Modelling of phase equilibria in CH4–C2H6–C3H8–nC4H10–NaCl–H2O systems

Li, J.; Zhang, Zhigang; Luo, Xiaorong; Li, Xiaochun

doi:10.1016/j.apgeochem.2015.02.006

Cited by 14 publications

(8 citation statements)

References 95 publications

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“…where i denotes a component (i = H 2 O, CO 2 , N 2 , and O 2 ). For H 2 O, the equation from previous work [3,4] is used,…”

Section: Equilibrium Constantmentioning

confidence: 99%

“…According to an International Energy Agency Greenhouse Gas R&D Programme (IEAGHG) report [2], even though there are various impurities obtained from CO 2 capture techniques, the main impurities are nitrogen (N 2 ) and oxygen (O 2 ). When CO 2 is injected with impurities, fluid properties such as gas density, viscosity and gas-water-mineral interactions could be different [3,4] compared to the injection of pure CO 2 . The presence of impurities decreases CO 2 solubility in brine and also affects H 2 O contents in non-aqueous phase.…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic Modeling of CO2-N2-O2-Brine-Carbonates in Conditions from Surface to High Temperature and Pressure

Ahmed²,

2018

Energies

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Nitrogen (N 2 ) and oxygen (O 2 ) are important impurities obtained from carbon dioxide (CO 2 ) capture procedures. Thermodynamic modeling of CO 2 -N 2 -O 2 -brine-minerals is important work for understanding the geochemical change of CO 2 geologic storage with impurities. In this work, a thermodynamic model of the CO 2 -N 2 -O 2 -brine-carbonate system is established using the "fugacity-activity" method, i.e., gas fugacity coefficients are calculated using a cubic model and activity coefficients are calculated using the Pitzer model. The model can calculate the properties at an equilibrium state of the CO 2 -N 2 -O 2 -brine-carbonate system in terms of gas solubilities, mineral solubilities, H 2 O solubility in gas-rich phase, species concentrations in each phase, pH and alkalinity. The experimental data of this system can be well reproduced by the presented model, as validated by careful comparisons in conditions from surface to high temperature and pressure. The model established in this work is suitable for CO 2 geologic storage simulation with N 2 or O 2 present as impurities.Thermodynamic modeling of CO 2 -impurities-brine systems is essential work for understanding subsurface fluid transport. It mainly consists of the modeling of phase partitioning, density and viscosity. Soreide and Whitson [7] constructed mutual solubility of multi-gases (including CO 2 , CH 4 , H 2 S and N 2 ) and brine systems. The model shows good accuracy at low temperature and pressure with a salinity less than 2 (molal). Li et al. [3] made modifications and achieved good accuracy at wider ranges of temperature, pressure and salinity for CO 2 -CH 4 -H 2 S-brine systems. Gas solubility modeling of CO 2 , N 2 and O 2 in water and brine has been performed by Duan and Sun [8], Mao and Duan [9] and Geng and Duan [10] based on comprehensive reviews of experimental data. These models can reproduce most of the experimental data over wide ranges of temperature, pressure and salinity. However, they can only consider single gas component cases, and cannot calculate multi-gas and brine system equilibria. Tan et al.[11] developed a model for CO 2 , SO 2 and brine system equilibria using a "cubic plus association" (CPA) method. Sun and co-workers developed an improved "Statistical Associating Fluid Theory" (SAFT) model for CO 2 -brine and water-hydrocarbon systems by introducing a Lennard-Jones (LJ) term (SAFT-LJ models, [12][13][14]). CPA and SAFT type models usually have high computation accuracy, but are time-consuming and are not practical for reservoir simulation implementations.Carbonates (including calcite, magnesite and dolomite) are important minerals for CO 2 geologic storage.When CO 2 is injected into porous media with carbonate minerals, dissolution of carbonates into aqueous phase is enhanced. Water property (such as pH, ion concentration, density and viscosity), porosity and permeability are affected consequently. Thermodynamic modeling work for CO 2 -brine-mineral systems began in the 1980s. Harvie and Weare [15] and Harvie et al. ...

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“…where i denotes a component (i = H 2 O, CO 2 , N 2 , and O 2 ). For H 2 O, the equation from previous work [3,4] is used,…”

Section: Equilibrium Constantmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermodynamic Modeling of CO2-N2-O2-Brine-Carbonates in Conditions from Surface to High Temperature and Pressure

Ahmed²,

2018

Energies

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“…where NA(0) ( ) stands for standard chemical potential of component , which is the ideal gas chemical potential at the pressure of 1 bar [6,7]; is mole fraction of component in nonaqueous phase; is fugacity and is fugacity coefficient; is the gas constant (8.31446 J/K/mol); is temperature in K; and is pressure in bar hereafter.…”

Section: Co 2 -Ch 4 -Brine Mutual Solubility Modelingmentioning

confidence: 99%

“…For equilibrium constant of H 2 O, we follow the work of Li et al [7] with an empirical equation revised from Spycher et al (2003):…”

Section: Equilibrium Constantsmentioning

confidence: 99%

A Geochemical Model of Fluids and Mineral Interactions for Deep Hydrocarbon Reservoirs

Ahmed²,

Zhang

et al. 2017

Geofluids

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A mutual solubility model for CO 2 -CH 4 -brine systems is constructed in this work as a fundamental research for applications of deep hydrocarbon exploration and production. The model is validated to be accurate for wide ranges of temperature (0-250 ∘ C), pressure (1-1500 bar), and salinity (NaCl molality from 0 to more than 6 mole/KgW). Combining this model with PHREEQC functionalities, CO 2 -CH 4 -brine-carbonate-sulfate equilibrium is calculated. From the calculations, we conclude that, for CO 2 -CH 4 -brine-carbonate systems, at deeper positions, magnesium is more likely to be dissolved in aqueous phase and calcite can be more stable than dolomite and, for CO 2 -CH 4 -brine-sulfate systems, with a presence of CH 4 , sulfate ions are likely to be reduced to S 2− and H 2 S in gas phase could be released after S 2− saturated in the solution. The hydrocarbon "souring" process could be reproduced from geochemical calculations in this work.

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“…Li and Firoozabadi 27 described the cross association between non-water components and water in the framework of perturbation theory. Li 28 noted that SAFT and CPA models usually exhibit good performance for standalone calculations, but they are not timeefficient when used for numerical simulations. Another approach for equilibrium calculations for thermal compositional simulation is based on equations of state.…”

Section: ■ Introductionmentioning

confidence: 99%

Three-Phase Equilibrium Calculations of Water/Hydrocarbon/Nonhydrocarbon Systems Based on the Equation of State (EOS) in Thermal Processes

Huang

et al. 2021

ACS Omega

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A simple and novel approach is proposed to represent the mutual solubility of water and hydrocarbon components based on equations of state at high temperatures in thermal recovery processes. Sϕreide and Whitson modifications are applied to the Peng–Robinson (PR) equation of state (EOS) so that all components, including the water component, can exist in all phases, reasonably representing gas solubility in water and water solubility in hydrocarbon phases. We propose an algorithm to assign binary interaction parameters (BIPs) for aqueous and nonaqueous phases. The water vapor pressure helps select initial K -values for stability analysis so that the aqueous phase can be split out first if present. The algorithm is tested by a wide range of variations in pressure, temperature, and composition. The results show the robustness of the algorithm and the effects of temperature and overall water mole fraction on phase behaviors in steam flooding processes.

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Modelling of phase equilibria in CH4–C2H6–C3H8–nC4H10–NaCl–H2O systems

Cited by 14 publications

References 95 publications

Thermodynamic Modeling of CO2-N2-O2-Brine-Carbonates in Conditions from Surface to High Temperature and Pressure

Thermodynamic Modeling of CO2-N2-O2-Brine-Carbonates in Conditions from Surface to High Temperature and Pressure

A Geochemical Model of Fluids and Mineral Interactions for Deep Hydrocarbon Reservoirs

Three-Phase Equilibrium Calculations of Water/Hydrocarbon/Nonhydrocarbon Systems Based on the Equation of State (EOS) in Thermal Processes

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