To address the water sensitivity of conglomerate reservoirs,a series of core sensitivity tests were conducted to evaluate the effects of varying ionic content.These findings serve as a foundation for improving reservo...To address the water sensitivity of conglomerate reservoirs,a series of core sensitivity tests were conducted to evaluate the effects of varying ionic content.These findings serve as a foundation for improving reservoir fluid dynamics and optimizing the concentration of anti-swelling agents in water flooding operations.The experiments revealed a marked disparity in response between cores with differing permeabilities.In Core No.5,characterized by low permeability,a 0.5% anti-swelling agent achieved only a modest 7.47% reduction in water sensitivity.Conversely,in the higher-permeability Core No.8,a 5%anti-swelling agent significantly reduced the water sensitivity index by 44.84% while enhancing permeability.Further,two displacement strategies-gas flooding following water flooding and water flooding after gas injection-were tested to assess the potential of CO_(2)water-alternating-gas(WAG)displacement.CO_(2)injection after water flooding in Core No.5 increased oil recovery by 9.24%,though gas channeling,evidenced by a sharp rise in the gas-liquid ratio,emerged as a critical concern.In Core No.8,water flooding following gas injection failed to improve recovery,likely due to pronounced water sensitivity,reduced permeability,and the formation of dominant flow channels under high displacement pressure,which limited sweep efficiency.展开更多
Water alternating gas(WAG)injection is a widely used strategy for enhancing oil recovery(EOR)during gas flooding,and the mechanisms,operating parameters,and influencing factors of which have been extensively studied.H...Water alternating gas(WAG)injection is a widely used strategy for enhancing oil recovery(EOR)during gas flooding,and the mechanisms,operating parameters,and influencing factors of which have been extensively studied.However,with respect to its capacity in expanding macroscopic sweep volume under varying heterogeneities,the related results appear inadequate.In this research,three cores with different heterogeneities were used and flooded by the joint water and CO_(2) WAG,then the effects of heterogeneity on oil recovery were determined.More importantly,the cores after CO_(2) WAG injection were investigated using the nuclear magnetic resonance(NMR)technique for remaining oil distribution research,which could help us to understand the capacity of CO_(2) WAG in enlarging sweep volume at different heterogeneities.The results show that the presence of heterogeneity may largely weaken the effectiveness of water flooding,the more severe the heterogeneity,the worse the water flooding.The WAG injection of CO_(2) performs well in EOR after water flooding for all the cores with different heterogeneities;however,it could barely form a complete or full sweep throughout the low-permeability region,and un-swept bypassed regions remain.The homogeneous core is better developed by the injection of the joint water and CO_(2) WAG than the heterogeneous and fractured cases.展开更多
Residual oil zones(ROZs)have high residual oil saturation,which can be produced using CO_(2) miscible flooding.At the same time,these zones are good candidates for CO_(2) sequestration.To evaluate the coupled CO_(2)-E...Residual oil zones(ROZs)have high residual oil saturation,which can be produced using CO_(2) miscible flooding.At the same time,these zones are good candidates for CO_(2) sequestration.To evaluate the coupled CO_(2)-EOR and storage perfor-mance in ROZs for Water-Alternating-CO_(2)(WAG)flooding,a multi-compositional CO_(2) miscible model with molecular diffusion was developed.The effects of formation parameters(porosity,permeability,temperature),operation parameters(bottom hole pressure,WAG ratio,pore volume of injected water),and diffusion coeffcient on the coupled CO_(2)-EOR and storage were investigated.Five points from the CO_(2) sequestration curve and the oil recovery factor curve were selected to help better analyze coupled CO_(2)-EOR and storage.The results demonstrate that enhanced performance is observed when formation permeability is higher and a larger volume of water is injected.On the other hand,the performance diminishes with increasing porosity,molecular diffusion of gas,and the WAG ratio.When the temperature is around 100℃,coupled CO_(2)-EOR and storage performance is the worst.To achieve optimal miscible flooding,it is recommended to maintain the bottom hole pressure(BHP)of the injection well above 1.2 minimum miscibility pressure(MMP),while ensuring that the BHP of the production well remains sufficiently high.Furthermore,the tapered WAG flooding strategy proves to be profitable for enhanced oil recovery,as compared to a WAG ratio of 0.5:1,although it may not be as effective for CO_(2) sequestration.展开更多
Barry Levinson's film Wag the Dog(1997) is concerned with the technological transformation of American culture in the postmodernism which is isomorphic with the media culture of American society in the late twenti...Barry Levinson's film Wag the Dog(1997) is concerned with the technological transformation of American culture in the postmodernism which is isomorphic with the media culture of American society in the late twentieth century. By exploring three dualities illustrated in the film,this paper aims to show the insecure and uncertain categories of these oppositions under the dominant phenomena of this period: the media,so as to bring about the public's ability to discern the postmodern world as well as a new ways of thinking and living.展开更多
Gas injection is the second largest enhanced oil recovery process, next only to the thermal method used in heavy oil fields. To increase the extent of the reservoir contacted by the injected gas, the gas is generally ...Gas injection is the second largest enhanced oil recovery process, next only to the thermal method used in heavy oil fields. To increase the extent of the reservoir contacted by the injected gas, the gas is generally injected intermittently with water. This mode of injection is called water-alternating-gas (WAG). This study deals with a new immiscible water alternating gas (IWAG) EOR technique, “hot IWAG” which includes combination of thermal, solvent and sweep techniques. In the proposed method CO2 will be superheated above the reservoir temperature and instead of normal temperature water, hot water will be used. Hot CO2 and hot water will be alternatively injected into the sand packs. A laboratory test was conducted on the fractured and conventional sand packs. Slugs of water and CO2 with a low and constant rate were injected into the sand packs alternatively; slug size was 0.05 PV. Recovery from each sand pack was monitored and after that hot water and hot CO2 were injected alternatively under the same conditions and increased oil recovery from each sand pack and breakthrough were measured. Experimental results showed that the injection of hot WAG could significantly recover residual oil after WAG injection in conventional and fractured sand packs.展开更多
文摘To address the water sensitivity of conglomerate reservoirs,a series of core sensitivity tests were conducted to evaluate the effects of varying ionic content.These findings serve as a foundation for improving reservoir fluid dynamics and optimizing the concentration of anti-swelling agents in water flooding operations.The experiments revealed a marked disparity in response between cores with differing permeabilities.In Core No.5,characterized by low permeability,a 0.5% anti-swelling agent achieved only a modest 7.47% reduction in water sensitivity.Conversely,in the higher-permeability Core No.8,a 5%anti-swelling agent significantly reduced the water sensitivity index by 44.84% while enhancing permeability.Further,two displacement strategies-gas flooding following water flooding and water flooding after gas injection-were tested to assess the potential of CO_(2)water-alternating-gas(WAG)displacement.CO_(2)injection after water flooding in Core No.5 increased oil recovery by 9.24%,though gas channeling,evidenced by a sharp rise in the gas-liquid ratio,emerged as a critical concern.In Core No.8,water flooding following gas injection failed to improve recovery,likely due to pronounced water sensitivity,reduced permeability,and the formation of dominant flow channels under high displacement pressure,which limited sweep efficiency.
基金Project(KFJJ-TZ-2019-3)supported by the Open Project of Shaanxi Key Laboratory of Advanced Stimulation Technology for Oil&Gas Reservoirs,ChinaProjects(51504275,51974344)supported by the National Natural Science Foundation of China。
文摘Water alternating gas(WAG)injection is a widely used strategy for enhancing oil recovery(EOR)during gas flooding,and the mechanisms,operating parameters,and influencing factors of which have been extensively studied.However,with respect to its capacity in expanding macroscopic sweep volume under varying heterogeneities,the related results appear inadequate.In this research,three cores with different heterogeneities were used and flooded by the joint water and CO_(2) WAG,then the effects of heterogeneity on oil recovery were determined.More importantly,the cores after CO_(2) WAG injection were investigated using the nuclear magnetic resonance(NMR)technique for remaining oil distribution research,which could help us to understand the capacity of CO_(2) WAG in enlarging sweep volume at different heterogeneities.The results show that the presence of heterogeneity may largely weaken the effectiveness of water flooding,the more severe the heterogeneity,the worse the water flooding.The WAG injection of CO_(2) performs well in EOR after water flooding for all the cores with different heterogeneities;however,it could barely form a complete or full sweep throughout the low-permeability region,and un-swept bypassed regions remain.The homogeneous core is better developed by the injection of the joint water and CO_(2) WAG than the heterogeneous and fractured cases.
基金supported by the National Natural Science Foundation of China(52034010).
文摘Residual oil zones(ROZs)have high residual oil saturation,which can be produced using CO_(2) miscible flooding.At the same time,these zones are good candidates for CO_(2) sequestration.To evaluate the coupled CO_(2)-EOR and storage perfor-mance in ROZs for Water-Alternating-CO_(2)(WAG)flooding,a multi-compositional CO_(2) miscible model with molecular diffusion was developed.The effects of formation parameters(porosity,permeability,temperature),operation parameters(bottom hole pressure,WAG ratio,pore volume of injected water),and diffusion coeffcient on the coupled CO_(2)-EOR and storage were investigated.Five points from the CO_(2) sequestration curve and the oil recovery factor curve were selected to help better analyze coupled CO_(2)-EOR and storage.The results demonstrate that enhanced performance is observed when formation permeability is higher and a larger volume of water is injected.On the other hand,the performance diminishes with increasing porosity,molecular diffusion of gas,and the WAG ratio.When the temperature is around 100℃,coupled CO_(2)-EOR and storage performance is the worst.To achieve optimal miscible flooding,it is recommended to maintain the bottom hole pressure(BHP)of the injection well above 1.2 minimum miscibility pressure(MMP),while ensuring that the BHP of the production well remains sufficiently high.Furthermore,the tapered WAG flooding strategy proves to be profitable for enhanced oil recovery,as compared to a WAG ratio of 0.5:1,although it may not be as effective for CO_(2) sequestration.
文摘Barry Levinson's film Wag the Dog(1997) is concerned with the technological transformation of American culture in the postmodernism which is isomorphic with the media culture of American society in the late twentieth century. By exploring three dualities illustrated in the film,this paper aims to show the insecure and uncertain categories of these oppositions under the dominant phenomena of this period: the media,so as to bring about the public's ability to discern the postmodern world as well as a new ways of thinking and living.
文摘Gas injection is the second largest enhanced oil recovery process, next only to the thermal method used in heavy oil fields. To increase the extent of the reservoir contacted by the injected gas, the gas is generally injected intermittently with water. This mode of injection is called water-alternating-gas (WAG). This study deals with a new immiscible water alternating gas (IWAG) EOR technique, “hot IWAG” which includes combination of thermal, solvent and sweep techniques. In the proposed method CO2 will be superheated above the reservoir temperature and instead of normal temperature water, hot water will be used. Hot CO2 and hot water will be alternatively injected into the sand packs. A laboratory test was conducted on the fractured and conventional sand packs. Slugs of water and CO2 with a low and constant rate were injected into the sand packs alternatively; slug size was 0.05 PV. Recovery from each sand pack was monitored and after that hot water and hot CO2 were injected alternatively under the same conditions and increased oil recovery from each sand pack and breakthrough were measured. Experimental results showed that the injection of hot WAG could significantly recover residual oil after WAG injection in conventional and fractured sand packs.
