
