In this communication, the impacts of adding SDS （sodium dodecyl sulfate）, TBAF （tetra-n-butylammonlum tluorloe） ano the mixture of SDS ＋ TBAF on the main kinetic parameters of CO2 hydrate formation （induction t...In this communication, the impacts of adding SDS （sodium dodecyl sulfate）, TBAF （tetra-n-butylammonlum tluorloe） ano the mixture of SDS ＋ TBAF on the main kinetic parameters of CO2 hydrate formation （induction time, the quantity and rate of gas uptake, and storage capacity） were investigated. The tests were performed under stirring conditions at T = 5 ℃ and P = 3.8 MPa in a 169 cm3 batch reactor. The results show that adding SDS with a concentration of 400 ppm, TBAF with a concentration of l-5 wt%, and the mixture of SDS ＋ TBAF, would increase the storage capacity of CO2 hydrate and the quantity of gas uptake, and decrease the induction time of hydrate formation process. The addition of 5 wt% of TBAF and 400 ppm of SDS would increase the CO2 hydrate storage capacity by 86.1% and 81.6%, respectively, compared to pure water. Investigation of the impact of SDS, TBAF and their mixture on the rate of gas uptake indicates that the mixture of SDS ＋ TBAF does not have a significant effect on the rate of gas uptake during hydrate formation process.展开更多
In this paper, the effect of adding different concentrations of kinetic inhibitors on the induction time of hydrogen sulfide hydrate formation in a reactor equipped with automatic adjustable temperature controller is ...In this paper, the effect of adding different concentrations of kinetic inhibitors on the induction time of hydrogen sulfide hydrate formation in a reactor equipped with automatic adjustable temperature controller is studied. A novel method namely ＂sudden cooling＂ is used for performing the relevant measurements, in which the induction time of H2S hydrate in the presence/absence of PVP and L-tyrosine with different concentrations （100, 500, and 1000 ppm） is determined. As a result, PVP with the concentration of 1000 ppm in aqueous solution is detected as a more suitable material for increasing the induction time of H2S hydrate formation among the investigated kinetic hydrate inhibitors.展开更多
The assumptions and models for solubility modelling or prediction in systems using nonpolar solvents, or water and complex triterpene and other active pharmaceutical ingredients as solutes aren't well studied. Fur...The assumptions and models for solubility modelling or prediction in systems using nonpolar solvents, or water and complex triterpene and other active pharmaceutical ingredients as solutes aren't well studied. Furthermore, the assumptions concerning heat capacity effects(negligibility, experimental values or approximations) are explored, using non-polar solvents(benzene), or water as reference solvents, for systems with solute melting points in the range of 306–528 K and molecular weights in the range of 90–442 g/mol. New empirical estimation methods for the Δ_(fus)C_(pi) of APIs are presented which correlate the solute molecular masses and van der Waals surface areas with Δ_(fus)C_(pi). Separate empirical parameters were required for oxygenated and non-oxygenated solutes. Subsequently, the predictive capabilities of the various approaches to solubility modelling for complex pharmaceuticals,for which data is limited, are analysed. The solute selection is based on a principal component analysis, considering molecular weights, fusion temperatures, and solubilities in a non-polar solvent, alcohol, and water, where data was available. New NRTL-SAC parameters were determined for selected steroids, by regression. The original UNIFAC, modified UNIFAC(Dortmund), COSMO-RS(OL), and COSMO-SAC activity coefficient predictions are then conducted, based on the availability of group constants and sigma profiles. These are undertaken to assess the predictive capabilities of these models when each assumption concerning heat capacity is employed. The predictive qualities of the models are assessed, based on the mean square deviation and provide guidelines for model selection, and assumptions concerning phase equilibrium, when designing solid–liquid separators for the pharmaceutical industry on process simulation software. The most suitable assumption regarding Δ_(fus)C_(pi) was found to be system specific, with modified UNIFAC(Dortmund) performing well in benzene as a solvent system, while original UNIFAC performs better in aqueous systems.Original UNIFAC outperforms other predictive models tested in the triterpene/steroidal systems,with no significant influence from the assumptions regarding Δ_(fus)C_(pi).展开更多
An endoreversible model is used to simulate the dynamic behavior of a solar driven absorption refrigerator, the cycle under different operating and design conditions. A global time minimization procedure is performed ...An endoreversible model is used to simulate the dynamic behavior of a solar driven absorption refrigerator, the cycle under different operating and design conditions. A global time minimization procedure is performed to reach maximum performances. To evaluate the influence of the cold temperature on the system’s performances, results are carried out for three values of this temperature. They are presented in normalized charts for general applications. The minimum time set point temperature, entropy and maximum refrigeration load are sharp and therefore, are important to be considered for system design.展开更多
The remained oil in the reservoir after conventional water-flooding processes,forms a dispersed phase in the form of oil drops which is trapped by capillary forces and is almost about 70%of the original oil in the pla...The remained oil in the reservoir after conventional water-flooding processes,forms a dispersed phase in the form of oil drops which is trapped by capillary forces and is almost about 70%of the original oil in the place(OOIP).To reduce oil residual saturation in laboratory experiments and field projects,surfactant flooding is effective via decreasing the interfacial tension mobility ratio between oil and water phases.Estimation of the role of design variables,like chemical concentrations,partition coefficient and injection rate in different performance quantities,considering a heterogeneous and multiphase oil reservoir is a critical stage for optimal design.Increasing demand for oil production from water-flooded reservoirs has caused an increasing interest in surfactant-polymer(SP)and alkali-surfactant-polymer(ASP).Modeling minimizes the risk of high cost of chemicals by improving our insight of process.In the present paper,a surfactant compositional flood model for a three-component(water,petroleum and surfactant),two phase(aqueous and oleic)system is studied.A homogeneous,two-dimensional,isothermal reservoir with no free gas or alkali is assumed.The governing equations are in three categories:the continuity equations for the transport of each component,Darcy's equation for the transport of each phase and other auxiliary equations.The equations are solved by finite-differences using a procedure implicit in pressure and explicit in saturation.The validation of the model is achieved through comparing the modeling results with CMG simulators and BuckleyeLeverett theory.The results of modeling showed good agreement with CMG results,and the comparison with BuckleyeLeverett theory is explained according to different assumptions.After validation of the model,in order to investigate sensitivity analysis,the effects of system variables(partition coefficient,surface tension,oil viscosity and surface injection concentration)and performance variable(cumulative oil recovery)are studied.Finally,the comparison of oil recovery between water-flooding and surfactant-flooding was done.The results showed higher oil recovery with changes in capillary number when the partition coefficient is greater than unity.Increasing oil viscosity resulted in decreasing the oil recovery by changing in fractional flow.Moreover,it was concluded that the oil recovery was enhanced by increasing surfactant injection concentration.The oil recovery was increased when surfactant was injected to the system and this result was obtained by comparing water-flooding and surfactantflooding.展开更多
Steam Assisted Gravity Drainage(SAGD)as a successful enhanced oil recovery(EOR)process has been applied to extract heavy and extra heavy oils.Huge amount of global heavy oil resources exists in carbonate reservoirs wh...Steam Assisted Gravity Drainage(SAGD)as a successful enhanced oil recovery(EOR)process has been applied to extract heavy and extra heavy oils.Huge amount of global heavy oil resources exists in carbonate reservoirs which are mostly naturally fractured reservoirs.Unlike clastic reservoirs,few studies were carried out to determine the performance of SAGD in carbonate reservoirs.Even though SAGD is a highly promising technique,several uncertainties and unanswered questions still exist and they should be clarified for expansion of SAGD methods to world wide applications especially in naturally fractured reservoirs.In this communication,the effects of some operational and reservoir parameters on SAGD processes were investigated in a naturally fractured reservoir with oil wet rock using CMG-STARS thermal simulator.The purpose of this study was to investigate the role of fracture properties including fracture orientation,fracture spacing and fracture permeability on the SAGD performance in naturally fractured reservoirs.Moreover,one operational parameter was also studied;one new well configuration,staggered well pair was evaluated.Results indicated that fracture orientation influences steam expansion and oil production from the horizontal well pairs.It was also found that horizontal fractures have unfavorable effects on oil production,while vertical fractures increase the production rate for the horizontal well.Moreover,an increase in fracture spacing results in more oil production,because in higher fracture spacing model,steam will have more time to diffuse into matrices and heat up the entire reservoir.Furthermore,an increase in fracture permeability results in process enhancement and ultimate recovery improvement.Besides,diagonal change in the location of injection wells(staggered model)increases the recovery efficiency in long-term production plan.展开更多
Controlling sand production in the petroleum industry has been a long-standing problem for more than 70 years.To provide technical support for sand control strategy,it is necessary to predict the conditions at which s...Controlling sand production in the petroleum industry has been a long-standing problem for more than 70 years.To provide technical support for sand control strategy,it is necessary to predict the conditions at which sanding occurs.To this end,for the first time,least square support machine(LSSVM)classification approach,as a novel technique,is applied to identify the conditions under which sand production occurs.The model presented in this communication takes into account different parameters that may play a role in sanding.The performance of proposed LSSVM model is examined using field data reported in open literature.It is shown that the developed model can accurately predict the sand production in a real field.The results of this study indicates that implementation of LSSVM modeling can effectively help completion designers to make an on time sand control plan with least deterioration of production.展开更多
基金financial support from the Iran National Science Foundation
文摘In this communication, the impacts of adding SDS （sodium dodecyl sulfate）, TBAF （tetra-n-butylammonlum tluorloe） ano the mixture of SDS ＋ TBAF on the main kinetic parameters of CO2 hydrate formation （induction time, the quantity and rate of gas uptake, and storage capacity） were investigated. The tests were performed under stirring conditions at T = 5 ℃ and P = 3.8 MPa in a 169 cm3 batch reactor. The results show that adding SDS with a concentration of 400 ppm, TBAF with a concentration of l-5 wt%, and the mixture of SDS ＋ TBAF, would increase the storage capacity of CO2 hydrate and the quantity of gas uptake, and decrease the induction time of hydrate formation process. The addition of 5 wt% of TBAF and 400 ppm of SDS would increase the CO2 hydrate storage capacity by 86.1% and 81.6%, respectively, compared to pure water. Investigation of the impact of SDS, TBAF and their mixture on the rate of gas uptake indicates that the mixture of SDS ＋ TBAF does not have a significant effect on the rate of gas uptake during hydrate formation process.
文摘In this paper, the effect of adding different concentrations of kinetic inhibitors on the induction time of hydrogen sulfide hydrate formation in a reactor equipped with automatic adjustable temperature controller is studied. A novel method namely ＂sudden cooling＂ is used for performing the relevant measurements, in which the induction time of H2S hydrate in the presence/absence of PVP and L-tyrosine with different concentrations （100, 500, and 1000 ppm） is determined. As a result, PVP with the concentration of 1000 ppm in aqueous solution is detected as a more suitable material for increasing the induction time of H2S hydrate formation among the investigated kinetic hydrate inhibitors.
基金supported by the National Research Foundation of South Africa under the South African Research Chair Initiative of the Department of Science and Technology and the National Research Foundation Research and Innovation Support and Advancement (RISA) program
文摘The assumptions and models for solubility modelling or prediction in systems using nonpolar solvents, or water and complex triterpene and other active pharmaceutical ingredients as solutes aren't well studied. Furthermore, the assumptions concerning heat capacity effects(negligibility, experimental values or approximations) are explored, using non-polar solvents(benzene), or water as reference solvents, for systems with solute melting points in the range of 306–528 K and molecular weights in the range of 90–442 g/mol. New empirical estimation methods for the Δ_(fus)C_(pi) of APIs are presented which correlate the solute molecular masses and van der Waals surface areas with Δ_(fus)C_(pi). Separate empirical parameters were required for oxygenated and non-oxygenated solutes. Subsequently, the predictive capabilities of the various approaches to solubility modelling for complex pharmaceuticals,for which data is limited, are analysed. The solute selection is based on a principal component analysis, considering molecular weights, fusion temperatures, and solubilities in a non-polar solvent, alcohol, and water, where data was available. New NRTL-SAC parameters were determined for selected steroids, by regression. The original UNIFAC, modified UNIFAC(Dortmund), COSMO-RS(OL), and COSMO-SAC activity coefficient predictions are then conducted, based on the availability of group constants and sigma profiles. These are undertaken to assess the predictive capabilities of these models when each assumption concerning heat capacity is employed. The predictive qualities of the models are assessed, based on the mean square deviation and provide guidelines for model selection, and assumptions concerning phase equilibrium, when designing solid–liquid separators for the pharmaceutical industry on process simulation software. The most suitable assumption regarding Δ_(fus)C_(pi) was found to be system specific, with modified UNIFAC(Dortmund) performing well in benzene as a solvent system, while original UNIFAC performs better in aqueous systems.Original UNIFAC outperforms other predictive models tested in the triterpene/steroidal systems,with no significant influence from the assumptions regarding Δ_(fus)C_(pi).
文摘An endoreversible model is used to simulate the dynamic behavior of a solar driven absorption refrigerator, the cycle under different operating and design conditions. A global time minimization procedure is performed to reach maximum performances. To evaluate the influence of the cold temperature on the system’s performances, results are carried out for three values of this temperature. They are presented in normalized charts for general applications. The minimum time set point temperature, entropy and maximum refrigeration load are sharp and therefore, are important to be considered for system design.
文摘The remained oil in the reservoir after conventional water-flooding processes,forms a dispersed phase in the form of oil drops which is trapped by capillary forces and is almost about 70%of the original oil in the place(OOIP).To reduce oil residual saturation in laboratory experiments and field projects,surfactant flooding is effective via decreasing the interfacial tension mobility ratio between oil and water phases.Estimation of the role of design variables,like chemical concentrations,partition coefficient and injection rate in different performance quantities,considering a heterogeneous and multiphase oil reservoir is a critical stage for optimal design.Increasing demand for oil production from water-flooded reservoirs has caused an increasing interest in surfactant-polymer(SP)and alkali-surfactant-polymer(ASP).Modeling minimizes the risk of high cost of chemicals by improving our insight of process.In the present paper,a surfactant compositional flood model for a three-component(water,petroleum and surfactant),two phase(aqueous and oleic)system is studied.A homogeneous,two-dimensional,isothermal reservoir with no free gas or alkali is assumed.The governing equations are in three categories:the continuity equations for the transport of each component,Darcy's equation for the transport of each phase and other auxiliary equations.The equations are solved by finite-differences using a procedure implicit in pressure and explicit in saturation.The validation of the model is achieved through comparing the modeling results with CMG simulators and BuckleyeLeverett theory.The results of modeling showed good agreement with CMG results,and the comparison with BuckleyeLeverett theory is explained according to different assumptions.After validation of the model,in order to investigate sensitivity analysis,the effects of system variables(partition coefficient,surface tension,oil viscosity and surface injection concentration)and performance variable(cumulative oil recovery)are studied.Finally,the comparison of oil recovery between water-flooding and surfactant-flooding was done.The results showed higher oil recovery with changes in capillary number when the partition coefficient is greater than unity.Increasing oil viscosity resulted in decreasing the oil recovery by changing in fractional flow.Moreover,it was concluded that the oil recovery was enhanced by increasing surfactant injection concentration.The oil recovery was increased when surfactant was injected to the system and this result was obtained by comparing water-flooding and surfactantflooding.
文摘Steam Assisted Gravity Drainage(SAGD)as a successful enhanced oil recovery(EOR)process has been applied to extract heavy and extra heavy oils.Huge amount of global heavy oil resources exists in carbonate reservoirs which are mostly naturally fractured reservoirs.Unlike clastic reservoirs,few studies were carried out to determine the performance of SAGD in carbonate reservoirs.Even though SAGD is a highly promising technique,several uncertainties and unanswered questions still exist and they should be clarified for expansion of SAGD methods to world wide applications especially in naturally fractured reservoirs.In this communication,the effects of some operational and reservoir parameters on SAGD processes were investigated in a naturally fractured reservoir with oil wet rock using CMG-STARS thermal simulator.The purpose of this study was to investigate the role of fracture properties including fracture orientation,fracture spacing and fracture permeability on the SAGD performance in naturally fractured reservoirs.Moreover,one operational parameter was also studied;one new well configuration,staggered well pair was evaluated.Results indicated that fracture orientation influences steam expansion and oil production from the horizontal well pairs.It was also found that horizontal fractures have unfavorable effects on oil production,while vertical fractures increase the production rate for the horizontal well.Moreover,an increase in fracture spacing results in more oil production,because in higher fracture spacing model,steam will have more time to diffuse into matrices and heat up the entire reservoir.Furthermore,an increase in fracture permeability results in process enhancement and ultimate recovery improvement.Besides,diagonal change in the location of injection wells(staggered model)increases the recovery efficiency in long-term production plan.
文摘Controlling sand production in the petroleum industry has been a long-standing problem for more than 70 years.To provide technical support for sand control strategy,it is necessary to predict the conditions at which sanding occurs.To this end,for the first time,least square support machine(LSSVM)classification approach,as a novel technique,is applied to identify the conditions under which sand production occurs.The model presented in this communication takes into account different parameters that may play a role in sanding.The performance of proposed LSSVM model is examined using field data reported in open literature.It is shown that the developed model can accurately predict the sand production in a real field.The results of this study indicates that implementation of LSSVM modeling can effectively help completion designers to make an on time sand control plan with least deterioration of production.
