Modeling reservoir permeability is one of the crucial tasks in reservoir simulation studies.Traditionally,it is done by kriging-based methods.More rigorous modeling of the permeability results in more reliable outputs...Modeling reservoir permeability is one of the crucial tasks in reservoir simulation studies.Traditionally,it is done by kriging-based methods.More rigorous modeling of the permeability results in more reliable outputs of the reservoir models.Recently,a new category of geostatistical methods has been used for this purpose,namely multiple point statistics(MPS).By this new category of permeability modeling methods,one is able to predict the heterogeneity of the reservoir permeability as a continuous variable.These methods consider the direction of property variation in addition to the distances of known locations of the property.In this study,the reservoir performance of a modified version of the SPE 10 solution project as a pioneer case is used for investigating the efficiency of these methods and paralleling them with the kriging-based one.In this way,the permeability texture concept is introduced by applying some MPS methods.This study is accomplished in the conditions of real reservoir dimensions and velocities for the whole reservoir life.A continuous training image is used as the input of calculation for the permeability modeling.The results show that the detailed permeability of the reservoir as a continuous variable makes the reservoir simulation show the same fluid front movement and flooding behavior of the reservoir similar to the reference case with the same permeability heterogeneity.Some MPS methods enable the reservoir simulation to reproduce the fluid flow complexities such as bypassing and oil trapping during water flooding similar to the reference case.Accordingly,total oil production is predicted with higher accuracy and lower uncertainty.All studied cases are identical except for the permeability texture.Even histograms and variograms of permeabilities for the studied reservoir are quite similar,but the performance of the reservoir shows that kriging-based method results have slightly less accuracy than some MPS methods.Meanwhile,it results in lower uncertainty in outputs for this water flooding case performance.展开更多
Several direct or indirect approaches have been proposed to measure diffusion coefficient of gases into liquids.The main complexity of indirect techniques such as pressure decay method is interpreting early pressure-t...Several direct or indirect approaches have been proposed to measure diffusion coefficient of gases into liquids.The main complexity of indirect techniques such as pressure decay method is interpreting early pressure-time data which strongly affected by incubation period effect or convective instability.In the current approach,accurate apparatus and precise experimental setup including a high pressure and temperature PVT cell,a high precision Sanchez pump,heating and recording sub-system are implemented and a novel data analysis procedure is applied to modify pressure decay method.The effect of incubation period is reduced remarkably and diffusion coefficient of carbon dioxide in water in wide range of pressures and temperatures is determined and the effects of temperature,pressure and carbon dioxide phase alteration from gas to supercritical are investigated and the value of uncertainty is estimated.Furthermore,diffusion coefficient of CO_(2) and methane in an oil sample from one of the Iranian southwest oil formations is determined precisely using the experimental approach while no incubation period is detected.The results showed that incubation period duration decreases with increasing diffusion coefficient.Additionally,when CO_(2) state is gas,rate of increasing diffusion coefficient with pressure is decreased with temperature and when CO_(2) state is supercritical,the rate of increasing diffusion coefficient with pressure is decreased significantly.展开更多
Sandstone reservoirs often contain clay particles that can cause damage and reduce permeability during low-salinity water flooding.In this study,the effect of surfactants on fine migration in clay-rich sandstones and ...Sandstone reservoirs often contain clay particles that can cause damage and reduce permeability during low-salinity water flooding.In this study,the effect of surfactants on fine migration in clay-rich sandstones and its impact on oil recovery was investigated.First,the impact of surfactants on interparticle forces in fine-matrix,fine-fine,and oil-matrix systems was modeled.The results showed that both CTAB(cetyltrimethyl ammonium bromide)and QS(quillaja saponin)cause EDL compaction,weakening the repulsive forces.However,SDS(sodium dodecyl sulfate)and TX(triton X-100)do not affect the EDL.Next,the effect of surfactants on IFT reduction and wettability alteration was experimentally investigated.All surfactants reduced IFT due to the surface excessive concentration mechanism.The wettability alteration experiment illustrated that although QS and CTAB compact EDL around oil and matrix particles leading to attraction force augmentation,they both alter wettability through adsorption on matrix and carboxylic groups present in crude oil,respectively.Surfactant aqueous solutions were then injected into various clay-rich sandstone sanpacks,which resulted in increased oil recovery.However,the mechanisms leading to enhanced oil recovery variedby surfactant type.CTAB increased recovery by 10%through IFT reduction and wettability alteration,while SDS and TX increased recovery by 12%and 9%,respectively,through wettability alteration and extreme fine migration.In contrast,partial fine migration in the QS flooding experiment reached a recovery increase of 18%.Permeability trends through experiments were also recorded.During CTAB injection,permeability did not reduce,while QS aqueous solution reduced rock permeability to 5 m D.SDS and TX reduced the magnitude of permeability to 2 m D.In conclusion,this study demonstrates that surfactants can effectively improve oil recovery in clay-rich sandstones by altering the interparticle forces,reducing IFT,and changing wettability.The results suggest that the type of surfactant used should be carefully selected to achieve the desired recovery increase without affecting the permeability of the reservoir.展开更多
Floods and earthquakes are the most common natural disasters,causing significant damage and casualties in urban communities.Although academic research has focused on assessing cities'ability to withstand these nat...Floods and earthquakes are the most common natural disasters,causing significant damage and casualties in urban communities.Although academic research has focused on assessing cities'ability to withstand these natural disasters,there is a lack of established frameworks for evaluating resilience against multiple hazards.This research integrates the earthquake and flood resilience indicators to create a comprehensive resilience assess-ment framework.This study integrated seismic and flood resilience indicators and categorized them into 27 clusters.It also used the DEMATEL(Decision-Making Trial and Evaluation Laboratory)method to determine the significance of clusters and prioritize them.This research identified 13 cause clusters and 14 effect clusters of indicators for seismic and flood resilience.The‘response capacity'cluster has the most impact on seismic and flood resilience,while the‘transportation and accessibility'cluster is the most affected cluster.This article presents a framework for evaluating flood and seismic resilience and makes suggestions for future research.展开更多
A vertical slot fishway(VSF)is among the most effective and commonly used fishway structures to enable fish to pass through artificial barriers such as dams and weirs in the river.Nevertheless,such structures need fur...A vertical slot fishway(VSF)is among the most effective and commonly used fishway structures to enable fish to pass through artificial barriers such as dams and weirs in the river.Nevertheless,such structures need further improvements in providing better swimming conditions for fish inside the pool and enhancing attraction at the entrance.Therefore,the main objective of this study was to investigate the influence of slope and whether integrating some cylinder structures inside the fishway could enhance further attraction and provide better swimming conditions for fish.This study consists of several numerical simulations,first considering the fishway without cylinder elements while testing three different slopes under two different discharges.Then,the same numerical simulations were conducted,considering cylinder elements of different diameters and arrangements inside the fishway.The numerical model was validated by comparing computed velocities with those measured experimentally from the literature.The results show that the maximum velocity and turbulent kinetic energy(TKE)in the main jet increase as the discharge increases on the same slope.The flow velocity and TKE decrease in the areas inside the pool and between the two baffles.Introducing cylinder elements inside the fishway reduces the principal flow’s maximum velocity.Also,inside the pool,low-velocity regions were expanding.A comparison between the design with a cylinder and the simple VSF indicates that the presence of a cylinder reduced the maximum velocities for the smallest and highest slopes by 6.21%and 9.86%on average,respectively.However,in terms of TKE,cylinders inside the fishway could provide better performance than simple VSF,mainly for low-flow conditions.Finally,this study’s solution-oriented findings provide insights that could help design cost-effective fishways by improving particularly fish attraction to the fishway.展开更多
This study reports the applicability of quillaja saponin(QS)as a vigorous and environmentally friendly shale swelling inhibitor.QS is a natural surfactant,which is extracted from herbal sources.The inhibition strength...This study reports the applicability of quillaja saponin(QS)as a vigorous and environmentally friendly shale swelling inhibitor.QS is a natural surfactant,which is extracted from herbal sources.The inhibition strength of this surfactant was assessed through various experiments,such as sedimentation,inhibition,filtration,particle size,Scanning Electron Microscope(SEM)images,and cutting recovery.Data obtained from these tests illustrated that QS greatly inhibits clays from swelling.The optimal concentration for QS in this intend was 10 g/L.Compatibility of this surfactant with other common additives was also investigated,which showed that it is totally compatible.Finally,the potential inhibition mechanism was assessed through thermal gravimetric analysis(TGA),zeta potential,and contact angle measurement experiments.Surface coating,and wettability alteration of clay particles to the oil-wet state was recognized as the most probable mechanism.展开更多
文摘Modeling reservoir permeability is one of the crucial tasks in reservoir simulation studies.Traditionally,it is done by kriging-based methods.More rigorous modeling of the permeability results in more reliable outputs of the reservoir models.Recently,a new category of geostatistical methods has been used for this purpose,namely multiple point statistics(MPS).By this new category of permeability modeling methods,one is able to predict the heterogeneity of the reservoir permeability as a continuous variable.These methods consider the direction of property variation in addition to the distances of known locations of the property.In this study,the reservoir performance of a modified version of the SPE 10 solution project as a pioneer case is used for investigating the efficiency of these methods and paralleling them with the kriging-based one.In this way,the permeability texture concept is introduced by applying some MPS methods.This study is accomplished in the conditions of real reservoir dimensions and velocities for the whole reservoir life.A continuous training image is used as the input of calculation for the permeability modeling.The results show that the detailed permeability of the reservoir as a continuous variable makes the reservoir simulation show the same fluid front movement and flooding behavior of the reservoir similar to the reference case with the same permeability heterogeneity.Some MPS methods enable the reservoir simulation to reproduce the fluid flow complexities such as bypassing and oil trapping during water flooding similar to the reference case.Accordingly,total oil production is predicted with higher accuracy and lower uncertainty.All studied cases are identical except for the permeability texture.Even histograms and variograms of permeabilities for the studied reservoir are quite similar,but the performance of the reservoir shows that kriging-based method results have slightly less accuracy than some MPS methods.Meanwhile,it results in lower uncertainty in outputs for this water flooding case performance.
文摘Several direct or indirect approaches have been proposed to measure diffusion coefficient of gases into liquids.The main complexity of indirect techniques such as pressure decay method is interpreting early pressure-time data which strongly affected by incubation period effect or convective instability.In the current approach,accurate apparatus and precise experimental setup including a high pressure and temperature PVT cell,a high precision Sanchez pump,heating and recording sub-system are implemented and a novel data analysis procedure is applied to modify pressure decay method.The effect of incubation period is reduced remarkably and diffusion coefficient of carbon dioxide in water in wide range of pressures and temperatures is determined and the effects of temperature,pressure and carbon dioxide phase alteration from gas to supercritical are investigated and the value of uncertainty is estimated.Furthermore,diffusion coefficient of CO_(2) and methane in an oil sample from one of the Iranian southwest oil formations is determined precisely using the experimental approach while no incubation period is detected.The results showed that incubation period duration decreases with increasing diffusion coefficient.Additionally,when CO_(2) state is gas,rate of increasing diffusion coefficient with pressure is decreased with temperature and when CO_(2) state is supercritical,the rate of increasing diffusion coefficient with pressure is decreased significantly.
文摘Sandstone reservoirs often contain clay particles that can cause damage and reduce permeability during low-salinity water flooding.In this study,the effect of surfactants on fine migration in clay-rich sandstones and its impact on oil recovery was investigated.First,the impact of surfactants on interparticle forces in fine-matrix,fine-fine,and oil-matrix systems was modeled.The results showed that both CTAB(cetyltrimethyl ammonium bromide)and QS(quillaja saponin)cause EDL compaction,weakening the repulsive forces.However,SDS(sodium dodecyl sulfate)and TX(triton X-100)do not affect the EDL.Next,the effect of surfactants on IFT reduction and wettability alteration was experimentally investigated.All surfactants reduced IFT due to the surface excessive concentration mechanism.The wettability alteration experiment illustrated that although QS and CTAB compact EDL around oil and matrix particles leading to attraction force augmentation,they both alter wettability through adsorption on matrix and carboxylic groups present in crude oil,respectively.Surfactant aqueous solutions were then injected into various clay-rich sandstone sanpacks,which resulted in increased oil recovery.However,the mechanisms leading to enhanced oil recovery variedby surfactant type.CTAB increased recovery by 10%through IFT reduction and wettability alteration,while SDS and TX increased recovery by 12%and 9%,respectively,through wettability alteration and extreme fine migration.In contrast,partial fine migration in the QS flooding experiment reached a recovery increase of 18%.Permeability trends through experiments were also recorded.During CTAB injection,permeability did not reduce,while QS aqueous solution reduced rock permeability to 5 m D.SDS and TX reduced the magnitude of permeability to 2 m D.In conclusion,this study demonstrates that surfactants can effectively improve oil recovery in clay-rich sandstones by altering the interparticle forces,reducing IFT,and changing wettability.The results suggest that the type of surfactant used should be carefully selected to achieve the desired recovery increase without affecting the permeability of the reservoir.
文摘Floods and earthquakes are the most common natural disasters,causing significant damage and casualties in urban communities.Although academic research has focused on assessing cities'ability to withstand these natural disasters,there is a lack of established frameworks for evaluating resilience against multiple hazards.This research integrates the earthquake and flood resilience indicators to create a comprehensive resilience assess-ment framework.This study integrated seismic and flood resilience indicators and categorized them into 27 clusters.It also used the DEMATEL(Decision-Making Trial and Evaluation Laboratory)method to determine the significance of clusters and prioritize them.This research identified 13 cause clusters and 14 effect clusters of indicators for seismic and flood resilience.The‘response capacity'cluster has the most impact on seismic and flood resilience,while the‘transportation and accessibility'cluster is the most affected cluster.This article presents a framework for evaluating flood and seismic resilience and makes suggestions for future research.
基金This work was supported by the Portuguese Foundation for Science and Technology(FCT)(Grant No.PTDC/CTA-OHR/30561/2017)(WinTherface).
文摘A vertical slot fishway(VSF)is among the most effective and commonly used fishway structures to enable fish to pass through artificial barriers such as dams and weirs in the river.Nevertheless,such structures need further improvements in providing better swimming conditions for fish inside the pool and enhancing attraction at the entrance.Therefore,the main objective of this study was to investigate the influence of slope and whether integrating some cylinder structures inside the fishway could enhance further attraction and provide better swimming conditions for fish.This study consists of several numerical simulations,first considering the fishway without cylinder elements while testing three different slopes under two different discharges.Then,the same numerical simulations were conducted,considering cylinder elements of different diameters and arrangements inside the fishway.The numerical model was validated by comparing computed velocities with those measured experimentally from the literature.The results show that the maximum velocity and turbulent kinetic energy(TKE)in the main jet increase as the discharge increases on the same slope.The flow velocity and TKE decrease in the areas inside the pool and between the two baffles.Introducing cylinder elements inside the fishway reduces the principal flow’s maximum velocity.Also,inside the pool,low-velocity regions were expanding.A comparison between the design with a cylinder and the simple VSF indicates that the presence of a cylinder reduced the maximum velocities for the smallest and highest slopes by 6.21%and 9.86%on average,respectively.However,in terms of TKE,cylinders inside the fishway could provide better performance than simple VSF,mainly for low-flow conditions.Finally,this study’s solution-oriented findings provide insights that could help design cost-effective fishways by improving particularly fish attraction to the fishway.
基金All authors are inclined to appraise the laboratory facilities provided by petroleum engineering department of Amirkabir University of Technology(AUT)for this project.
文摘This study reports the applicability of quillaja saponin(QS)as a vigorous and environmentally friendly shale swelling inhibitor.QS is a natural surfactant,which is extracted from herbal sources.The inhibition strength of this surfactant was assessed through various experiments,such as sedimentation,inhibition,filtration,particle size,Scanning Electron Microscope(SEM)images,and cutting recovery.Data obtained from these tests illustrated that QS greatly inhibits clays from swelling.The optimal concentration for QS in this intend was 10 g/L.Compatibility of this surfactant with other common additives was also investigated,which showed that it is totally compatible.Finally,the potential inhibition mechanism was assessed through thermal gravimetric analysis(TGA),zeta potential,and contact angle measurement experiments.Surface coating,and wettability alteration of clay particles to the oil-wet state was recognized as the most probable mechanism.
