Coalbed methane reservoir fracture evaluation through the novel passive microseismic survey and its implications on permeable and gas production

Tian, Lin; Cao, Yongzhi; Liu, Shimin; Shi, Bin; Liu, Jianzhong; Elsworth, D.

doi:10.1016/j.jngse.2020.103181

Cited by 22 publications

(11 citation statements)

References 30 publications

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“…Gas production from coal not only provide clean energy, but also improve the safe mining when coal is being mined (Yuan 2016;Cao et al 2017;Zou et al 2021;Tian et al 2020). Coal is known as its low permeability due to its tight structure (Liu and Harpalani 2013;Zhai et al 2016;Zou et al 2015;Guo et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the adverse effect of gel fracturing fluid on gas sorption behavior for Illinois coal

Huang

Liu

et al. 2021

Int J Coal Sci Technol

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Hydraulic fracturing is an effective technology for coal reservoir stimulation. After fracturing operation and flowback, a fraction of fracturing fluid will be essentially remained in the formation which ultimately damages the flowability of the formation. In this study, we quantified the gel-based fracturing fluid induced damages on gas sorption for Illinois coal in US. We conducted the high-pressure methane and CO2 sorption experiments to investigate the sorption damage due to the gel residue. The infrared spectroscopy tests were used to analyze the evolution of the functional group of the coal during fracturing fluid treatment. The results show that there is no significant chemical reaction between the fracturing fluid and coal, and the damage of sorption is attributed to the physical blockage and interactions. As the concentration of fracturing fluid increases, the density of residues on the coal surface increases and the adhesion film becomes progressively denser. The adhesion film on coal can apparently reduce the number of adsorption sites for gas and lead to a decrease of gas sorption capacity. In addition, the gel residue can decrease the interconnectivity of pore structure of coal which can also limit the sorption capacity by isolating the gas from the potential sorption sites. For the low concentration of fracturing fluid, the Langmuir volume was reduced to less than one-half of that of raw coal. After the fracturing fluid invades, the desorption hysteresis of methane and CO2 in coal was found to be amplified. The impact on the methane desorption hysteresis is significantly higher than CO2 does. The reason for the increasing of hysteresis may be that the adsorption swelling caused by the residue adhered on the pore edge, or the pore blockage caused by the residue invasion under high gas pressure. The results of this study quantitatively confirm the fracturing fluid induced gas sorption damage on coal and provide a baseline assessment for coal fracturing fluid formulation and technology.

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Section: Introductionmentioning

confidence: 99%

Experimental study on the adverse effect of gel fracturing fluid on gas sorption behavior for Illinois coal

Huang

Liu

et al. 2021

Int J Coal Sci Technol

Self Cite

View full text Add to dashboard Cite

show abstract

“…Gas production from coal cannot only provide clean energy, but improve the safe mining when coal is being mined (Yuan 2016Cao et al 2017Tian et al 2020). Coal is known as its low permeability due to its tight structure (Liu and Harpalani 2013;Zhai et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Adverse Effect of Gel Fracturing Fluid on Gas Sorption Behavior for Illinois Coal

Huang

Liu

et al. 2021

Preprint

Self Cite

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Hydraulic fracturing is an effective technology for coal reservoir stimulation. After fracturing operation and flowback, a fraction of fracturing fluid will be essentially remained in the formation which ultimately damages the flowability of the formation. In this study, we quantify the gel-based fracturing fluid induced damages on gas sorption for Illinois coal in US. We conducted the high-pressure methane and CO2 sorption experiments to investigate the sorption damage due to the gel residue. The infrared spectroscopy tests were used to analyze the evolution of the functional group of the coal during fracturing fluid treatment. The results show that no significant chemical alteration of coal due to the fracturing fluid injection, and the damage of sorption is attributed to the physical blockage and interactions. As the concentration of fracturing fluid increases, the density of residues on the coal surface increases and the adhesion film becomes progressively denser. The adhesion film on coal can apparently reduce the number of adsorption sites for gas and lead to a decrease of gas sorption capacity. In addition, the gel residue can decrease the interconnectivity of pore structure of coal which can also limit the sorption capacity by isolating the gas from the potential sorption sites. For the low concentration of fracturing fluid, the Langmuir volume was reduced to less than one-half of that of raw coal. After the fracturing fluid invades, the desorption hysteresis of methane and CO2 in coal was found to be amplified. The impact on the methane desorption hysteresis is significantly higher than CO2 does. The reason for the increasing of hysteresis may be that the adsorption swelling caused by the residue adhered on the pore edge, or the pore blockage caused by the residue invasion under high gas pressure. The results of this study quantitatively confirm the fracturing fluid induced gas sorption damage on coal and provide a baseline assessment for coal fracturing fluid formulation and technology.

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“…It is pointed out that both methods are expensive, and for the area where coal cores cannot be obtained by drilling or without mining work, because of which determination of coal structures has become technically infeasible . Geophysical well log data are widely available through geological survey and have recently been used to evaluate the reservoir properties of coals such as gas content, mechanical properties, macrolithotypes, permeability, and coal texture by analyzing the responses in terms of magnetic, acoustic, electrical, and nuclear methods from geological well log data. − Coal structure identification with the help of well log data have been studied and it can accurately characterize the distribution of coal structures . With the increase of deformation intensity of coals, the basic response characters and identification laws by using logging data are shown in Table…”

Section: Introductionmentioning

confidence: 99%

Analysis of Logging Identification and Methane Diffusion Properties of Coals with Various Deformation Structures

Zhang

Meng

Li³

2021

Energy Fuels

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Methane diffusion in coals with different deformations is important for gas resource evaluation. In this study, the adsorption/ desorption and diffusion behavior in different coal structures were investigated, and the multi-logging parameter model of backpropagation (BP) neural network was employed to identify coal structures, as well as the effects of diffusion changes on gas contents in the study area, were revealed. The results indicate that with the increase of coal deformation intensity, the Langmuir V L increases, and both specific surface area and pore volume increase as well. Diffusion coefficients in coals decrease gradually with the decrease of pressures, and the development of meso/macropores and micropores in tectonic coals promotes gas migration, which increase the diffusion efficiency, especially the fast and reduction diffusion stages (S1 and S2).Comparisons between intact and tectonically deformed coals in terms of gas diffusion behaviors modeled by the unipore and bidisperse numerical methods show that the analytical solution of the bidisperse model is more appropriate to describe diffusion behaviors in tectonic coals due to the enhanced complexity of mesopores and micropores in coals. Different coal structures exhibiting similar values in well logs lead to multiple interpretations of coal structures. The proposed BP model is an effective way to identify the nonlinear relationships between well logs and coal structures by extracting key information from logging datasets. The modeled results show that the degree of heterogeneity of the gas content in different coal structures is high and the higher diffusion rate in granulated coal zone somewhat reduced the measured gas content.

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Coalbed methane reservoir fracture evaluation through the novel passive microseismic survey and its implications on permeable and gas production

Cited by 22 publications

References 30 publications

Experimental study on the adverse effect of gel fracturing fluid on gas sorption behavior for Illinois coal

Experimental study on the adverse effect of gel fracturing fluid on gas sorption behavior for Illinois coal

Experimental Study on the Adverse Effect of Gel Fracturing Fluid on Gas Sorption Behavior for Illinois Coal

Analysis of Logging Identification and Methane Diffusion Properties of Coals with Various Deformation Structures

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