Experimental study on damage and the permeability evolution process of methane-containing coal under different temperature conditions

Li, Bobo; Ren, Cheng; Wang, Zhihe; Li, Jianhua; Yang, Kailun; Xu, Jiang

doi:10.1016/j.petrol.2019.106509

Cited by 42 publications

(18 citation statements)

References 55 publications

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“…The physical effect can be attributed to adsorption swelling and thermal swelling during CO 2 or CH 4 injection under high-temperature conditions, and the internal deformation in this process affects the structure of coal and promotes a permeability decrease with increasing temperature. When the experimental temperature exceeds 100 °C, chemical reactions (decomposition or volatilization of coal components) appear, 53 causing deterioration and damage of the coal body. Additionally, gas slippage is also present in high-temperature environments.…”

Section: Resultsmentioning

confidence: 99%

Investigation of the CO₂ Flooding Behavior and Its Collaborative Controlling Factors

Cao

Wang

Liang³

et al. 2020

Energy Fuels

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CO2 injection to enhance coalbed methane (CO2-ECBM) production is a promising technology for realizing the efficient exploitation of new energy resource, but its effect is cooperatively affected by miscellaneous influencing factors. To elucidate the mechanism and increase the efficiency of the displacement of CH4 by CO2, CO2 flooding experiments under the influence of the injection pressure, confining pressure, and temperature were conducted. The results show that an increase in the injection pressure enlarges the pore-fracture network of the coal matrix and promotes its gas adsorption ability and seepage capacity, while an increase in the confining pressure compresses the coal body and reduces the adsorption capacity and permeability. Increasing the temperature enhances kinetic energy and induces the thermal swelling effect, which disfavors the adsorption and seepage processes. The CO2 adsorption capacity is larger than the CH4 adsorption capacity due to the higher adsorption affinity of CO2, but the CO2 permeability is lower than the CH4 permeability due to the severe adsorption swelling effect. The CO2 flooding process is characterized by three parameters (equal percentage displacement time, displacement rate, and displacement efficiency) and can be divided into the CO2 driving stage, replacement and displacement stage, and equilibrium stage. The injection pressure and temperature decrease the displacement time and increase the displacement rate and displacement efficiency, while confining pressure shows the opposite trends. Multifactor interaction models of the displacement efficiency of coal seams at various buried depths were established and demonstrated to appropriately predict the displacement efficiency of CO2-ECBM in deep coal seams. The displacement efficiency is controlled by the reservoir performance, geological characteristics, and CO2 injection technology. The selection of a high-permeability coal reservoir and coal seams with an appropriate buried depth and the development of a reasonable injection plan are suggested for the implementation of CO2-ECBM extraction.

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Section: Resultsmentioning

confidence: 99%

Investigation of the CO₂ Flooding Behavior and Its Collaborative Controlling Factors

Cao

Wang

Liang³

et al. 2020

Energy Fuels

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“…The permeability of gasbearing coal increases exponentially with the development of damage. Li et al [39] comprehensively discussed the effective stress of coal-rock mass under the action of external load and established a statistical constitutive model of elastoplastic damage. Based on the variable amplitude loading, Liu [40] derived the variation law of fatigue damage variable and deduced and established the constitutive model.…”

Section: Geofluidsmentioning

confidence: 99%

Study on the Damage Model of Coal Rock Caused by Hydraulic Pressure and Electrical Impulse in Borehole

et al. 2021

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The purpose of this study is to study the damage and fracturing effects of high-voltage discharge on coal-rock mass under the action of hydrostatic pressure. Based on the traditional damage evolution model and the change of the effective bearing area and stress around the microcrack of coal-rock mass on a microscopic scale, the expression of macroscopic damage variation of coal-rock mass under the action of electrohydraulic coupling was derived, and its damage constitutive relation was established. The high-voltage pulse water shock stress test of coal-rock mass under the conditions of different water pressures and voltages was carried out, and its damage numerical model was established by the ABAQUS/XFEM. The damage variable values of coal-rock mass with different electrohydraulic parameters were compared to characterize the generation and expansion of internal macroscopic cracks. From the results, it is shown that the damage variable based on the effective bearing area and stress around the crack can represent the morphology and expansion change of crack of coal-rock mass with different electrohydraulic parameters clearly and quantitatively. Different hydrostatic pressures and discharge voltages have influence on the damage variables of coal-rock mass, but different influencing degrees cause different damages on coal-rock mass. The damage of coal rock can be characterized by the change of the effective bearing area and stress around microcracks in coal body. So, stress testing and numerical simulation have verified the correctness of the damage model.

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“…Since the impact of thermal changes effects on the coal's permeability cannot be ignored (Perera et al, 2012;Li et al, 2020), we extended the matrix porosity and permeability model proposed by Zhang et al (2008) to encompass the effect of the temperature on permeability. Using this extended model, the dynamic evolution of matrix porosity and permeability evolution during temperature changes can be calculated from the following Eq.…”

Section: Governing Equation For Coal Seam Porosity and Permeabilitymentioning

confidence: 99%

Optimum Layout of Multiple Tree-type Boreholes in Low-Permeability Coal Seams to Improve Methane Drainage Performance

Zhang

Deng

et al. 2021

Front. Energy Res.

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Extracting coal mine methane (CMM) is important for underground mining safety. The tree-type borehole drainage (TTBD) technique can effectively remove methane from coal seams. Determining a suitable drilling pattern for multiple tree-type boreholes will promote the efficient application of this technique in coal mines. Aimed at solving the problem that the optimum methane extraction layout for multiple tree-type boreholes is unclear, this study first constructed a full-coupled thermo-hydro-mechanical model to simulate methane flow in coal. This model and data from a coal mine were used to investigate the effect of multiple tree-type borehole layouts, tree-type borehole spacing, different Langmuir volume and different Langmuir pressure constants, and initial coal permeabilities on CMM drainage. The results show that the different tree-type borehole layouts result in significant differences in drainage and that the use of a rhombic sub-borehole layout can reduce the methane pre-drainage time by up to 44.4%. As the tree-type borehole spacing increases, the total time required for pre-drainage increases as a power function. As the Langmuir pressure constant, the fracture permeability, or the matrix permeability increases, the effective drainage zone expands. The effective drainage zone also expands when the Langmuir volume constant decreases but all these changes are accompanied by a shortening of the drainage completion time. These results can provide a reliable basis for optimizing tree-type borehole drilling layouts.

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Experimental study on damage and the permeability evolution process of methane-containing coal under different temperature conditions

Cited by 42 publications

References 55 publications

Investigation of the CO₂ Flooding Behavior and Its Collaborative Controlling Factors

Investigation of the CO₂ Flooding Behavior and Its Collaborative Controlling Factors

Study on the Damage Model of Coal Rock Caused by Hydraulic Pressure and Electrical Impulse in Borehole

Optimum Layout of Multiple Tree-type Boreholes in Low-Permeability Coal Seams to Improve Methane Drainage Performance

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Experimental study on damage and the permeability evolution process of methane-containing coal under different temperature conditions

Cited by 42 publications

References 55 publications

Investigation of the CO2 Flooding Behavior and Its Collaborative Controlling Factors

Investigation of the CO2 Flooding Behavior and Its Collaborative Controlling Factors

Study on the Damage Model of Coal Rock Caused by Hydraulic Pressure and Electrical Impulse in Borehole

Optimum Layout of Multiple Tree-type Boreholes in Low-Permeability Coal Seams to Improve Methane Drainage Performance

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Investigation of the CO₂ Flooding Behavior and Its Collaborative Controlling Factors

Investigation of the CO₂ Flooding Behavior and Its Collaborative Controlling Factors