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Papers by David Caetano Santos

Research paper thumbnail of Solubility parameter of oils by several models and experimental oil compatibility data: implications for asphaltene stability

Petroleum Science and Technology, Apr 3, 2019

In a previous study we obtained reference values of solubility parameter of two Brazilian crude o... more In a previous study we obtained reference values of solubility parameter of two Brazilian crude oils based on asphaltene flocculation data. In this work, these reference values were compared to those obtained by nine models available in the literature and oil compatibility data were experimentally obtained to enhance the modeling evaluation. These evaluations allowed to select models to predict asphaltene stability and oil compatibility. As a result, only our method along with three other methods can accurately predict the experimental results of the compatibility between oil mixtures, and the conclusion is that usually recommended models are not the best choice.

Research paper thumbnail of Solubility parameter of narrow oil cuts by several models: quantifying the discrepancy among predictions for heavy cuts

Brazilian Journal of Chemical Engineering, Sep 30, 2021

In this study, the performance of nine models was evaluated in predicting the solubility paramete... more In this study, the performance of nine models was evaluated in predicting the solubility parameter of oil cuts. The oil cuts were generated from simulated distillation curves assuming a constant Watson factor. Five oils from different Brazilian geographic regions were used. It was observed that predictions diverge mainly for cuts having boiling points above 460 K. For instance, the maximum difference in the solubility parameter of the same cut can reach 9.8 MPa1/2 depending on the model used. For extrapolated results, this difference can reach 17.6 MPa1/2. The coherence of model extrapolations for heavier cuts was also evaluated. Furthermore, the volume additivity hypothesis of the solubility parameter was also assessed by comparing volume-averaged solubility parameters with the corresponding bulk solubility parameter of oils. In general, it was found that volumetric additivity is an acceptable simplification and, for the same oil, the maximum difference between the two ways of calculating the oil solubility parameter did not exceed 1.4 MPa1/2.

Research paper thumbnail of Prediction of speed of sound in compressed hydrocarbon and CO2 mixtures: theory comparison

Brazilian Journal of Chemical Engineering, Dec 20, 2022

Research paper thumbnail of Density of <i>n</i>-Heptane + <i>n</i>-Dodecane and Carbon Dioxide + <i>n</i>-Heptane + <i>n</i>-Dodecane Mixtures up to 70 MPa from (293.15 to 363.15) K

Journal of Chemical & Engineering Data, Feb 3, 2021

Density measurements of the n-heptane + n-dodecane binary mixture were performed with a vibrating... more Density measurements of the n-heptane + n-dodecane binary mixture were performed with a vibrating tube densitometer in the temperature range of (293.15 to 363.15) K and pressure up to 70 MPa at six...

Research paper thumbnail of Experimental and modeling studies of density and viscosity behavior of a live fluid due to CO2injection at reservoir condition

Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles

In this study, highly accurate measurements of density and dynamic viscosities of a recombined li... more In this study, highly accurate measurements of density and dynamic viscosities of a recombined live oil and its mixture with additional CO2were performed. The experiments were carried out under pressure and temperature gradients found in Brazilian Pre-salt reservoirs, that is, in the pressure range from (27.6 to 68.9) MPa and at (333.15 and 353.15) K. The assumption of volume change on mixing is evaluated from the experimental results, and the influence of pressure and temperature on the volume change upon mixing is assessed. The densities of mixtures are calculated considering (i) the excess volume approach, and (ii) no volume change. The densities are better correlated using the excess volume approach with Average Absolute Deviations (AAD) of 0.03%. Thirteen mixing rules of viscosity are examined by comparing the predicted values with the experimental viscosity of the recombined live oil + CO2mixture. The performance of some rules using compositional fractions (molar, volume and w...

Research paper thumbnail of Interfacial properties of asphaltene–brine systems and analysis of adsorption kinetics: effects of ion and water injection for EOR

Brazilian Journal of Chemical Engineering

Research paper thumbnail of Brazilian Pre Salt Oil CO2-RICH Unconcentional Phase Behavior: Experimental PVT and Modeling

Rio Oil and Gas Expo and Conference

Research paper thumbnail of Avaliação Da Metodologia De Determinação Do Inicio Da Precipitação Dos Asfaltenos Em Petróleos Utilizando FT-Nir

O ponto de inicio de precipitacao dos asfaltenos, IP, e definido como a quantidade minima do prec... more O ponto de inicio de precipitacao dos asfaltenos, IP, e definido como a quantidade minima do precipitante, em geral n-heptano, adicionado ao petroleo para que ocorra a precipitacao dos asfaltenos. E observado que este fenomeno esta associado a fatores cineticos inerentes ao sistema, fato ate entao nao mensurado adequadamente nas modelagens de comportamento dos asfaltenos. Neste contexto, a abundantemente usada tecnica de determinacao de inicio de precipitacao dos asfaltenos utilizando espectroscopia de NIR (near infrared) e investigada. Sao demonstradas quantidades significativas de informacoes adicionais acerca da utilizacao desta tecnica, como por exemplo, o efeito da taxa de adicao de n-heptano ao petroleo. Neste trabalho sao utilizadas duas amostras de petroleo denominadas P1 e P2, com distintas caracteristicas fisico-quimicas, onde se determina que os valores de IP variaram entre 2,59 3,25 e 0,56 1,2 ml de heptano/g de petroleo, respectivamente, a depender da vazao utilizada. A...

Research paper thumbnail of Solubility Parameter from an Acoustic Method: Temperature Effect and Applications to Petroleum

Chemical Engineering & Technology, 2020

Research paper thumbnail of Asphaltene flocculation parameter in Brazilian crude oils and synthetic polar and nonpolar mixtures: Experimental and modeling

Fuel, 2017

Abstract The experimental method used to predict solubility parameter of Brazilian crude oils tak... more Abstract The experimental method used to predict solubility parameter of Brazilian crude oils takes into account the critical solubility parameter assumption. In this work, experimental ratifications to this assumption were found for both crude oils and nonpolar asphaltene mixtures. This is an important matter since the oil compatibility is estimated from this assumption. Models based on the Regular Solution and Flory-Huggins theories were used to estimate the solubility data of least-soluble asphaltenes. Thereby, it was observed that the employment of Kikic modification of the Flory-Huggins combinatorial term plus the replacement of the traditional Hildebrand solubility parameter by the Hansen solubility parameter in the energetic term greatly improved the performance of these models and led to the best correlation, even for polar and associative solvents. In addition, the impact of asphaltene blending on Brazilian oil stability was evaluated from two asphaltene fractions sequentially extracted. The results point out that the asphaltene subfractionation should be taken into account in the solubility modeling. From these results, a critical solubility parameter for Brazilian oils (16.8 MPa 1/2 ) is proposed to be used as a universal input parameter in the experimental methodology of predicting solubility parameter of crude oils based on asphaltene stability. The predicted solubility parameter was fully compatible with the calculations from three empirical models that also correlate this property with other experimental data of crude oils.

Research paper thumbnail of Proposta De Calibração De Ampla Faixa Do Dma HPM Por Meio De Rotina Computacional

Blucher Chemical Engineering Proceedings

Research paper thumbnail of Asphaltene flocculation parameter in Brazilian crude oils and synthetic polar and nonpolar mixtures: Experimental and modeling

A critical solubility parameter for oils is proposed from Brazilian oils. Flory-Huggins model was... more A critical solubility parameter for oils is proposed from Brazilian oils. Flory-Huggins model was improved taking into account the electrostatic interactions. Solubility parameters are predicted successfully from asphaltene flocculation data. The asphaltene stabilizing species do not act in polar solvents. a b s t r a c t The experimental method used to predict solubility parameter of Brazilian crude oils takes into account the critical solubility parameter assumption. In this work, experimental ratifications to this assumption were found for both crude oils and nonpolar asphaltene mixtures. This is an important matter since the oil compatibility is estimated from this assumption. Models based on the Regular Solution and Flory-Huggins theories were used to estimate the solubility data of least-soluble asphaltenes. Thereby, it was observed that the employment of Kikic modification of the Flory-Huggins combinatorial term plus the replacement of the traditional Hildebrand solubility parameter by the Hansen solubility parameter in the energetic term greatly improved the performance of these models and led to the best correlation, even for polar and associative solvents. In addition, the impact of asphaltene blending on Brazilian oil stability was evaluated from two asphaltene fractions sequentially extracted. The results point out that the asphaltene subfractionation should be taken into account in the solubility modeling. From these results, a critical solubility parameter for Brazilian oils (16.8 MPa 1/2) is proposed to be used as a universal input parameter in the experimental methodology of predicting solubility parameter of crude oils based on asphaltene stability. The predicted solubility parameter was fully compatible with the calculations from three empirical models that also correlate this property with other experimental data of crude oils.

Research paper thumbnail of Solubility parameter of oils by several models and experimental oil compatibility data: implications for asphaltene stability

Petroleum Science and Technology, Apr 3, 2019

In a previous study we obtained reference values of solubility parameter of two Brazilian crude o... more In a previous study we obtained reference values of solubility parameter of two Brazilian crude oils based on asphaltene flocculation data. In this work, these reference values were compared to those obtained by nine models available in the literature and oil compatibility data were experimentally obtained to enhance the modeling evaluation. These evaluations allowed to select models to predict asphaltene stability and oil compatibility. As a result, only our method along with three other methods can accurately predict the experimental results of the compatibility between oil mixtures, and the conclusion is that usually recommended models are not the best choice.

Research paper thumbnail of Solubility parameter of narrow oil cuts by several models: quantifying the discrepancy among predictions for heavy cuts

Brazilian Journal of Chemical Engineering, Sep 30, 2021

In this study, the performance of nine models was evaluated in predicting the solubility paramete... more In this study, the performance of nine models was evaluated in predicting the solubility parameter of oil cuts. The oil cuts were generated from simulated distillation curves assuming a constant Watson factor. Five oils from different Brazilian geographic regions were used. It was observed that predictions diverge mainly for cuts having boiling points above 460 K. For instance, the maximum difference in the solubility parameter of the same cut can reach 9.8 MPa1/2 depending on the model used. For extrapolated results, this difference can reach 17.6 MPa1/2. The coherence of model extrapolations for heavier cuts was also evaluated. Furthermore, the volume additivity hypothesis of the solubility parameter was also assessed by comparing volume-averaged solubility parameters with the corresponding bulk solubility parameter of oils. In general, it was found that volumetric additivity is an acceptable simplification and, for the same oil, the maximum difference between the two ways of calculating the oil solubility parameter did not exceed 1.4 MPa1/2.

Research paper thumbnail of Prediction of speed of sound in compressed hydrocarbon and CO2 mixtures: theory comparison

Brazilian Journal of Chemical Engineering, Dec 20, 2022

Research paper thumbnail of Density of <i>n</i>-Heptane + <i>n</i>-Dodecane and Carbon Dioxide + <i>n</i>-Heptane + <i>n</i>-Dodecane Mixtures up to 70 MPa from (293.15 to 363.15) K

Journal of Chemical & Engineering Data, Feb 3, 2021

Density measurements of the n-heptane + n-dodecane binary mixture were performed with a vibrating... more Density measurements of the n-heptane + n-dodecane binary mixture were performed with a vibrating tube densitometer in the temperature range of (293.15 to 363.15) K and pressure up to 70 MPa at six...

Research paper thumbnail of Experimental and modeling studies of density and viscosity behavior of a live fluid due to CO2injection at reservoir condition

Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles

In this study, highly accurate measurements of density and dynamic viscosities of a recombined li... more In this study, highly accurate measurements of density and dynamic viscosities of a recombined live oil and its mixture with additional CO2were performed. The experiments were carried out under pressure and temperature gradients found in Brazilian Pre-salt reservoirs, that is, in the pressure range from (27.6 to 68.9) MPa and at (333.15 and 353.15) K. The assumption of volume change on mixing is evaluated from the experimental results, and the influence of pressure and temperature on the volume change upon mixing is assessed. The densities of mixtures are calculated considering (i) the excess volume approach, and (ii) no volume change. The densities are better correlated using the excess volume approach with Average Absolute Deviations (AAD) of 0.03%. Thirteen mixing rules of viscosity are examined by comparing the predicted values with the experimental viscosity of the recombined live oil + CO2mixture. The performance of some rules using compositional fractions (molar, volume and w...

Research paper thumbnail of Interfacial properties of asphaltene–brine systems and analysis of adsorption kinetics: effects of ion and water injection for EOR

Brazilian Journal of Chemical Engineering

Research paper thumbnail of Brazilian Pre Salt Oil CO2-RICH Unconcentional Phase Behavior: Experimental PVT and Modeling

Rio Oil and Gas Expo and Conference

Research paper thumbnail of Avaliação Da Metodologia De Determinação Do Inicio Da Precipitação Dos Asfaltenos Em Petróleos Utilizando FT-Nir

O ponto de inicio de precipitacao dos asfaltenos, IP, e definido como a quantidade minima do prec... more O ponto de inicio de precipitacao dos asfaltenos, IP, e definido como a quantidade minima do precipitante, em geral n-heptano, adicionado ao petroleo para que ocorra a precipitacao dos asfaltenos. E observado que este fenomeno esta associado a fatores cineticos inerentes ao sistema, fato ate entao nao mensurado adequadamente nas modelagens de comportamento dos asfaltenos. Neste contexto, a abundantemente usada tecnica de determinacao de inicio de precipitacao dos asfaltenos utilizando espectroscopia de NIR (near infrared) e investigada. Sao demonstradas quantidades significativas de informacoes adicionais acerca da utilizacao desta tecnica, como por exemplo, o efeito da taxa de adicao de n-heptano ao petroleo. Neste trabalho sao utilizadas duas amostras de petroleo denominadas P1 e P2, com distintas caracteristicas fisico-quimicas, onde se determina que os valores de IP variaram entre 2,59 3,25 e 0,56 1,2 ml de heptano/g de petroleo, respectivamente, a depender da vazao utilizada. A...

Research paper thumbnail of Solubility Parameter from an Acoustic Method: Temperature Effect and Applications to Petroleum

Chemical Engineering & Technology, 2020

Research paper thumbnail of Asphaltene flocculation parameter in Brazilian crude oils and synthetic polar and nonpolar mixtures: Experimental and modeling

Fuel, 2017

Abstract The experimental method used to predict solubility parameter of Brazilian crude oils tak... more Abstract The experimental method used to predict solubility parameter of Brazilian crude oils takes into account the critical solubility parameter assumption. In this work, experimental ratifications to this assumption were found for both crude oils and nonpolar asphaltene mixtures. This is an important matter since the oil compatibility is estimated from this assumption. Models based on the Regular Solution and Flory-Huggins theories were used to estimate the solubility data of least-soluble asphaltenes. Thereby, it was observed that the employment of Kikic modification of the Flory-Huggins combinatorial term plus the replacement of the traditional Hildebrand solubility parameter by the Hansen solubility parameter in the energetic term greatly improved the performance of these models and led to the best correlation, even for polar and associative solvents. In addition, the impact of asphaltene blending on Brazilian oil stability was evaluated from two asphaltene fractions sequentially extracted. The results point out that the asphaltene subfractionation should be taken into account in the solubility modeling. From these results, a critical solubility parameter for Brazilian oils (16.8 MPa 1/2 ) is proposed to be used as a universal input parameter in the experimental methodology of predicting solubility parameter of crude oils based on asphaltene stability. The predicted solubility parameter was fully compatible with the calculations from three empirical models that also correlate this property with other experimental data of crude oils.

Research paper thumbnail of Proposta De Calibração De Ampla Faixa Do Dma HPM Por Meio De Rotina Computacional

Blucher Chemical Engineering Proceedings

Research paper thumbnail of Asphaltene flocculation parameter in Brazilian crude oils and synthetic polar and nonpolar mixtures: Experimental and modeling

A critical solubility parameter for oils is proposed from Brazilian oils. Flory-Huggins model was... more A critical solubility parameter for oils is proposed from Brazilian oils. Flory-Huggins model was improved taking into account the electrostatic interactions. Solubility parameters are predicted successfully from asphaltene flocculation data. The asphaltene stabilizing species do not act in polar solvents. a b s t r a c t The experimental method used to predict solubility parameter of Brazilian crude oils takes into account the critical solubility parameter assumption. In this work, experimental ratifications to this assumption were found for both crude oils and nonpolar asphaltene mixtures. This is an important matter since the oil compatibility is estimated from this assumption. Models based on the Regular Solution and Flory-Huggins theories were used to estimate the solubility data of least-soluble asphaltenes. Thereby, it was observed that the employment of Kikic modification of the Flory-Huggins combinatorial term plus the replacement of the traditional Hildebrand solubility parameter by the Hansen solubility parameter in the energetic term greatly improved the performance of these models and led to the best correlation, even for polar and associative solvents. In addition, the impact of asphaltene blending on Brazilian oil stability was evaluated from two asphaltene fractions sequentially extracted. The results point out that the asphaltene subfractionation should be taken into account in the solubility modeling. From these results, a critical solubility parameter for Brazilian oils (16.8 MPa 1/2) is proposed to be used as a universal input parameter in the experimental methodology of predicting solubility parameter of crude oils based on asphaltene stability. The predicted solubility parameter was fully compatible with the calculations from three empirical models that also correlate this property with other experimental data of crude oils.