A Fully Coupled Multiphase Multicomponent Flow and Geomechanics Model for Enhanced Coalbed-Methane Recovery and CO2 Storage
TL;DR: In this paper, a fully coupled multiphase multicomponent flow and geomechanics model is developed for coalbed-methane (CBM) recovery by the injection of CO2 and/or N2.
Abstract: Enhanced coalbed-methane (ECBM) recovery by the injection of CO2 and/or N2 is an attractive method for recovering additional natural gas resources, while at the same time sequestering CO2 in the subsurface. For the naturally fractured coalbed-methane (CBM) reservoirs, the coupled fluid-flow and geomechanics effects involving both the effective-stress effect and the matrix shrinkage/swelling, are crucial to simulate the permeability change and; thus gas migration during primary or enhanced CBM recovery. In this work, a fully coupled multiphase multicomponent flow and geomechanics model is developed. The coupling effects are modeled by introducing a set of elaborate geomechanical equations, which can provide more fundamental understanding about the solid deformation and give a more accurate permeability/ porosity prediction over the existing analytical models. In addition, the fluid-flow model in our study is fully compositional; considering both multicomponent gas dissolution and water volatility. To obtain accurate gas solubility in the aqueous phase, the PengRobinson equation of state (EOS) is modified according to the suggestions of Soreide and Whitson (1992). An extended Langmuir isotherm is used to describe the adsorption/desorption behavior of the multicomponent gas to/from the coal surface. With a fully implicit finite-difference method, we develop: a 3D, multiphase, multicomponent, dual-porosity CBM/ECBM research code that is fully compositional and has fully coupled fluid flow and geomechanics. It has been partially validated and verified by comparison against other simulators such as GEM, Eclipse, and Coalgas. We then perform a series of simulations/investigations with our research code. First, history matching of Alberta flue-gas-injection micropilot data is performed to test the permeability model. The commonly used uniaxial-strain and constant-overburden-stress assumptions for analytical permeability models are then assessed. Finally, the coupling effects of fluid flow and geomechanics are investigated, and the impact of different mixed CO2/N2 injection scenarios is explored for both methane (CH4) production and CO2 sequestration.
Citations
More filters
12 Apr 2014
79 citations
TL;DR: In this article, a fully coupled two-phase flow, transport, and poromechanics numerical model for the analysis of geomechanical impacts on coalbed methane (CBM) production is presented.
67 citations
Additional excerpts
...The permeability of coal is sensitive to stress changes and deformation (Clarkson et al., 2013; Wei and Zhang, 2013)....
[...]
TL;DR: The UNConventional Oil and Gas simulator (UNCONG) as discussed by the authors is based on the black oil model and the compositional model, and it can handle unconventional oil and gas problems more properly.
49 citations
TL;DR: In this paper, Monte Carlo simulations have been carried out to generate new simulated data of hydrogen solubility in aqueous NaCl solutions in temperature and salinity ranges of interest for geological applications, and for which no experimental data are currently available.
Abstract: Hydrogen is targeted to have a significant influence on the energy mix in the upcoming years. Its underground injection is an efficient solution for large-scale and long-term storage. Furthermore, natural hydrogen emissions have been proven in several locations of the world, and the potential underground accumulations constitute exciting carbon-free energy sources. In this context, comprehensive models are necessary to better constrain hydrogen behavior in geological formations. In particular, solubility in brines is a key-parameter, as it directly impacts hydrogen reactivity and migration in porous media. In this work, Monte Carlo simulations have been carried out to generate new simulated data of hydrogen solubility in aqueous NaCl solutions in temperature and salinity ranges of interest for geological applications, and for which no experimental data are currently available. For these simulations, molecular models have been selected for hydrogen, water and Na+ and Cl− to reproduce phase properties of pure components and brine densities. To model solvent-solutes and solutes-solutes interactions, it was shown that the Lorentz-Berthelot mixing rules with a constant interaction binary parameter are the most appropriate to reproduce the experimental hydrogen Henry constants in salted water. With this force field, simulation results match measured solubilities with an average deviation of 6%. Additionally, simulation reproduced the expected behaviors of the H2 O + H2 + NaCl system, such as the salting-out effect, a minimum hydrogen solubility close to 57 °C, and a decrease of the Henry constant with increasing temperature. The force field was then used in extrapolation to determine hydrogen Henry constants for temperatures up to 300 °C and salinities up to 2 mol/kgH2O . Using the experimental measures and these new simulated data generated by molecular simulation, a binary interaction parameter of the Soreide and Whiston equation of state has been fitted. The obtained model allows fast and reliable phase equilibrium calculations, and it was applied to illustrative cases relevant for hydrogen geological storage or H2 natural emissions.
31 citations
References
More filters
TL;DR: In this paper, a simple technique is described for calculating the adsorption equilibria for components in a gaseous mixture, using only data for the pure-component adaption equilibrium at the same temperature and on the same adsorbent.
Abstract: A simple technique is described for calculating the adsorption equilibria for components in a gaseous mixture, using only data for the pure-component adsorption equilibria at the same temperature and on the same adsorbent. The proposed technique is based on the concept of an ideal adsorbed solution and, using classical surface thermodynamics, an expression analogous to Raoult's law is obtained. The essential idea of the calculation lies in the recognition that in an ideal solution the partial pressure of an adsorbed component is given by the product of its mole fraction in the adsorbed phase and the pressure which it would exert as a pure adsorbed component at the same temperature and spreading pressure as those of the mixture. Predicted isotherms give excellent agreement with experimental data for methane-ethane and ethylene-carbon dioxide on activated carbon and for carbon monoxide-oxygen and propane-propylene on silica gel. The simplicity of the calculation, which requires no data for the mixture, makes it especially useful for engineering applications.
3,098 citations
"A Fully Coupled Multiphase Multicom..." refers methods in this paper
...Several models have been proposed to describe the former behavior, such as the extended Langmuir model (Yang 1987), the ideal-adsorbed-solution model (Myers and Prausnitz 1965; Clarkson and Bustin 2000), and the 2D EOS model (Zhou et al....
[...]
Book•
01 Apr 1987
TL;DR: In this article, the authors present an analysis of gas mixtures rate processes in adsorbers adsorber dynamics, bed profiles and breakthrough curves cyclic gas separation processes and pressure-swing adsorption.
Abstract: Adsorbents and adsorption isotherms equilibrium adsorption of gas mixtures rate processes in adsorbers adsorber dynamics - bed profiles and breakthrough curves cyclic gas separation processes pressure-swing adsorption - principles and processes pressure-swing adsorption - models and experiments.
1,814 citations
"A Fully Coupled Multiphase Multicom..." refers methods in this paper
...Several models have been proposed to describe the former behavior, such as the extended Langmuir model (Yang 1987), the ideal-adsorbed-solution model (Myers and Prausnitz 1965; Clarkson and Bustin 2000), and the 2D EOS model (Zhou et al....
[...]
TL;DR: In this article, a new theoretical model for calculating pore volume compressibility and permeability in coals as a function of effective stress and matrix shrinkage, using a single equation is presented.
Abstract: In naturally fractured formations, such as coal, permeability is sensitive to changes in stress or pore pressure (i.e., effective stress). This paper presents a new theoretical model for calculating pore volume compressibility and permeability in coals as a function of effective stress and matrix shrinkage, using a single equation. The equation is appropriate for uniaxial strain conditions, as expected in a reservoir. The model predicts how permeability changes as pressure is decreased (i.e., drawdown). Pore volume compressibility is derived in this theory from fundamental reservoir parameters. It is not constant, as often assumed. Pore volume compressibility is high in coals because porosity is so small. A rebound in permeability can occur at lower drawdown pressures for the highest modulus and matrix shrinkage values. We have also history matched rates from a {open_quotes}boomer{close_quotes} well in the fairway of the San Juan basin using various stress-dependent permeability functions. The best fit stress-permeability function is then compared with the new theory.
682 citations
"A Fully Coupled Multiphase Multicom..." refers background or methods in this paper
...To model the effects of effective stress and matrix shrinkage/swelling, GEM, Eclipse, and Coalgas use different analytical permeability/ porosity formulations: GEM and Eclipse adopt the P&M model (Palmer and Mansoori 1998), and Coalgas uses the ARI model (Sawyer et al....
[...]
...Besides, there is field evidence indicating a strong rebound in permeability during CBM recovery (Mavor and Vaughn 1998; Palmer and Mansoori 1998), which cannot be captured by the Gray model....
[...]
...Given uniaxial-strain and constant-overburden-stress conditions, assuming Langmuir-like matrix shrinkage to be analogous to thermal expansion (Palmer and Mansoori 1998; Shi and Durucan 2004; Cui and Bustin 2005), considering the coal grain compressibility, based on a stress/strain constitutive relation for the isotropic linear poroelastic medium, Palmer and Mansoori (1998) derived the equation for porosity change and; thus the original P&M permeability model....
[...]
...By considering that coal can be idealized as a bundled matchstick geometry, the cubic permeability/porosity relationship can be used (Palmer and Mansoori 1998):...
[...]
...This model has been widely used to match the laboratory permeability test data and field production data (Mavor and Vaughn 1998; Palmer and Mansoori 1998)....
[...]
TL;DR: In this article, the first two papers concerning the movement of gas in coal seams were published, and they dealt directly with the physical behavior of the coal seam as a reservoir, and showed that coal seams show considerable differences in behavior from normal porous gas reservoirs in both the mode of gas storage and permeability characteristics.
Abstract: This is the first of two papers concerning the movement of gas in coal seams. It deals directly with the physical behavior of the coal seam as a reservoir. Coal seams show considerable differences in behavior from normal porous gas reservoirs in both the mode of gas storage and permeability characteristics. Most of the storage of gas in coal is by sorption into the coal structure, while the coal permeability is cleat-(fracture-) or joint-controlled and may vary over a wide range during production. This permeability fluctuation is not solely a phase relative permeability effect, but is rather a result of the opposing effects of effective stress increase with fluid pressure reduction and shrinkage of the coal. Reducing fluid pressure tends to close the cleats, reducing permeability, while shrinkage tends to open them.
614 citations
TL;DR: A review of coal permeability and the approaches to modelling its behavior can be found in this paper, where the authors identify some potential areas for future work, as well as some potential directions for future research.
613 citations