The applications of nanotechnology in oilfields have attracted the attention of researchers to nanofluid injection as a novel approach for enhanced oil recovery. To better understand the prevailing mechanisms in such ...The applications of nanotechnology in oilfields have attracted the attention of researchers to nanofluid injection as a novel approach for enhanced oil recovery. To better understand the prevailing mechanisms in such new displacement scenarios,micromodel experiments provide powerful tools to visually observe the way that nanoparticles may mobilize the trapped oil.In this work, the e ect of silicon oxide nanoparticles on the alteration of wettability of glass micromodels was investigated in both experimental and numerical simulation approaches. The displacement experiments were performed on the original water-wet and imposed oil-wet(after aging in stearic acid/n-heptane solution) glass micromodels. The results of injection of nanofluids into the oil-saturated micromodels were then compared with those of the water injection scenarios. The flooding scenarios in the micromodels were also simulated numerically with the computational fluid dynamics(CFD) method. A good agreement between the experimental and simulation results was observed. An increase of 9% and 13% in the oil recovery was obtained by nanofluid flooding in experimental tests and CFD calculations, respectively.展开更多
Polymer solutions are used in chemical EOR processes to achieve incremental oil recoveries through obtaining favorable mobility ratios. In the process, the?in-situ?viscosity is a key parameter for the polymer flood de...Polymer solutions are used in chemical EOR processes to achieve incremental oil recoveries through obtaining favorable mobility ratios. In the process, the?in-situ?viscosity is a key parameter for the polymer flood design, as well as the changes in permeability due to the retention or adsorption (e.g.: plugging). Understanding the major causes of the plugging effects allows?predicting injectivity problems as well as optimizing project design. The objective of this work is to use glass-silicon-glass micromodels in combination with tracer particles—attached to the flooded fluids—to qualitatively and quantitatively describe the extent of permeability changes?after polymer injection. Laboratory work is performed in order to determine the physical properties of the polymer solutions when they flow through porous media, such as the presence of permeability reduction/plugging of the micromodel. A statistical analysis of the distribution and extent of plugged areas?is performed and a study of the pressure response during various injection stages will complement the study. A biopolymer (Scleroglucan) was tested and compared to a commonly used polymer, giving a direct insight into their pros and cons. Five different concentrations of polymers were tested and put into relation with their quantitative and qualitative amount of sort of called retention. The amount of adsorption was determined?experimentally in one case in order to draw the significance. By exploiting the potential of GSG-micromodels in combination with tracer particles, it was possible to visualize the reduction of flow paths and its increase during various injections for the first time. Expanding the working principle proposed in this work could provide further understanding of the behavior of any polymers.?The results obtained and workflow presented in this work allow for additional understanding of polymer solutions behavior in flooding applications. Furthermore, the definition of optimized workflows to?assess any kind of solutions in porous media and permeability changes is?supported.展开更多
CQDs-doped TiO_(2)(C-TiO_(2))has drawn increased attention in recent because of its excellent catalytic performance.Understanding the transport of C-TiO_(2)in porous media is necessary for evaluating the environmental...CQDs-doped TiO_(2)(C-TiO_(2))has drawn increased attention in recent because of its excellent catalytic performance.Understanding the transport of C-TiO_(2)in porous media is necessary for evaluating the environmental process of this new nanomaterial.Column experiments were used in this study to investigate ionic strength(IS),dissolved organic matter(DOM)and sand grain size on the transport of C-TiO_(2).The mobility of C-TiO_(2)was inhibited by the increased IS and decreased sand grain size,but was promoted by the increased DOM concentration.The promotion efficiency of DOM ranked as humic acid(HA)>alginate(Alg)>bovine serum albumin(BSA),which was in the same order as their ability to change surface charges.The micromodels of pore network were prepared via 3D printing to further reveal the deposition mechanisms and spatial/temporal distribution of C-TiO_(2)in porous space.C-TiO_(2)mainly attached to the upstream region of collectors because of interception.The collector ripening was observed after long-time deposition.The existence of DOM caused visible decrease of C-TiO_(2)deposition in the pore network.HA caused the most remarkable reduce of deposition in the three types of DOM,which was consistent with the column experiment results.This research is helpful to predict the transport of C-TiO_(2)in natural porous media.展开更多
Enhanced oil recovery （EOR） by alkaline flooding for conventional oils has been extensively studied. For heavy oils, investigations are very limited due to the unfavorable mobility ratio between the water and oil ph...Enhanced oil recovery （EOR） by alkaline flooding for conventional oils has been extensively studied. For heavy oils, investigations are very limited due to the unfavorable mobility ratio between the water and oil phases. In this study, the displacement mechanisms of alkaline flooding for heavy oil EOR are investigated by conducting flood tests in a micromodel. Two different displacement mechanisms are observed for enhancing heavy oil recovery. One is in situ water-in-oil （W/O） emulsion formation and partial wettability alteration. The W/O emulsion formed during the injection of alkaline solution plugs high permeability water channels, and pore walls are altered to become partially oil-wetted, leading to an improvement in sweep efficiency and high tertiary oil recovery. The other mechanism is the formation of an oil-in-water （O/W） emulsion. Heavy oil is dispersed into the water phase by injecting an alkaline solution containing a very dilute surfactant. The oil is then entrained in the water phase and flows out of the model with the water phase.展开更多
Increasing world request for energy has made oil extraction from reservoirs more desirable.Many novel EOR methods have been proposed and utilized for this purpose.Using nanocomposites in chemical flooding is one of th...Increasing world request for energy has made oil extraction from reservoirs more desirable.Many novel EOR methods have been proposed and utilized for this purpose.Using nanocomposites in chemical flooding is one of these novel methods.In this study,we investigated the impact of six injection solutions on the recovery of light and heavy oil with the presence of two different brines as formation water using a homogenous glass micromodel.All of the injection solutions were based on a 40,000 ppm Na Cl synthetic seawater(SSW),one of which was additive free and the others were prepared by dispersing nanocomposite silica-based polyacrylamide(NCSP),nanocomposite alumina-based polyacrylamide(NCAP),the combination of both nanocomposites silica and alumina based on polyacrylamide(NCSAP),surfactant(CTAB)and polyacrylamide(PAM)with a concentration of 1000 ppm as additives.The Stability of nanocomposites was tested against the salinity of the brine and temperature using salinity and DSC tests which were successful.Alongside stability tests,IFT,contact angle and oil recovery measurements were made.Visual results revealed that in addition to the effect of silica and alumina nanocomposite in reducing interfacial tension and wettability alteration,control of mobility ratio caused a major improvement in sweeping efficiency and oil recovery.According to the sweeping behavior of injected fluids,it was found that the main effect of surfactant was wettability alteration,for polyacrylamide was mobility control and for nanocomposites was the reduction of interfacial tension between oil and injected fluid,which was completely analyzed and checked out.Also,NCSAP with 95.83%and 70.33%and CTAB with 84.35%and 91%have the highest light oil recoveries at 250,000 ppm and 180,000 ppm salinity,respectively which is related to the superposition effect of interactions between nanocomposites,solution and oil.Based on our results it can be concluded that the most effective mechanism in oil recovery was IFT reduction which was done by CTAB reduction also by using a polymer-based nanocomposite such as NCSAP and adding the mobility control factor,the oil recovery can be further enhanced.In the case of heavy oil recovery,it can be concluded that the mobility control played a much more effective role when the PAM performed almost similarly to the CTAB and other nanocomposites with a recovery factor of around 17%.In this study,we tried to investigate the effect of different injection solutions and their related mechanisms on oil recovery.展开更多
The use of diethylenetriaminepentaacetic acid(DTPA)chelating agent has shown promising results for enhanced oil recovery(EOR)in prior research.Several mechanisms,mainly resulting from rock-fluid interaction,have been ...The use of diethylenetriaminepentaacetic acid(DTPA)chelating agent has shown promising results for enhanced oil recovery(EOR)in prior research.Several mechanisms,mainly resulting from rock-fluid interaction,have been proposed for chelating agent flooding;however,little attention has been paid to fluid-fluid interaction thus far.The assessment of these mechanisms has primarily relied on macroscopic techniques such as core flooding.This paper aims to investigate the injection of DTPA brine and its dominant mechanisms at the pore scale using a clay-coated micromodel.The micromodel tests were performed under oil-wet and water-wet states.For a more precise examination of fluid/fluid interactions,the dynamic interfacial tension(IFT)and Zeta potential were measured.It was observed that the injection of DTPA brine in water-wet state changed the saturation distribution and increased oil recovery.Based on visual inspections,this change in saturation distribution could potentially be linked to the formation of micro-dispersions and viscoelastic interfacial phenomena.Micro-dispersions facilitate flow to unswept areas,and viscoelastic interface formation reshapes the interface between oil and brine,causing disconnected oil droplets to coalesce and thus increase recovery.Under the oil-wet state,the micro-dispersion formation and wettability alteration can be the dominant mechanisms,and the amount of recovered oil was higher than that observed in the water-wet state.Furthermore,Zeta potential measurements at the interface between brine and oil showed a more negative value for DTPA brine,which is effective in wettability alteration and micro-dispersions stability.The results indicate that IFT reduction was not significant enough to be considered the dominant mechanism,although it assists in DTPA brine penetration into the crude oil and subsequent micro-dispersion formation.展开更多
Colloidal transport and deposition in porous media are complex processes that result from the interaction between hydrodynamics(velocity,pore geometry,etc.)and Derjaguin-Landau-Verwey-Overbeek(DLVO)forces(particle-par...Colloidal transport and deposition in porous media are complex processes that result from the interaction between hydrodynamics(velocity,pore geometry,etc.)and Derjaguin-Landau-Verwey-Overbeek(DLVO)forces(particle-particle and particle-surface).They have important implications for engineering applications involving the reinjection of a fluidinto a medium,such as geothermal energy.The investigation of permeability stability is critical to ensure the sustainability of activities.This work aims to study the clogging mechanisms in a rock-like porous medium using a microfluidicdevice.The pore-throat network distributions reveal that the micromodel geometry mimics real rock samples.The transport of a monodispersed suspension is studied at different concentrations.Image analysis,velocity fieldmodeling,and pressure drop measurement are used to assess preferential clogging sites and porous medium permeability reduction,respectively.Experiments have shown that retention sites are located around preferential flow paths with relatively high flow velocities.When clogged,the pore thresholds are the deposition zones that lead to a reduction in permeability.However,pore bodies may also constitute deposition zones.Interestingly,as the concentration of the suspension increases,the kinetics of the permeability reduction are delayed,and the clogging mechanisms,as well as the type of deposit,evolve.Finally,at very high concentrations,the effects of hydrodynamic stripping are more important.These observations emphasize the role of the porous medium geometry in colloidal transport and deposition and thus permeability reduction.展开更多
文摘The applications of nanotechnology in oilfields have attracted the attention of researchers to nanofluid injection as a novel approach for enhanced oil recovery. To better understand the prevailing mechanisms in such new displacement scenarios,micromodel experiments provide powerful tools to visually observe the way that nanoparticles may mobilize the trapped oil.In this work, the e ect of silicon oxide nanoparticles on the alteration of wettability of glass micromodels was investigated in both experimental and numerical simulation approaches. The displacement experiments were performed on the original water-wet and imposed oil-wet(after aging in stearic acid/n-heptane solution) glass micromodels. The results of injection of nanofluids into the oil-saturated micromodels were then compared with those of the water injection scenarios. The flooding scenarios in the micromodels were also simulated numerically with the computational fluid dynamics(CFD) method. A good agreement between the experimental and simulation results was observed. An increase of 9% and 13% in the oil recovery was obtained by nanofluid flooding in experimental tests and CFD calculations, respectively.
文摘Polymer solutions are used in chemical EOR processes to achieve incremental oil recoveries through obtaining favorable mobility ratios. In the process, the?in-situ?viscosity is a key parameter for the polymer flood design, as well as the changes in permeability due to the retention or adsorption (e.g.: plugging). Understanding the major causes of the plugging effects allows?predicting injectivity problems as well as optimizing project design. The objective of this work is to use glass-silicon-glass micromodels in combination with tracer particles—attached to the flooded fluids—to qualitatively and quantitatively describe the extent of permeability changes?after polymer injection. Laboratory work is performed in order to determine the physical properties of the polymer solutions when they flow through porous media, such as the presence of permeability reduction/plugging of the micromodel. A statistical analysis of the distribution and extent of plugged areas?is performed and a study of the pressure response during various injection stages will complement the study. A biopolymer (Scleroglucan) was tested and compared to a commonly used polymer, giving a direct insight into their pros and cons. Five different concentrations of polymers were tested and put into relation with their quantitative and qualitative amount of sort of called retention. The amount of adsorption was determined?experimentally in one case in order to draw the significance. By exploiting the potential of GSG-micromodels in combination with tracer particles, it was possible to visualize the reduction of flow paths and its increase during various injections for the first time. Expanding the working principle proposed in this work could provide further understanding of the behavior of any polymers.?The results obtained and workflow presented in this work allow for additional understanding of polymer solutions behavior in flooding applications. Furthermore, the definition of optimized workflows to?assess any kind of solutions in porous media and permeability changes is?supported.
基金This work was supported by the National Natural Science Foundation of China(No.41773110)the National Natural Science Foundation of China-Shandong Joint Fund(No.U2006214)the Shenzhen Science and Technology Research and Development Funds,China(No.JCYJ20180301171357901).
文摘CQDs-doped TiO_(2)(C-TiO_(2))has drawn increased attention in recent because of its excellent catalytic performance.Understanding the transport of C-TiO_(2)in porous media is necessary for evaluating the environmental process of this new nanomaterial.Column experiments were used in this study to investigate ionic strength(IS),dissolved organic matter(DOM)and sand grain size on the transport of C-TiO_(2).The mobility of C-TiO_(2)was inhibited by the increased IS and decreased sand grain size,but was promoted by the increased DOM concentration.The promotion efficiency of DOM ranked as humic acid(HA)>alginate(Alg)>bovine serum albumin(BSA),which was in the same order as their ability to change surface charges.The micromodels of pore network were prepared via 3D printing to further reveal the deposition mechanisms and spatial/temporal distribution of C-TiO_(2)in porous space.C-TiO_(2)mainly attached to the upstream region of collectors because of interception.The collector ripening was observed after long-time deposition.The existence of DOM caused visible decrease of C-TiO_(2)deposition in the pore network.HA caused the most remarkable reduce of deposition in the three types of DOM,which was consistent with the column experiment results.This research is helpful to predict the transport of C-TiO_(2)in natural porous media.
基金the Petroleum Technology Research Center(PTRC)in Regina,Saskatchewan,Canadathe Natural Sciences and Engineering Research Council of Canada(NSERC)for their financial support of this work
文摘Enhanced oil recovery （EOR） by alkaline flooding for conventional oils has been extensively studied. For heavy oils, investigations are very limited due to the unfavorable mobility ratio between the water and oil phases. In this study, the displacement mechanisms of alkaline flooding for heavy oil EOR are investigated by conducting flood tests in a micromodel. Two different displacement mechanisms are observed for enhancing heavy oil recovery. One is in situ water-in-oil （W/O） emulsion formation and partial wettability alteration. The W/O emulsion formed during the injection of alkaline solution plugs high permeability water channels, and pore walls are altered to become partially oil-wetted, leading to an improvement in sweep efficiency and high tertiary oil recovery. The other mechanism is the formation of an oil-in-water （O/W） emulsion. Heavy oil is dispersed into the water phase by injecting an alkaline solution containing a very dilute surfactant. The oil is then entrained in the water phase and flows out of the model with the water phase.
文摘Increasing world request for energy has made oil extraction from reservoirs more desirable.Many novel EOR methods have been proposed and utilized for this purpose.Using nanocomposites in chemical flooding is one of these novel methods.In this study,we investigated the impact of six injection solutions on the recovery of light and heavy oil with the presence of two different brines as formation water using a homogenous glass micromodel.All of the injection solutions were based on a 40,000 ppm Na Cl synthetic seawater(SSW),one of which was additive free and the others were prepared by dispersing nanocomposite silica-based polyacrylamide(NCSP),nanocomposite alumina-based polyacrylamide(NCAP),the combination of both nanocomposites silica and alumina based on polyacrylamide(NCSAP),surfactant(CTAB)and polyacrylamide(PAM)with a concentration of 1000 ppm as additives.The Stability of nanocomposites was tested against the salinity of the brine and temperature using salinity and DSC tests which were successful.Alongside stability tests,IFT,contact angle and oil recovery measurements were made.Visual results revealed that in addition to the effect of silica and alumina nanocomposite in reducing interfacial tension and wettability alteration,control of mobility ratio caused a major improvement in sweeping efficiency and oil recovery.According to the sweeping behavior of injected fluids,it was found that the main effect of surfactant was wettability alteration,for polyacrylamide was mobility control and for nanocomposites was the reduction of interfacial tension between oil and injected fluid,which was completely analyzed and checked out.Also,NCSAP with 95.83%and 70.33%and CTAB with 84.35%and 91%have the highest light oil recoveries at 250,000 ppm and 180,000 ppm salinity,respectively which is related to the superposition effect of interactions between nanocomposites,solution and oil.Based on our results it can be concluded that the most effective mechanism in oil recovery was IFT reduction which was done by CTAB reduction also by using a polymer-based nanocomposite such as NCSAP and adding the mobility control factor,the oil recovery can be further enhanced.In the case of heavy oil recovery,it can be concluded that the mobility control played a much more effective role when the PAM performed almost similarly to the CTAB and other nanocomposites with a recovery factor of around 17%.In this study,we tried to investigate the effect of different injection solutions and their related mechanisms on oil recovery.
文摘The use of diethylenetriaminepentaacetic acid(DTPA)chelating agent has shown promising results for enhanced oil recovery(EOR)in prior research.Several mechanisms,mainly resulting from rock-fluid interaction,have been proposed for chelating agent flooding;however,little attention has been paid to fluid-fluid interaction thus far.The assessment of these mechanisms has primarily relied on macroscopic techniques such as core flooding.This paper aims to investigate the injection of DTPA brine and its dominant mechanisms at the pore scale using a clay-coated micromodel.The micromodel tests were performed under oil-wet and water-wet states.For a more precise examination of fluid/fluid interactions,the dynamic interfacial tension(IFT)and Zeta potential were measured.It was observed that the injection of DTPA brine in water-wet state changed the saturation distribution and increased oil recovery.Based on visual inspections,this change in saturation distribution could potentially be linked to the formation of micro-dispersions and viscoelastic interfacial phenomena.Micro-dispersions facilitate flow to unswept areas,and viscoelastic interface formation reshapes the interface between oil and brine,causing disconnected oil droplets to coalesce and thus increase recovery.Under the oil-wet state,the micro-dispersion formation and wettability alteration can be the dominant mechanisms,and the amount of recovered oil was higher than that observed in the water-wet state.Furthermore,Zeta potential measurements at the interface between brine and oil showed a more negative value for DTPA brine,which is effective in wettability alteration and micro-dispersions stability.The results indicate that IFT reduction was not significant enough to be considered the dominant mechanism,although it assists in DTPA brine penetration into the crude oil and subsequent micro-dispersion formation.
文摘Colloidal transport and deposition in porous media are complex processes that result from the interaction between hydrodynamics(velocity,pore geometry,etc.)and Derjaguin-Landau-Verwey-Overbeek(DLVO)forces(particle-particle and particle-surface).They have important implications for engineering applications involving the reinjection of a fluidinto a medium,such as geothermal energy.The investigation of permeability stability is critical to ensure the sustainability of activities.This work aims to study the clogging mechanisms in a rock-like porous medium using a microfluidicdevice.The pore-throat network distributions reveal that the micromodel geometry mimics real rock samples.The transport of a monodispersed suspension is studied at different concentrations.Image analysis,velocity fieldmodeling,and pressure drop measurement are used to assess preferential clogging sites and porous medium permeability reduction,respectively.Experiments have shown that retention sites are located around preferential flow paths with relatively high flow velocities.When clogged,the pore thresholds are the deposition zones that lead to a reduction in permeability.However,pore bodies may also constitute deposition zones.Interestingly,as the concentration of the suspension increases,the kinetics of the permeability reduction are delayed,and the clogging mechanisms,as well as the type of deposit,evolve.Finally,at very high concentrations,the effects of hydrodynamic stripping are more important.These observations emphasize the role of the porous medium geometry in colloidal transport and deposition and thus permeability reduction.
