A bidisperse pore diffusion model for methane displacement desorption in coal by CO2 injection☆

Shi, Ji‐Quan; Durucan, Şevket

doi:10.1016/s0016-2361(03)00010-3

Cited by 244 publications

(139 citation statements)

References 15 publications

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“…To interpret and quantify the observed gas uptake rates in coal two models have been used: unipore model, based on the solution to Fick's second law for spherical symmetric flow [18][19][20][21][22] and bidisperse sorption/diffusion gas transport model for coals characterized by two distinct pore systems [18,20,[23][24][25][26][27][28]. It is generally confirmed that the amount micropores increase and mesopores decrease with coal rank.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of methane and carbon dioxide sorption and sorption–induced expansion of coal – kinetic equations assessment

et al. 2016

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Abstract. The aim of this study was to investigate the ability of kinetic equations to describe the sorption kinetics and expansion rate of solid coal samples. In order to address his issue the sorption kinetics of methane and carbon dioxide on bituminous coals were studied. At the same time, the changes occurring in the sample's overall dimensions, which accompanied sorption processes, were monitored. Experiments were carried out at high pressure by means of the volumetric method on a cubicoid solid samples. Several literature-based modeling approaches and equations are proposed to fit the kinetic curves of gas deposition, as well as the adequate kinetics of coal swelling. First equation represents the traditional approach to interpret experimental data in terms of fast and slow sorption process and consider the combination of two first-order rate functions. The other empirical kinetic equations are: the pseudo-second-order kinetic equation (PSOE), Elovich equation and the stretched exponential equation (SE). Two of the four equations are suitable to describe the kinetics of methane and carbon dioxide sorption and have been successfully used to quantify the observed dilatometric phenomena rates. The stretched exponential equation gave the best fit to the experimental data.

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Section: Introductionmentioning

confidence: 99%

Kinetics of methane and carbon dioxide sorption and sorption–induced expansion of coal – kinetic equations assessment

et al. 2016

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“…Gas in coal cleat system is stored in free and absorbed states and gas circulation is accomplished through the laminar process. In the last one, and taking into account the gas concentration and the location, gas circulates into a specific direction depending on the pressure gradient and on the fluid properties (Kolesar and Ertekin, 1986;Shi and Durucan, 2003). In contrast, the gas stored in coal pores is in the adsorbed state and diffusion is the dominant gas circulation process.…”

Section: Introductionmentioning

confidence: 99%

“…In the diffusion process, the gas flow depends on three main related parameters: (1) the pressure variation effect, which induces distinct behaviours in the different components present on the gas mixture; (2) the interactions that these gas components establish with the coal porous structure, and, consequently; (3) the coal porous structure shrinking and swelling effects. Several models have been and are being used to describe gas circulation in coal seams, such as those presented by Brouers et al (2005), Cui et al (2004 b), Mavor et al (1990), Mehrer (2007), Pruess (2006), Ruckenstein et al (1971), Saghafi et al (2007), and Shi and Durucan (2003). In fact, two different models are being adopted to study the gas circulation in coal seams: one is the unipore diffusion model (Crank, 1975), which is mainly concerned in studying the gas circulation in coal porous structure, i.e.…”

Section: Introductionmentioning

confidence: 99%

Gas content derivative data versus diffusion coefficient

Rodrigues

Dinis

Sousa

2016

Energy Exploration & Exploitation

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The study of the gas diffusion process has a main role in both coalbed methane (CBM) production and CO 2 injection in geological sequestration projects. The accurate determination of gas diffusion coefficients in unconventional reservoirs such as coal seams requires a consistent mathematical approach. The study of the gas diffusion process in coal seams was carried out using sorption isotherms. The Langmuir model for individual gases and the extended Langmuir model for multicomponent gas mixtures were applied to fit sorption isotherm data. ''Gas content derivative data'' and ''gas content changes'' emerged as crucial mathematical parameters to accurately study the gas diffusion process. The main goal of this paper is to define the degree of interaction between the gas content derivative data and the gas diffusion process. Experiments were performed on three samples selected from two different coals, which were submitted to three different gas compositions, viz 99.999% CH 4 ; 99.999% CO 2 ; and a gas mixture containing 74.99% CH 4 + 19.99% CO 2 + 5.02% N 2 , at 35 C, and at pressures ranging from 0 up to 50 bar. Experimental results obtained from the three samples indicate that during adsorption/desorption processes, the diffusion coefficients increase and the gas content changes decrease when the pressure decreases, due to the sample saturation degrees and to the kinetic mechanisms increase. Additionally, the ''gas content derivative data'' scattering is slightly lower during the desorption process than during the adsorption process. These behaviours are clearly identified when using methane, but are even more evident when using CO 2 and the gas mixture, due to the CO 2 interaction with coal porous structure, which induces a considerable resistance to CO 2 release. The results show that sample B (CH 4 + CO 2 + N 2 ) displays higher diffusion coefficient values (this behaviour is mainly related to the presence of N 2 ) than sample C (CH 4 ) and than sample A (CO 2 ).

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“…A variety of models have been developed to describe gas diffusion between matrix and cleats, which include the equilibrium model with instantaneous diffusion, non-equilibrium model with pseudo-steady-state or unsteady-state diffusion governed by Fick's Law [11], and the bidisperse diffusion model [12]. Flow through the natural fractures can typically be represented by dual-porosity single-permeability model (without the presence of large-scale fractures) or triple-porosity dual-permeability model.…”

Section: Introductionmentioning

confidence: 99%

Discrete Fracture Modeling of 3D Heterogeneous Enhanced Coalbed Methane Recovery with Prismatic Meshing

Zhang

Gong

et al. 2015

Energies

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Abstract:In this study, a 3D multicomponent multiphase simulator with a new fracture characterization technique is developed to simulate the enhanced recovery of coalbed methane. In this new model, the diffusion source from the matrix is calculated using the traditional dual-continuum approach, while in the Darcy flow scale, the Discrete Fracture Model (DFM) is introduced to explicitly represent the flow interaction between cleats and large-scale fractures. For this purpose, a general formulation is proposed to model the multicomponent multiphase flow through the fractured coal media. The S&D model and a revised P&M model are incorporated to represent the geomechanical effects. Then a finite volume based discretization and solution strategies are constructed to solve the general ECBM equations. The prismatic meshing algorism is used to construct the grids for 3D reservoirs with complex fracture geometry. The simulator is validated with a benchmark case in which the results show close agreement with GEM. Finally, simulation of a synthetic heterogeneous 3D coal reservoir modified from a published literature is performed to evaluate the production performance and the effects of injected gas composition, well pattern and gas buoyancy.

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A bidisperse pore diffusion model for methane displacement desorption in coal by CO2 injection☆

Cited by 244 publications

References 15 publications

Kinetics of methane and carbon dioxide sorption and sorption–induced expansion of coal – kinetic equations assessment

Kinetics of methane and carbon dioxide sorption and sorption–induced expansion of coal – kinetic equations assessment

Gas content derivative data versus diffusion coefficient

Discrete Fracture Modeling of 3D Heterogeneous Enhanced Coalbed Methane Recovery with Prismatic Meshing

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