An experimental investigation of applicability of CO 2 enhanced coal bed methane recovery to low rank coal

Ranathunga, A.S.; Perera, M.S.A.; Ranjith, P.G.; Wei, Chenhui

doi:10.1016/j.fuel.2016.10.116

Cited by 88 publications

(36 citation statements)

References 26 publications

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“…The injection pressure was 2.5 MPa [28]. When the flow of ejected gas was stable, the gas flow was used to calculate permeability [29,30]. The permeability experiments on Φ50 × 100 mm sandstone specimens taken from different directions showed that the sandstone has isotropic properties, so the permeability at a single direction can represent the permeability of sandstone [31].…”

Section: Resultsmentioning

confidence: 99%

A New Tree-Type Fracturing Method for Stimulating Coal Seam Gas Reservoirs

et al. 2017

Energies

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Hydraulic fracturing is used widely to stimulate coalbed methane production in coal mines. However, some factors associated with conventional hydraulic fracturing, such as the simple morphology of the fractures it generates and inhomogeneous stress relief, limit its scope of application in coal mines. These problems mean that gas extraction efficiency is low. Conventional fracturing may leave hidden pockets of gas, which will be safety hazards for subsequent coal mining operations. Based on a new drilling technique applicable to drilling boreholes in coal seams, this paper proposes a tree-type fracturing technique for stimulating reservoir volumes. Tree-type fracturing simulation experiments using a large-scale triaxial testing apparatus were conducted in the laboratory. In contrast to the single hole drilled for conventional hydraulic fracturing, the tree-type sub-boreholes induce radial and tangential fractures that form complex fracture networks. These fracture networks can eliminate the "blank area" that may host dangerous gas pockets. Gas seepage in tree-type fractures was analyzed, and gas seepage tests after tree-type fracturing showed that permeability was greatly enhanced. The equipment developed for tree-type fracturing was tested in the Fengchun underground coal mine in China. After implementing tree-type fracturing, the gas extraction rate was around 2.3 times greater than that for traditional fracturing, and the extraction rate remained high for a long time during a 30-day test. This shortened the gas drainage time and improved gas extraction efficiency.

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Section: Resultsmentioning

confidence: 99%

A New Tree-Type Fracturing Method for Stimulating Coal Seam Gas Reservoirs

et al. 2017

Energies

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“…The ECBM is defined as the enhancement of methane desorption rates using a technique that eventually increases methane production from coal beds. There are various ways to implement ECBM method (Puri and Yee, 1990;Wilson et al, 1995;Chaback 1996;Gunter et al, 1997;Parakh, 2007;White et al, 2005;Mazzotti et al, 2009;Busch and Gensterblum, 2011;Ranathunga et al, 2017;Sampath et al, 2017) and of various ECBM techniques, CO 2 injection based methods have become popular due to their added contribution in reducing the greenhouse gas effect through arresting CO 2 into the coal seams. This process is quite simple, as coal prefers carbon dioxide, and it releases methane to sorb injected CO 2 .…”

Section: Extraction Of Coal Bed Methanementioning

confidence: 99%

A brief overview of CBM Development in India

Sain¹,

Vadapalli²,

Vedanti³

2020

PINSA

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Usage of coal as a source of clean energy is a priority area for Govt. of India to meet the overall objective of a low carbon path; hence Clean Coal Technology (CCT) is being pursued under a National Mission Program. The CCT is a broader term that includes all the technologies which can help reduce emissions during various stages of the coal cycle.Exploration and production of Coal Bed Methane (CBM) and its commercial utilization also comes under a larger umbrella of CCT. Studies show that the CBM reserves in Gondwana basin of India hold significant prospects to ensure sustainable energy supply in the future, and provide a potential option for CO 2 sequestration. According to the DGH, prognosticated CBM resources are about 92 TCF in 12 states of India and the commercial production of CBM in India has already commenced w.e.f. July 2007 in Raniganj (South) block in West Bengal. In this paper, we present a brief overview of development of Coal Bed Methane (CBM) and Coal Mine Methane (CMM) in India.

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“…During the permeability test, leakage tests were conducted first when confining stress was increased, which involved testing for stability in the oil volume under the given stress. After confirming the non-leaking condition, volumetric strain of the confined coal sample can be calculated by considering the volume change of the syringe pump and applying the confining stress [32]. Under a certain confining stress, excess oil was pumped out into the syringe pump when the coal sample swells and, meanwhile, the varying volume was recorded.…”

Section: Adsorption Experimental Apparatusmentioning

confidence: 99%

“…Under a certain confining stress, excess oil was pumped out into the syringe pump when the coal sample swells and, meanwhile, the varying volume was recorded. Thus, the volumetric strain of the sample under various injection conditions can be calculated by Equation (1) [32].…”

Section: Co 2 Phasementioning

confidence: 99%

Effects of Coal Deformation on Different-Phase CO2 Permeability in Sub-Bituminous Coal: An Experimental Investigation

et al. 2018

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Coal deformation is one of the leading problems for carbon dioxide (CO2) sequestration in coal seams especially with respect to different-phase CO2 injection. In this paper, a series of core flooding tests were conducted under different confining stresses (8–20 MPa), injection pressures (1–15 MPa), and downstream pressures (0.1–10 MPa) at 50 °C temperature to investigate the effects of coal deformation induced by adsorption and effective stress on sub-critical, super-critical, and mixed-phase CO2 permeability. Due to the linear relationship between the mean flow rate and the pressure gradient, Darcy Law was applied on different-phase CO2 flow. Experimental results indicate that: (1) Under the same effective stress, sub-critical CO2 permeability > mixed-phase CO2 permeability > super-critical CO2 permeability. (2) For sub-critical CO2 flow, the initial volumetric strain is mainly attributed to adsorption-induced swelling. A temporary drop in permeability was observed. (3) For super-critical CO2 flow, when the injection pressure is over 10 MPa, effective-stress-generated deformation is dominant over the adsorption-induced strain and mainly contributes to the volumetric strain change. Thus, there is a linear increase of the volumetric strain with mean pore pressure and super-critical CO2 permeability increased with volumetric strain. (4) For mixed-phase CO2 flow, coupling effects of adsorption-induced swelling and effective stress on the volumetric strain were observed but effective stress made more of a contribution. CO2 permeability consistently increased with the volumetric strain. This paper reveals the swelling mechanism of different-phase CO2 injections and its effect on coal permeability.

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An experimental investigation of applicability of CO 2 enhanced coal bed methane recovery to low rank coal

Cited by 88 publications

References 26 publications

A New Tree-Type Fracturing Method for Stimulating Coal Seam Gas Reservoirs

A New Tree-Type Fracturing Method for Stimulating Coal Seam Gas Reservoirs

A brief overview of CBM Development in India

Effects of Coal Deformation on Different-Phase CO2 Permeability in Sub-Bituminous Coal: An Experimental Investigation

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