Impact of dissolution of syngenetic and epigenetic minerals on coal permeability

Ramandi, Hamed Lamei; Liu, Min; Tadbiri, Sahand; Mostaghimi, Peyman

doi:10.1016/j.chemgeo.2018.03.015

Cited by 37 publications

(10 citation statements)

References 70 publications

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“…X-ray CT experiment is widely used for performing the digital rock analysis (Bultreys et al, 2016a;Ramandi et al, 2018;Tahmasebi et al, 2017;Wildenschild and Sheppard, 2013). In our study, each sample was scanned twice using low-and high-resolution CT machine, which is shown schematically in Fig.…”

Section: X-ray Computed Tomographymentioning

confidence: 99%

Effects of micropores on geometric, topological and transport properties of pore systems for low-permeability porous media

Tahmasebi

Lin

et al. 2019

Journal of Hydrology

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Section: X-ray Computed Tomographymentioning

confidence: 99%

Effects of micropores on geometric, topological and transport properties of pore systems for low-permeability porous media

Tahmasebi

Lin

et al. 2019

Journal of Hydrology

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“…The permeability of a rock mainly depends on its pore space properties, i.e. porosity, pore size distribution, connectivity, fracture dimensions, fracture density and degree of mineralization (Jing et al 2017;Mostaghimi et al 2016;Pittman 1992;Ramandi et al 2016Ramandi et al , 2018bSnow 1968;Wong et al 1984). It also can be a highly non-linear dynamic function of mining induced stress and subsequent fractures (Adhikary and Wilkins 2012;Guo and Yuan 2015;Guo et al 2012;Kelsall et al 1984;Wang and Park 2002).…”

Section: Hydraulic Propertiesmentioning

confidence: 99%

Analysis of the influence of groundwater and the stress regime on bolt behaviour in underground coal mines

Smith

Ramandi

Zhang

et al. 2019

Int J Coal Sci Technol

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The service failure of rock bolts and cable bolts are frequently reported issues in underground coal mines. Whilst numerous experimental investigations concerned with the service failure of bolts have been conducted, numerical modelling offers an alternative approach in evaluating the factors contributing to service failures of bolts in underground mines. In this study, analysis of the influence of groundwater and tensile stress on bolts in underground coal mines was studied through the numerical modelling of a grouted bolt in the immediate roadway roof. Bolt tensile stress and groundwater dripping rates in the immediate roadway roof were analysed using a package based on finite element method to assess the effect of coal roof thickness and claystone bands, as main contributors of known service failures of bolts in roadways of underground coal mines. Increasing coal roof thickness was found to increase bolt dripping rates. Probable location of stress corrosion cracking (SCC) occurrence was established through examining the shift and increase in maximum bolt tensile stress that was exhibited along the bolt length with increasing coal roof thickness. Claystone bands situated at the top and centre horizon of a grouted bolt produced lower bolt dripping rates compared with scenarios with no claystone bands. Intersecting claystone bands at the centre horizon of a bolt for a fully grouted bolt could increase the likelihood of SCC corrosion and bolt failure by contributing to microbial corrosion processes and grout fracturing by tensile stress. This study improves the understanding the bolt failure associated with the presence of groundwater and changing stress environments, which in turn is imperative in formulating strategies to mitigate support element failures and improve the ground support viability.

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“…Fracture-filling calcite belongs to epigenetic minerals arising from precipitations of hydrothermal fluids or groundwater. 19,45,46 The direction of fluid migration is controlled by fracture, so that calcite is mainly deposited and filled in a coal fracture system. The observation results using a microscope or a scanning electron microscope confirmed that the fracture can be completely or partially filled with calcite.…”

Section: Introductionmentioning

confidence: 99%

Permeability Enhancement via Acetic Acid (CH₃COOH) Acidizing in Coals Containing Fracture-Filling Calcite

Chen

Wang

2021

Energy Fuels

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Calcite is one of the most common fracture-filling minerals in low-permeability coal seams and can be dissolved easily by acid. Although much attention has been paid recently to coal seam acidizing, only few studies have focused on the permeability evolution during the injection of organic acid, which has a very different reaction rate and dissolution structure morphology from those of conventional strong acids (e.g., HCl and HF). In this study, 0.25−1.0 mol/L acetic acid (CH 3 COOH) was injected into the coal plug samples from the Fuxin Basin in China, whose fractures were completely infilled by calcite. The evolution of plug permeability during CH 3 COOH flooding was monitored. Before and after flooding experiments, the coal plugs were characterized using micro-computed tomography imaging, scanning electron microscopy, and nuclear magnetic resonance. The results showed that fracture-filling calcite exhibits high reactivity after exposure to CH 3 COOH at the temperatures of 20, 30, and 40 °C, and the macro-/microscale highly conductive flow channels between the inlet and the outlet of coal plugs can be formed in several hours. Thus, a significant permeability improvement from less than 0.02 mD to over 27 mD was observed during CH 3 COOH flooding. These increases ranging from 131 to 2720 times of the initial permeability are mainly due to the presence of fracture-filling calcite with high connectivity and the absence of fine migration, clay swelling, and secondary Fe-rich precipitation in the CH 3 COOH environment. The results also suggested that the minimum volume of CH 3 COOH required for a highly conductive flow channel breakthrough can be less than 1.0 PV. This investigation demonstrated the potential of deep matrix-acidizing treatment using CH 3 COOH for improving the permeability and enhanced coalbed methane recovery in coal seams containing fracture-filling calcite.

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Impact of dissolution of syngenetic and epigenetic minerals on coal permeability

Cited by 37 publications

References 70 publications

Effects of micropores on geometric, topological and transport properties of pore systems for low-permeability porous media

Effects of micropores on geometric, topological and transport properties of pore systems for low-permeability porous media

Analysis of the influence of groundwater and the stress regime on bolt behaviour in underground coal mines

Permeability Enhancement via Acetic Acid (CH₃COOH) Acidizing in Coals Containing Fracture-Filling Calcite

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Impact of dissolution of syngenetic and epigenetic minerals on coal permeability

Cited by 37 publications

References 70 publications

Effects of micropores on geometric, topological and transport properties of pore systems for low-permeability porous media

Effects of micropores on geometric, topological and transport properties of pore systems for low-permeability porous media

Analysis of the influence of groundwater and the stress regime on bolt behaviour in underground coal mines

Permeability Enhancement via Acetic Acid (CH3COOH) Acidizing in Coals Containing Fracture-Filling Calcite

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Permeability Enhancement via Acetic Acid (CH₃COOH) Acidizing in Coals Containing Fracture-Filling Calcite