Coalbed Methane Modelling Best Practices

Philpot, Jared Anthony; Mazumder, Saikat; Naicker, Siddharta; Chang, Gladys; Boostani, Mohammad; Tovar, Miguel Ángel Aparicio; Vp, Sharma

doi:10.2523/17137-ms

Cited by 11 publications

(2 citation statements)

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“…Analytical and semi-analytical models, while offering advantages in terms of computational efficiency, often rely on simplifying assumptions to facilitate solutions [3,14,18]. In comparison with analytical models, numerical models can readily incorporate newly emerging mechanisms [19][20][21][22]. A common simplification involves neglecting the quadratic pressure gradient term.…”

Section: Introductionmentioning

confidence: 99%

Transient Pressure Behavior of CBM Wells during the Injection Fall-Off Test Considering the Quadratic Pressure Gradient

Gu,

Wu,

Sun

2024

Nanomaterials

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Conventional coalbed methane (CBM) reservoir models for injection fall-off testing often disregard the quadratic pressure gradient’s impact. This omission leads to discrepancies in simulating the transient behavior of formation fluids and extracting critical reservoir properties. Accurate determination of permeability, storability, and other properties is crucial for effective reservoir characterization and production forecasting. Inaccurate estimations can lead to suboptimal well placement, ineffective production strategies, and ultimately, missed economic opportunities. To address this shortcoming, we present a novel analytical model that explicitly incorporates the complexities of the quadratic pressure gradient and dual-permeability flow mechanisms, prevalent in many CBM formations where nanopores are rich, presenting a kind of natural nanomaterial. This model offers significant advantages over traditional approaches. By leveraging variable substitution, it facilitates the derivation of analytical solutions in the Laplace domain, subsequently converted to real-space solutions for practical application. These solutions empower reservoir engineers to generate novel type curves, a valuable tool for analyzing wellbore pressure responses during injection fall-off tests. By identifying distinct flow regimes within the reservoir based on these type curves, engineers gain valuable insights into the dynamic behavior of formation fluids. This model goes beyond traditional approaches by investigating the influence of the quadratic pressure gradient coefficient, inter-porosity flow coefficient, and storability ratio on the pressure response. A quantitative comparison with traditional models further elucidates the key discrepancies caused by neglecting the quadratic pressure gradient. The results demonstrate the proposed model’s ability to accurately depict the non-linear flow behavior observed in CBM wells. This translates to more reliable pressure and pressure derivative curves that account for the impact of the quadratic pressure gradient.

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Section: Introductionmentioning

confidence: 99%

Transient Pressure Behavior of CBM Wells during the Injection Fall-Off Test Considering the Quadratic Pressure Gradient

Gu,

Wu,

Sun

2024

Nanomaterials

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“…Meng et al (2018) established a multi-factor coupled mathematical model for the dynamic change of coal reservoir permeability by considering the effects of stress sensitivity, matrix shrinkage effect, and slip effect. Sun et al (2018) developed a multi-factor coupled gas-water phase effective permeability model for CBM production process based on the P-M model and the Kerry relative permeability model, which quantified the effective permeability of the gas/water phase as a function of pressure and saturation. Peng et al (2019) studied in detail the effect of coal dust on the early drainage and development permeability of coalbed methane reservoirs, and established a mathematical model of the four phases of gas-water-fluidsolid-static describing the fluid transport pattern in coal seams, which was solved using finite-difference equations.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of coalbed methane under the mining conditions based on dynamic virtual well and variable permeability field

Zhang

Wang

Zhang

et al. 2022

Energy Exploration & Exploitation

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After coal seam mining,stress change and rock movement in adjacent rock strata, make permeability and other fields change in adjacent coal seam. At the same time, due to the exploitation of coal seams, material exchange may occur in the adjacent coal seams. It also caused desorption of near coal seam near the mining working face. Recent years, with the development of coalbed methane mining technology under pressure relief in mining areas, it is necessary to carry out numerical simulation under coalbed methane mining conditions to realize the optimization of coalbed methane extraction simulation under mining conditions. The coupling effect of dynamic virtual well and variable permeability field advancing with the mining face is used to simulate the output of coalbed methane under mining conditions: the dynamic virtual well is used to advance with the mining face to characterize the influence of the working face on the material exchange of adjacent coal seams in the mining process; the use of variable permeability field to realize the influence of the permeability of the adjacent coal seam during the advancement of the working face. Finally, through the dynamic coupling of variable permeability field and dynamic virtual well with the mining face, the rapid pressure relief effect of high speed and short time on the adjacent layer under the influence of mining is characterized. The simulation results of the computer simulation software written by the algorithm show that when the mining effect is not considered, that is, when the algorithm does not consider the dynamic virtual well production and the variable permeability field, it is basically consistent with the commercial software simulation results, but for the consideration of mining condition is a situation that commercial software cannot simulate, and the simulation results of this algorithm are more consistent with the actual monitoring data of the mine. This method achieves numerical simulation of CBM under mining conditions by improving the mature algorithm, which can provide effective guidance for future CBM capacity prediction under mining conditions.

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Geological Influential Factors on the SIS Well Productivity in Teviot-Brook Block, Moranbah Gas Field

Bie

Zhang

et al. 2020

Springer Series in Geomechanics and Geoengineering

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Coalbed Methane Modelling Best Practices

Cited by 11 publications

References 0 publications

Transient Pressure Behavior of CBM Wells during the Injection Fall-Off Test Considering the Quadratic Pressure Gradient

Transient Pressure Behavior of CBM Wells during the Injection Fall-Off Test Considering the Quadratic Pressure Gradient

Numerical simulation of coalbed methane under the mining conditions based on dynamic virtual well and variable permeability field

Geological Influential Factors on the SIS Well Productivity in Teviot-Brook Block, Moranbah Gas Field

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