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Papers by Cecilia Duran-valencia
The adsorption of surfactants (DTAB, SDS, and CAPB) at the calcite−water interface was studied th... more The adsorption of surfactants (DTAB, SDS, and CAPB) at the calcite−water interface was studied through surface zeta potential measurements and multiscale molecular dynamics. The ground-state polarization of surfactants proved to be a key factor for the observed behavior; correlation was found between adsorption and the hard or sof t charge distribution of the amphiphile. SDS exhibits a steep aggregation profile, reaching saturation and showing classic ionic-surfactant behavior. In contrast, DTAB and CAPB featured diversified adsorption profiles, suggesting interplay between supramolec-ular aggregation and desorption from the solid surface and alleviating charge buildup at the carbonate surface when bulk concentration approaches CMC. This manifests as an adsorption profile with a fast initial step, followed by a metastable plateau and finalizing with a sharp decrease and stabilization of surface charge. Suggesting this competition of equilibria, elicited at the CaCO 3 surface, this study provides atomistic insight into the adsorption mechanism for ionic surfactants on calcite, which is in accordance with experimental evidence and which is a relevant criterion for developing enhanced oil recovery processes.
Chemical Engineering Communications, 2006
In this study we propose a method for phase stability analysis at pressure and temperature specif... more In this study we propose a method for phase stability analysis at pressure and temperature specifications, in the frame of a ''volume-based'' thermodynamics. The formulation of the tangent plane distance (TPD) criterion in terms of the Helmholtz free energy is used in this work for testing phase thermodynamic stability at p-T conditions, using component molar densities as primary variables. The phase stability problem is non-convex; the TPD function may exhibit multiple local minima and saddle points, the use of global optimization methods for its minimization being appropriate. For the unconstrained minimization of the TPD function we use the tunneling global optimization method, which has shown its ability in efficiently solving difficult non-convex, highly nonlinear problems. The method is tested for a variety of mixtures ranging from binaries to mixtures with many components, with emphasis on difficult conditions. The proposed method proved to be an efficient and reliable tool for phase stability analysis.
Modeling and Simulation in Engineering Sciences, 2016
Langmuir, 2016
The adsorption of surfactants (DTAB, SDS, and CAPB) at the calcite-water interface was studied th... more The adsorption of surfactants (DTAB, SDS, and CAPB) at the calcite-water interface was studied through surface zeta potential measurements and multiscale molecular dynamics. The ground-state polarization of surfactants proved to be a key factor for the observed behavior; correlation was found between adsorption and the hard or soft charge distribution of the amphiphile. SDS exhibits a steep aggregation profile, reaching saturation and showing classic ionic-surfactant behavior. In contrast, DTAB and CAPB featured diversified adsorption profiles, suggesting interplay between supramolecular aggregation and desorption from the solid surface and alleviating charge buildup at the carbonate surface when bulk concentration approaches CMC. This manifests as an adsorption profile with a fast initial step, followed by a metastable plateau and finalizing with a sharp decrease and stabilization of surface charge. Suggesting this competition of equilibria, elicited at the CaCO3 surface, this study provides atomistic insight into the adsorption mechanism for ionic surfactants on calcite, which is in accordance with experimental evidence and which is a relevant criterion for developing enhanced oil recovery processes.
Polymer Journal, 2014
In this paper, we describe the synthesis, characterization and evaluation of nanocomposite prefor... more In this paper, we describe the synthesis, characterization and evaluation of nanocomposite preformed particle gels (PPGs) for use as conformance control agents in high-temperature and high-salinity oil reservoirs. The chemical stability of conventional acrylamide (AM)-homopolymer-based PPGs was improved by incorporating an optimized ratio of new functional groups into their structure to withstand harsh reservoir conditions. The modified PPGs were synthesized via free radical crosslinking polymerization at room temperature using AM, vinylpyrrolidone (VP) and 2-acrylamido-2-methylpropane sulfonic sodium salt (AMPSNa) monomers and an N,N-methylenebis (acrylamide) (MBA) crosslinker. The mechanical properties of the PPGs were enhanced by adding a dispersion of modified bentonite (MB) to the formulation. The chemical and mechanical stabilities of the synthesized PPGs were evaluated at a high temperature (130 1C) and under high-salinity conditions using production water (with a TDS of 83 942.63 p.p.m.) and connate water (with a TDS of 254 873.09 p.p.m.), both of which were collected from an oil reservoir. The experimental results showed that PPGs prepared with 30 wt.% of a 1:1:1 molar mass ratio of AM, VP and AMPS monomers with 0.5 wt.% MBA and 2 wt.% MB exhibited the highest stability of the investigated PPGs under oil reservoir conditions.
Energy & Fuels, 2009
Dynamic displacement experiments, simulating temperature and pressure conditions of an oil-bearin... more Dynamic displacement experiments, simulating temperature and pressure conditions of an oil-bearing formation during primary production stage, were carried out to investigate the processes of asphaltene-induced precipitation and deposition during pressure depletion on a core sample and their effects on the absolute permeability. A representative monophasic-bottom-hole fluid sample and one core of consolidated Bedford limestone were used in coreflood tests. To identify the pressure and temperature conditions at which the asphaltene will begin to precipitate, as well as the bubble-point pressures of the reservoir fluid sample, the light-scattering technique solid detection system (SDS) using a variable volume, visual PVT cell was used. The coreflood test results indicated that the in situ asphaltene precipitation and deposition on porous medium damage absolute permeability and reduce effective porosity as reservoir fluid pressure is reduced until a point near bubble-point pressure. Core impairment, resulting from asphaltene deposition, was found to cause a 24% and 20% loss of initial oil permeability and effective porosity, respectively. A mathematical model, based on the transport of stable particulate suspensions in porous media, for asphaltene deposition was developed and validated directly with experimental results obtained in this investigation, as well as those found in the literature. On the basis of the developed mathematical model, two distinct mechanisms were identified as a consequence of the deposition process, namely, asphaltene adsorption and trapping. The porous medium was represented as a network of sites and bonds, with pore bodies identified as sites and pore throats as bonds. A satisfactory qualitative agreement was observed with the experimental results.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2009
In this work, a set of experiments was carried out with the purpose of studying the adsorption me... more In this work, a set of experiments was carried out with the purpose of studying the adsorption mechanisms involved in the interfacial interaction of the asphaltene/mineral system at high asphaltene concentrations. Adsorption isotherms of asphaltenes were obtained by contacting samples of Berea sandstone, Bedford limestone, and a Mexican dolomite rock with an asphaltene fraction dissolved in toluene. The asphaltene sample was obtained from a Mexican heavy crude oil. At low concentrations, the typical shape of asphaltene adsorption isotherms is similar as that reported in the literature, while at higher concentrations it was found a stepwise-type isotherm, which suggest a qualitative change in the adsorption behavior. Such changes are related to the asphaltene association and their aggregation. According to previous works, at low concentrations, the isotherm model of Marczewski and Szymula adjust adequately the monolayertype adsorption behavior. In order to understand the adsorption behavior at higher concentrations, it is proposed the model of Zhu and Gu for fitting the whole isotherm, with two adsorption steps (monolayer and monolayer to multilayer adsorption). This last model presumes that the substance is able to undergo clustering, which seems to be the case for asphaltenes; the adsorption data obtained in this work seem to agree with the model of Zhu and Gu.
Energy & Fuels, 2009
... Ricardo Macías-Salinas* ‡ , Cecilia Durán-Valencia § , Simón López-Ramírez and Christian... more ... Ricardo Macías-Salinas* ‡ , Cecilia Durán-Valencia § , Simón López-Ramírez and Christian Bouchot ‡. Escuela Superior de Ingeniería Química e Industrias Extractivas (ESIQIE), Departamento de Ingeniería Química, Instituto ...
The adsorption of surfactants (DTAB, SDS, and CAPB) at the calcite−water interface was studied th... more The adsorption of surfactants (DTAB, SDS, and CAPB) at the calcite−water interface was studied through surface zeta potential measurements and multiscale molecular dynamics. The ground-state polarization of surfactants proved to be a key factor for the observed behavior; correlation was found between adsorption and the hard or sof t charge distribution of the amphiphile. SDS exhibits a steep aggregation profile, reaching saturation and showing classic ionic-surfactant behavior. In contrast, DTAB and CAPB featured diversified adsorption profiles, suggesting interplay between supramolec-ular aggregation and desorption from the solid surface and alleviating charge buildup at the carbonate surface when bulk concentration approaches CMC. This manifests as an adsorption profile with a fast initial step, followed by a metastable plateau and finalizing with a sharp decrease and stabilization of surface charge. Suggesting this competition of equilibria, elicited at the CaCO 3 surface, this study provides atomistic insight into the adsorption mechanism for ionic surfactants on calcite, which is in accordance with experimental evidence and which is a relevant criterion for developing enhanced oil recovery processes.
Chemical Engineering Communications, 2006
In this study we propose a method for phase stability analysis at pressure and temperature specif... more In this study we propose a method for phase stability analysis at pressure and temperature specifications, in the frame of a ''volume-based'' thermodynamics. The formulation of the tangent plane distance (TPD) criterion in terms of the Helmholtz free energy is used in this work for testing phase thermodynamic stability at p-T conditions, using component molar densities as primary variables. The phase stability problem is non-convex; the TPD function may exhibit multiple local minima and saddle points, the use of global optimization methods for its minimization being appropriate. For the unconstrained minimization of the TPD function we use the tunneling global optimization method, which has shown its ability in efficiently solving difficult non-convex, highly nonlinear problems. The method is tested for a variety of mixtures ranging from binaries to mixtures with many components, with emphasis on difficult conditions. The proposed method proved to be an efficient and reliable tool for phase stability analysis.
Modeling and Simulation in Engineering Sciences, 2016
Langmuir, 2016
The adsorption of surfactants (DTAB, SDS, and CAPB) at the calcite-water interface was studied th... more The adsorption of surfactants (DTAB, SDS, and CAPB) at the calcite-water interface was studied through surface zeta potential measurements and multiscale molecular dynamics. The ground-state polarization of surfactants proved to be a key factor for the observed behavior; correlation was found between adsorption and the hard or soft charge distribution of the amphiphile. SDS exhibits a steep aggregation profile, reaching saturation and showing classic ionic-surfactant behavior. In contrast, DTAB and CAPB featured diversified adsorption profiles, suggesting interplay between supramolecular aggregation and desorption from the solid surface and alleviating charge buildup at the carbonate surface when bulk concentration approaches CMC. This manifests as an adsorption profile with a fast initial step, followed by a metastable plateau and finalizing with a sharp decrease and stabilization of surface charge. Suggesting this competition of equilibria, elicited at the CaCO3 surface, this study provides atomistic insight into the adsorption mechanism for ionic surfactants on calcite, which is in accordance with experimental evidence and which is a relevant criterion for developing enhanced oil recovery processes.
Polymer Journal, 2014
In this paper, we describe the synthesis, characterization and evaluation of nanocomposite prefor... more In this paper, we describe the synthesis, characterization and evaluation of nanocomposite preformed particle gels (PPGs) for use as conformance control agents in high-temperature and high-salinity oil reservoirs. The chemical stability of conventional acrylamide (AM)-homopolymer-based PPGs was improved by incorporating an optimized ratio of new functional groups into their structure to withstand harsh reservoir conditions. The modified PPGs were synthesized via free radical crosslinking polymerization at room temperature using AM, vinylpyrrolidone (VP) and 2-acrylamido-2-methylpropane sulfonic sodium salt (AMPSNa) monomers and an N,N-methylenebis (acrylamide) (MBA) crosslinker. The mechanical properties of the PPGs were enhanced by adding a dispersion of modified bentonite (MB) to the formulation. The chemical and mechanical stabilities of the synthesized PPGs were evaluated at a high temperature (130 1C) and under high-salinity conditions using production water (with a TDS of 83 942.63 p.p.m.) and connate water (with a TDS of 254 873.09 p.p.m.), both of which were collected from an oil reservoir. The experimental results showed that PPGs prepared with 30 wt.% of a 1:1:1 molar mass ratio of AM, VP and AMPS monomers with 0.5 wt.% MBA and 2 wt.% MB exhibited the highest stability of the investigated PPGs under oil reservoir conditions.
Energy & Fuels, 2009
Dynamic displacement experiments, simulating temperature and pressure conditions of an oil-bearin... more Dynamic displacement experiments, simulating temperature and pressure conditions of an oil-bearing formation during primary production stage, were carried out to investigate the processes of asphaltene-induced precipitation and deposition during pressure depletion on a core sample and their effects on the absolute permeability. A representative monophasic-bottom-hole fluid sample and one core of consolidated Bedford limestone were used in coreflood tests. To identify the pressure and temperature conditions at which the asphaltene will begin to precipitate, as well as the bubble-point pressures of the reservoir fluid sample, the light-scattering technique solid detection system (SDS) using a variable volume, visual PVT cell was used. The coreflood test results indicated that the in situ asphaltene precipitation and deposition on porous medium damage absolute permeability and reduce effective porosity as reservoir fluid pressure is reduced until a point near bubble-point pressure. Core impairment, resulting from asphaltene deposition, was found to cause a 24% and 20% loss of initial oil permeability and effective porosity, respectively. A mathematical model, based on the transport of stable particulate suspensions in porous media, for asphaltene deposition was developed and validated directly with experimental results obtained in this investigation, as well as those found in the literature. On the basis of the developed mathematical model, two distinct mechanisms were identified as a consequence of the deposition process, namely, asphaltene adsorption and trapping. The porous medium was represented as a network of sites and bonds, with pore bodies identified as sites and pore throats as bonds. A satisfactory qualitative agreement was observed with the experimental results.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2009
In this work, a set of experiments was carried out with the purpose of studying the adsorption me... more In this work, a set of experiments was carried out with the purpose of studying the adsorption mechanisms involved in the interfacial interaction of the asphaltene/mineral system at high asphaltene concentrations. Adsorption isotherms of asphaltenes were obtained by contacting samples of Berea sandstone, Bedford limestone, and a Mexican dolomite rock with an asphaltene fraction dissolved in toluene. The asphaltene sample was obtained from a Mexican heavy crude oil. At low concentrations, the typical shape of asphaltene adsorption isotherms is similar as that reported in the literature, while at higher concentrations it was found a stepwise-type isotherm, which suggest a qualitative change in the adsorption behavior. Such changes are related to the asphaltene association and their aggregation. According to previous works, at low concentrations, the isotherm model of Marczewski and Szymula adjust adequately the monolayertype adsorption behavior. In order to understand the adsorption behavior at higher concentrations, it is proposed the model of Zhu and Gu for fitting the whole isotherm, with two adsorption steps (monolayer and monolayer to multilayer adsorption). This last model presumes that the substance is able to undergo clustering, which seems to be the case for asphaltenes; the adsorption data obtained in this work seem to agree with the model of Zhu and Gu.
Energy & Fuels, 2009
... Ricardo Macías-Salinas* ‡ , Cecilia Durán-Valencia § , Simón López-Ramírez and Christian... more ... Ricardo Macías-Salinas* ‡ , Cecilia Durán-Valencia § , Simón López-Ramírez and Christian Bouchot ‡. Escuela Superior de Ingeniería Química e Industrias Extractivas (ESIQIE), Departamento de Ingeniería Química, Instituto ...