Atlantic Meridional Overturning Circulation(AMOC)plays a central role in long-term climate variations through its heat and freshwater transports,which can collapse under a rapid increase of greenhouse gas forcing in c...Atlantic Meridional Overturning Circulation(AMOC)plays a central role in long-term climate variations through its heat and freshwater transports,which can collapse under a rapid increase of greenhouse gas forcing in climate models.Previous studies have suggested that the deviation of model parameters is one of the major factors in inducing inaccurate AMOC simulations.In this work,with a low-resolution earth system model,the authors try to explore whether a reasonable adjustment of the key model parameter can help to re-establish the AMOC after its collapse.Through a new optimization strategy,the extra freshwater flux(FWF)parameter is determined to be the dominant one affecting the AMOC’s variability.The traditional ensemble optimal interpolation(EnOI)data assimilation and new machine learning methods are adopted to optimize the FWF parameter in an abrupt 4×CO_(2) forcing experiment to improve the adaptability of model parameters and accelerate the recovery of AMOC.The results show that,under an abrupt 4×CO_(2) forcing in millennial simulations,the AMOC will first collapse and then re-establish by the default FWF parameter slowly.However,during the parameter adjustment process,the saltier and colder sea water over the North Atlantic region are the dominant factors in usefully improving the adaptability of the FWF parameter and accelerating the recovery of AMOC,according to their physical relationship with FWF on the interdecadal timescale.展开更多
CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility reduction.However,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fractio...CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility reduction.However,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fraction),while CO_(2) emulsion with high water cut has been rarely researched.In this paper,we carried out a comprehensive experimental study of using high water cut CO_(2)/H_(2)O emulsion for enhancing oil recovery.Firstly,a nonionic surfactant,alkyl glycosides(APG),was selected to stabilize CO_(2)/H_(2)O emulsion,and the corresponding morphology and stability were evaluated with a transparent PVT cell.Subsequently,plugging capacity and apparent viscosity of CO_(2)/H_(2)O emulsion were measured systematically by a sand pack displacement apparatus connected with a 1.95-m long capillary tube.Furthermore,a high water cut(40 vol%) CO_(2)/H_(2)O emulsion was selected for flooding experiments in a long sand pack and a core sample,and the oil recovery,the rate of oil recovery,and the pressure gradients were analyzed.The results indicated that APG had a good performance on emulsifying and stabilizing CO_(2) emulsion.An inversion from H_(2)O/CO_(2) emulsion to CO_(2)/H_(2)O emulsion with the increase in water cut was confirmed.CO_(2)/H_(2)O emulsions with lower water cuts presented higher apparent viscosity,while the optimal plugging capacity of CO_(2)/H_(2)O emulsion occurred at a certain water cut.Eventually,the displacement using CO_(2)/H_(2)O emulsion provided 18.98% and 13.36% additional oil recovery than that using pure CO_(2) in long sand pack and core tests,respectively.This work may provide guidelines for EOR using CO_(2) emulsions with high water cut.展开更多
CO_(2)emission mitigation is one of the most critical research frontiers.As a promising option of carbon capture,utilization and storage(CCUS),CO_(2)storage with enhanced gas recovery(CSEGR)can reduce CO_(2)emission b...CO_(2)emission mitigation is one of the most critical research frontiers.As a promising option of carbon capture,utilization and storage(CCUS),CO_(2)storage with enhanced gas recovery(CSEGR)can reduce CO_(2)emission by sequestrating it into gas reservoirs and simultaneously enhance natural gas production.Over the past decades,the displacement behaviour of CO_(2)—natural gas has been extensively studied and demonstrated to play a key role on both CO_(2)geologic storage and gas recovery performance.This work thoroughly and critically reviews the experimental and numerical simulation studies of CO_(2)displacing natural gas,along with both CSEGR research and demonstration projects at various scales.The physical property difference between CO_(2)and natural gas,especially density and viscosity,lays the foundation of CSEGR.Previous experiments on displacement behaviour and dispersion characteristics of CO_(2)/natural gas revealed the fundamental mixing characteristics in porous media,which is one key factor of gas recovery efficiency and warrants further study.Preliminary numerical simulations demonstrated that it is technically and economically feasible to apply CSEGR in depleted gas reservoirs.However,CO_(2)preferential flow pathways are easy to form(due to reservoir heterogeneity)and thus adversely compromise CSEGR performance.This preferential flow can be slowed down by connate or injected water.Additionally,the optimization of CO_(2)injection strategies is essential for improving gas recovery and CO_(2)storage,which needs further study.The successful K12—B pilot project provides insightful field-scale knowledge and experience,which paves a good foundation for commercial application.More experiments,simulations,research and demonstration projects are needed to facilitate the maturation of the CSEGR technology.展开更多
In this work, a novel thermal–hydraulic–mechanical (THM) coupling model is developed, where the real geological parameters of the reservoir properties are embedded. Accordingly, nine schemes of CO_(2) injection well...In this work, a novel thermal–hydraulic–mechanical (THM) coupling model is developed, where the real geological parameters of the reservoir properties are embedded. Accordingly, nine schemes of CO_(2) injection well (IW) and CH_(4) production well (PW) are established, aiming to explore the behavior of free gases after CO_(2) is injected into the depleted Wufeng–Longmaxi shale. The results indicate the free CH4 or CO2 content in the shale fractures/matrix is invariably heterogeneous. The CO_(2) involvement facilitates the ratio of free CH_(4)/CO_(2) in the matrix to that in the fractures declines and tends to be stable with time. Different combinations of IW–PWs induce a difference in the ratio of the free CH4 to the free CO_(2), in the ratio of the free CH_(4)/CO_(2) in the matrix to that in the fractures, in the content of the recovered free CH_(4), and in the content of the trapped free CO_(2). Basically, when the IW locates at the bottom Wufeng–Longmaxi shale, a farther IW–PWs distance allows more CO2 in the free phase to be trapped;furthermore, no matter where the IW is, a shorter IW–PWs distance benefits by getting more CH_(4) in the free phase recovered from the depleted Wufeng–Longmaxi shale. Hopefully, this work is helpful in gaining knowledge about the shale-based CO_(2) injection technique.展开更多
Factors affecting CO_(2) flooding of shale oil reservoir were studied by nuclear magnetic resonance(NMR) experiments, the effects of time, pressure, temperature on the recovery of CO_(2) flooding in shale oil reservoi...Factors affecting CO_(2) flooding of shale oil reservoir were studied by nuclear magnetic resonance(NMR) experiments, the effects of time, pressure, temperature on the recovery of CO_(2) flooding in shale oil reservoir were analyzed based on nuclear magnetic resonance T2 spectrum, and the effect of fracture development degree on recovery of CO_(2) flooding in shale oil reservoir was analyzed based on NMR images. In the process of CO_(2) flooding, the recovery degree of the shale oil reservoir gradually increases with time. With the rise of pressure, the recovery degree of the shale oil reservoir goes up gradually. With the rise of temperature, the recovery degree of shale oil increases first and then decreases gradually. For CO_(2) flooding in matrix core, the crude oil around the core surface is produced in the initial stage, with recovery degree going up rapidly;with the ongoing of CO_(2) injection, the CO_(2) gradually diffuses into the inside of core to produce the oil, and the increase of recovery degree slows down gradually. For CO_(2) flooding in matrix core with fractures, in the initial stage, the oil in and around the fractures are produced first, and the recovery degree goes up fast;with the extension of CO_(2) injection time, CO_(2) diffuses into the inside of the core from the fractures and the core surface to produce the oil inside the core, and the increase of recovery degree gradually slows down. Fractures increase the contact area between injected CO_(2) and crude oil, and the more the fractures and the greater the evaluation index of fractures, the greater the recovery degree of shale oil will be.展开更多
Waste selective catalytic reduction(SCR)catalysts are potential environmental hazards.In this study,the recovery of vanadium and tungsten from waste SCR catalysts by K_(2)CO_(3)roasting and water leaching was investig...Waste selective catalytic reduction(SCR)catalysts are potential environmental hazards.In this study,the recovery of vanadium and tungsten from waste SCR catalysts by K_(2)CO_(3)roasting and water leaching was investigated.The roasting and leaching conditions were optimized:the leaching efficiencies of vanadium and tungsten were 91.19%and 85.36%,respectively,when 18 equivalents of K_(2)CO_(3)were added to perform the roasting at 900℃ for 2 h,followed by leaching at 90°C for 1 h.Notably,in the described conditions,the leaching rate of silicon was only 28.55%.Titanates,including K_(2)Ti_(6)O_(13)and KTi8017,were also produced.Si removal was achieved in 85%efficiency adjusting the pH to 9.5,and the Si impurity thus isolated was composed of amorphous Si.Tungsten and vanadium were precipitated using CaCl_(2).At pH 10 and following the addition of 0.10 mol of H_(2)O_(2)and 16 equivalents of CaCl_(2),the precipitating efficiencies of tungsten and vanadium were 96.89%and 99.65%,respectively.The overall yield of tungsten and vanadium was 82.71%and 90.87%,respectively.展开更多
Based on practices of CO_(2) flooding tests in China and abroad,the recovery factor of carbon dioxide capture,utilization in displacing oil and storage(CCUS-EOR)in permanent sequestration scenario has been investigate...Based on practices of CO_(2) flooding tests in China and abroad,the recovery factor of carbon dioxide capture,utilization in displacing oil and storage(CCUS-EOR)in permanent sequestration scenario has been investigated in this work.Under the background of carbon neutrality,carbon dioxide injection into geological bodies should pursue the goal of permanent sequestration for effective carbon emission reduction.Hence,CCUS-EOR is an ultimate development method for oil reservoirs to maximize oil recovery.The limit recovery factor of CCUS-EOR development mode is put forward,the connotation differences between it and ultimate recovery factor and economically reasonable recovery factor are clarified.It is concluded that limit recovery factor is achievable with mature supporting technical base for the whole process of CCUS-EOR.Based on statistics of practical data of CO_(2) flooding projects in China and abroad such as North H79 block CO_(2) flooding pilot test at small well spacing in Jilin Oilfield etc.,the empirical relationship between the oil recovery factor of miscible CO_(2) flooding and cumulative CO_(2) volume injected is obtained by regression.Combined with the concept of oil production rate multiplier of gas flooding,a reservoir engineering method calculating CO_(2) flooding recovery factor under any miscible degree is established by derivation.It is found that when the cumulative CO_(2) volume injected is 1.5 times the hydrocarbon pore volume(HCPV),the relative deviation and the absolute difference between the recovery percentage and the limit recovery factor are less than 5%and less than 2.0 percentage points respectively.The limit recovery factor of CCUS-EOR can only be approached by large pore volume(PV)injection based on the technology of expanding swept volume.It needs to be realized from three aspects:large PV injection scheme design,enhancing miscibility degree and continuously expanding swept volume of injected CO_(2).展开更多
Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling...Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling”paths usually suffer from either low injectivity or poor gelation control.Herein,we for the first time developed an in-situ high-pressure CO_(2)-triggered gel system based on a smart surfactant,N-erucamidopropyl-N,N-dimethylamine(UC22AMPM),which was introduced into the aqueous slugs to control gas channeling inWAG processes.The water-like,low-viscosity UC22AMPM brine solution can be thickened by high-pressure CO_(2) owing to the formation of wormlike micelles(WLMs),as well as their growth and shear-induced structure buildup under shear flow.The thickening power can be further potentiated by the generation of denser WLMs resulting from either surfactant concentration augmentation or a certain range of heating,and can be impaired via pressurization above the critical pressure of CO_(2) because of its soaring solvent power.Core flooding tests using heterogeneous cores demonstrated that gas channeling was alleviated by plugging of high-capacity channels due to the in-situ gelation of UC22AMPM slugs upon their reaction with the pre-or post-injected CO_(2) slugs under shear flow,thereupon driving chase fluids into unrecovered low-permeability areas and producing an 8.0% higher oil recovery factor than the conventional WAG mode.This smart surfactant enabled high injectivity and satisfactory gelation control,attributable to low initial viscosity and the combined properties of one component and CO_(2)-triggered gelation,respectively.This work could provide a guide towards designing gels for reducing CO_(2) spillover and reinforcing the CO_(2) sequestration effect during CO_(2) enhanced oil recovery processes.展开更多
Shale oil resources have proven to be quickly producible in large quantities and have recently revolutionized the oil and gas industry.The oil content in a shale oil formation includes free oil contained in pores and ...Shale oil resources have proven to be quickly producible in large quantities and have recently revolutionized the oil and gas industry.The oil content in a shale oil formation includes free oil contained in pores and trapped oil in the organic material called kerogen.The latter can represent a significant portion of the total oil and yet pro-duction of shale oil currently targets only the free oil rather than the trapped oil in kerogen.Shale oil reservoirs also have a substantial capacity to store CO_(2)by dissolving it in kerogen.In this paper,recent progress in the research of CO_(2)-kerogen interaction and its applications in CO_(2)enhanced oil recovery and carbon sequestration in shale oil reservoirs are reviewed.The relevant topics reviewed for this relatively new area include charac-terization of organic matter,supercritical CO_(2)extraction of oil in shale,experimental and simulation study of CO_(2)-hydrocarbons counter-current diffusion in organic matter,recovery of oil in kerogen during CO_(2)huff‘n’puffprocess,and changes in microstructure of shale caused by CO_(2)-kerogen interaction.The results presented in this paper show that at reservoir conditions,supercritical CO_(2)can spontaneously replace the hydrocarbons from the organic matter of shale formations.This mass transfer process is the key to releasing organic oil saturation and maximizing the capacity of carbon storage of a shale oil reservoir.It also presents a concern of the structure change of organic materials for long term CO_(2)sequestration with shale or mudstone as the sealing rocks.展开更多
This paper presents results from a study that evaluated the potential of waste heat recovery technology within the context of commercial kitchens in Northern Ireland.The study,which involved both numerical simulation ...This paper presents results from a study that evaluated the potential of waste heat recovery technology within the context of commercial kitchens in Northern Ireland.The study,which involved both numerical simulation and measured data from five restaurant kitchens in Belfast,revealed that heat recovery technology provided substantial economic and environmental savings.Compact devices such as the spiral tube heat exchanger can be utilized as a sustainable solution to retrofit existing hot water systems.We recommend,however,that subsequent research be conducted to broaden the scope of this study by using complementary technologies such as solar panels,wind turbines,or modified cookers that would provide a holistic and sustainable solution for the catering industry.展开更多
基金supported by the National Key R&D Program of China [grant number 2023YFF0805202]the National Natural Science Foun-dation of China [grant number 42175045]the Strategic Priority Research Program of the Chinese Academy of Sciences [grant number XDB42000000]。
文摘Atlantic Meridional Overturning Circulation(AMOC)plays a central role in long-term climate variations through its heat and freshwater transports,which can collapse under a rapid increase of greenhouse gas forcing in climate models.Previous studies have suggested that the deviation of model parameters is one of the major factors in inducing inaccurate AMOC simulations.In this work,with a low-resolution earth system model,the authors try to explore whether a reasonable adjustment of the key model parameter can help to re-establish the AMOC after its collapse.Through a new optimization strategy,the extra freshwater flux(FWF)parameter is determined to be the dominant one affecting the AMOC’s variability.The traditional ensemble optimal interpolation(EnOI)data assimilation and new machine learning methods are adopted to optimize the FWF parameter in an abrupt 4×CO_(2) forcing experiment to improve the adaptability of model parameters and accelerate the recovery of AMOC.The results show that,under an abrupt 4×CO_(2) forcing in millennial simulations,the AMOC will first collapse and then re-establish by the default FWF parameter slowly.However,during the parameter adjustment process,the saltier and colder sea water over the North Atlantic region are the dominant factors in usefully improving the adaptability of the FWF parameter and accelerating the recovery of AMOC,according to their physical relationship with FWF on the interdecadal timescale.
基金The financial supports received from the National Natural Science Foundation of China(Nos.22178378,22127812)。
文摘CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility reduction.However,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fraction),while CO_(2) emulsion with high water cut has been rarely researched.In this paper,we carried out a comprehensive experimental study of using high water cut CO_(2)/H_(2)O emulsion for enhancing oil recovery.Firstly,a nonionic surfactant,alkyl glycosides(APG),was selected to stabilize CO_(2)/H_(2)O emulsion,and the corresponding morphology and stability were evaluated with a transparent PVT cell.Subsequently,plugging capacity and apparent viscosity of CO_(2)/H_(2)O emulsion were measured systematically by a sand pack displacement apparatus connected with a 1.95-m long capillary tube.Furthermore,a high water cut(40 vol%) CO_(2)/H_(2)O emulsion was selected for flooding experiments in a long sand pack and a core sample,and the oil recovery,the rate of oil recovery,and the pressure gradients were analyzed.The results indicated that APG had a good performance on emulsifying and stabilizing CO_(2) emulsion.An inversion from H_(2)O/CO_(2) emulsion to CO_(2)/H_(2)O emulsion with the increase in water cut was confirmed.CO_(2)/H_(2)O emulsions with lower water cuts presented higher apparent viscosity,while the optimal plugging capacity of CO_(2)/H_(2)O emulsion occurred at a certain water cut.Eventually,the displacement using CO_(2)/H_(2)O emulsion provided 18.98% and 13.36% additional oil recovery than that using pure CO_(2) in long sand pack and core tests,respectively.This work may provide guidelines for EOR using CO_(2) emulsions with high water cut.
基金financially supported by the National Natural Science Foundation of China(51906256 and 52074337)Fundamental Research Funds for the Central Universities(21CX06033A)
文摘CO_(2)emission mitigation is one of the most critical research frontiers.As a promising option of carbon capture,utilization and storage(CCUS),CO_(2)storage with enhanced gas recovery(CSEGR)can reduce CO_(2)emission by sequestrating it into gas reservoirs and simultaneously enhance natural gas production.Over the past decades,the displacement behaviour of CO_(2)—natural gas has been extensively studied and demonstrated to play a key role on both CO_(2)geologic storage and gas recovery performance.This work thoroughly and critically reviews the experimental and numerical simulation studies of CO_(2)displacing natural gas,along with both CSEGR research and demonstration projects at various scales.The physical property difference between CO_(2)and natural gas,especially density and viscosity,lays the foundation of CSEGR.Previous experiments on displacement behaviour and dispersion characteristics of CO_(2)/natural gas revealed the fundamental mixing characteristics in porous media,which is one key factor of gas recovery efficiency and warrants further study.Preliminary numerical simulations demonstrated that it is technically and economically feasible to apply CSEGR in depleted gas reservoirs.However,CO_(2)preferential flow pathways are easy to form(due to reservoir heterogeneity)and thus adversely compromise CSEGR performance.This preferential flow can be slowed down by connate or injected water.Additionally,the optimization of CO_(2)injection strategies is essential for improving gas recovery and CO_(2)storage,which needs further study.The successful K12—B pilot project provides insightful field-scale knowledge and experience,which paves a good foundation for commercial application.More experiments,simulations,research and demonstration projects are needed to facilitate the maturation of the CSEGR technology.
基金This study was financially supported by the National Natural Science Foundation of China(Grant Nos.51704197 and 11872258)。
文摘In this work, a novel thermal–hydraulic–mechanical (THM) coupling model is developed, where the real geological parameters of the reservoir properties are embedded. Accordingly, nine schemes of CO_(2) injection well (IW) and CH_(4) production well (PW) are established, aiming to explore the behavior of free gases after CO_(2) is injected into the depleted Wufeng–Longmaxi shale. The results indicate the free CH4 or CO2 content in the shale fractures/matrix is invariably heterogeneous. The CO_(2) involvement facilitates the ratio of free CH_(4)/CO_(2) in the matrix to that in the fractures declines and tends to be stable with time. Different combinations of IW–PWs induce a difference in the ratio of the free CH4 to the free CO_(2), in the ratio of the free CH_(4)/CO_(2) in the matrix to that in the fractures, in the content of the recovered free CH_(4), and in the content of the trapped free CO_(2). Basically, when the IW locates at the bottom Wufeng–Longmaxi shale, a farther IW–PWs distance allows more CO2 in the free phase to be trapped;furthermore, no matter where the IW is, a shorter IW–PWs distance benefits by getting more CH_(4) in the free phase recovered from the depleted Wufeng–Longmaxi shale. Hopefully, this work is helpful in gaining knowledge about the shale-based CO_(2) injection technique.
基金Basic and Forward-Looking Project of the Science and Technology Department of SINOPEC。
文摘Factors affecting CO_(2) flooding of shale oil reservoir were studied by nuclear magnetic resonance(NMR) experiments, the effects of time, pressure, temperature on the recovery of CO_(2) flooding in shale oil reservoir were analyzed based on nuclear magnetic resonance T2 spectrum, and the effect of fracture development degree on recovery of CO_(2) flooding in shale oil reservoir was analyzed based on NMR images. In the process of CO_(2) flooding, the recovery degree of the shale oil reservoir gradually increases with time. With the rise of pressure, the recovery degree of the shale oil reservoir goes up gradually. With the rise of temperature, the recovery degree of shale oil increases first and then decreases gradually. For CO_(2) flooding in matrix core, the crude oil around the core surface is produced in the initial stage, with recovery degree going up rapidly;with the ongoing of CO_(2) injection, the CO_(2) gradually diffuses into the inside of core to produce the oil, and the increase of recovery degree slows down gradually. For CO_(2) flooding in matrix core with fractures, in the initial stage, the oil in and around the fractures are produced first, and the recovery degree goes up fast;with the extension of CO_(2) injection time, CO_(2) diffuses into the inside of the core from the fractures and the core surface to produce the oil inside the core, and the increase of recovery degree gradually slows down. Fractures increase the contact area between injected CO_(2) and crude oil, and the more the fractures and the greater the evaluation index of fractures, the greater the recovery degree of shale oil will be.
基金from the Fundamental Research Funds for the Central Universities(2010YH14).
文摘Waste selective catalytic reduction(SCR)catalysts are potential environmental hazards.In this study,the recovery of vanadium and tungsten from waste SCR catalysts by K_(2)CO_(3)roasting and water leaching was investigated.The roasting and leaching conditions were optimized:the leaching efficiencies of vanadium and tungsten were 91.19%and 85.36%,respectively,when 18 equivalents of K_(2)CO_(3)were added to perform the roasting at 900℃ for 2 h,followed by leaching at 90°C for 1 h.Notably,in the described conditions,the leaching rate of silicon was only 28.55%.Titanates,including K_(2)Ti_(6)O_(13)and KTi8017,were also produced.Si removal was achieved in 85%efficiency adjusting the pH to 9.5,and the Si impurity thus isolated was composed of amorphous Si.Tungsten and vanadium were precipitated using CaCl_(2).At pH 10 and following the addition of 0.10 mol of H_(2)O_(2)and 16 equivalents of CaCl_(2),the precipitating efficiencies of tungsten and vanadium were 96.89%and 99.65%,respectively.The overall yield of tungsten and vanadium was 82.71%and 90.87%,respectively.
基金Supported by CNPC Science and Technology Project(kt2022-8-202021ZZ01).
文摘Based on practices of CO_(2) flooding tests in China and abroad,the recovery factor of carbon dioxide capture,utilization in displacing oil and storage(CCUS-EOR)in permanent sequestration scenario has been investigated in this work.Under the background of carbon neutrality,carbon dioxide injection into geological bodies should pursue the goal of permanent sequestration for effective carbon emission reduction.Hence,CCUS-EOR is an ultimate development method for oil reservoirs to maximize oil recovery.The limit recovery factor of CCUS-EOR development mode is put forward,the connotation differences between it and ultimate recovery factor and economically reasonable recovery factor are clarified.It is concluded that limit recovery factor is achievable with mature supporting technical base for the whole process of CCUS-EOR.Based on statistics of practical data of CO_(2) flooding projects in China and abroad such as North H79 block CO_(2) flooding pilot test at small well spacing in Jilin Oilfield etc.,the empirical relationship between the oil recovery factor of miscible CO_(2) flooding and cumulative CO_(2) volume injected is obtained by regression.Combined with the concept of oil production rate multiplier of gas flooding,a reservoir engineering method calculating CO_(2) flooding recovery factor under any miscible degree is established by derivation.It is found that when the cumulative CO_(2) volume injected is 1.5 times the hydrocarbon pore volume(HCPV),the relative deviation and the absolute difference between the recovery percentage and the limit recovery factor are less than 5%and less than 2.0 percentage points respectively.The limit recovery factor of CCUS-EOR can only be approached by large pore volume(PV)injection based on the technology of expanding swept volume.It needs to be realized from three aspects:large PV injection scheme design,enhancing miscibility degree and continuously expanding swept volume of injected CO_(2).
基金Financial support from the Natural Science Foundation of Sichuan Province(2022NSFSC0030)National Natural Science Foundation of China(U1762218)is gratefully acknowledged.
文摘Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling”paths usually suffer from either low injectivity or poor gelation control.Herein,we for the first time developed an in-situ high-pressure CO_(2)-triggered gel system based on a smart surfactant,N-erucamidopropyl-N,N-dimethylamine(UC22AMPM),which was introduced into the aqueous slugs to control gas channeling inWAG processes.The water-like,low-viscosity UC22AMPM brine solution can be thickened by high-pressure CO_(2) owing to the formation of wormlike micelles(WLMs),as well as their growth and shear-induced structure buildup under shear flow.The thickening power can be further potentiated by the generation of denser WLMs resulting from either surfactant concentration augmentation or a certain range of heating,and can be impaired via pressurization above the critical pressure of CO_(2) because of its soaring solvent power.Core flooding tests using heterogeneous cores demonstrated that gas channeling was alleviated by plugging of high-capacity channels due to the in-situ gelation of UC22AMPM slugs upon their reaction with the pre-or post-injected CO_(2) slugs under shear flow,thereupon driving chase fluids into unrecovered low-permeability areas and producing an 8.0% higher oil recovery factor than the conventional WAG mode.This smart surfactant enabled high injectivity and satisfactory gelation control,attributable to low initial viscosity and the combined properties of one component and CO_(2)-triggered gelation,respectively.This work could provide a guide towards designing gels for reducing CO_(2) spillover and reinforcing the CO_(2) sequestration effect during CO_(2) enhanced oil recovery processes.
基金supports by the Natural Science Foundation of China(42090024,51774310)by a Discovery Grant of Natural Sciences and Engineering Council(ESERC)of Canada.
文摘Shale oil resources have proven to be quickly producible in large quantities and have recently revolutionized the oil and gas industry.The oil content in a shale oil formation includes free oil contained in pores and trapped oil in the organic material called kerogen.The latter can represent a significant portion of the total oil and yet pro-duction of shale oil currently targets only the free oil rather than the trapped oil in kerogen.Shale oil reservoirs also have a substantial capacity to store CO_(2)by dissolving it in kerogen.In this paper,recent progress in the research of CO_(2)-kerogen interaction and its applications in CO_(2)enhanced oil recovery and carbon sequestration in shale oil reservoirs are reviewed.The relevant topics reviewed for this relatively new area include charac-terization of organic matter,supercritical CO_(2)extraction of oil in shale,experimental and simulation study of CO_(2)-hydrocarbons counter-current diffusion in organic matter,recovery of oil in kerogen during CO_(2)huff‘n’puffprocess,and changes in microstructure of shale caused by CO_(2)-kerogen interaction.The results presented in this paper show that at reservoir conditions,supercritical CO_(2)can spontaneously replace the hydrocarbons from the organic matter of shale formations.This mass transfer process is the key to releasing organic oil saturation and maximizing the capacity of carbon storage of a shale oil reservoir.It also presents a concern of the structure change of organic materials for long term CO_(2)sequestration with shale or mudstone as the sealing rocks.
文摘This paper presents results from a study that evaluated the potential of waste heat recovery technology within the context of commercial kitchens in Northern Ireland.The study,which involved both numerical simulation and measured data from five restaurant kitchens in Belfast,revealed that heat recovery technology provided substantial economic and environmental savings.Compact devices such as the spiral tube heat exchanger can be utilized as a sustainable solution to retrofit existing hot water systems.We recommend,however,that subsequent research be conducted to broaden the scope of this study by using complementary technologies such as solar panels,wind turbines,or modified cookers that would provide a holistic and sustainable solution for the catering industry.
