Evaluation of stress-controlled coal swelling processes

被引:172
作者
Liu, Jishan [1 ]
Chen, Zhongwei [1 ]
Elsworth, Derek [3 ]
Miao, Xiexing [2 ]
Mao, Xianbiao [2 ]
机构
[1] Univ Western Australia, Nedlands, WA 6009, Australia
[2] China Univ Min & Technol, State Key Lab Geomech & Underground Engn, Jiangsu, Peoples R China
[3] Penn State Univ, Dept Energy & Mineral Engn, University Pk, PA 16802 USA
关键词
Coal-gas interactions; Stress-controlled sorption; Coal swelling; Coal permeability; Numerical modeling; CO2; SEQUESTRATION; PERMEABILITY CHANGE; METHANE-RECOVERY; CARBON-DIOXIDE; GAS; SORPTION; SEAMS; FLOW; INJECTION; MATRIX;
D O I
10.1016/j.coal.2010.06.005
中图分类号
TE [石油、天然气工业]; TK [能源与动力工程];
学科分类号
0807 ; 0820 ;
摘要
Stress-controlled swelling tests are normally conducted in the laboratory to characterize the evolution of coal permeability under the influence of gas sorption. Typically reductions in permeability are observed from gas-sorption-induced swelling even where effective stresses remain constant. This behavior remains enigmatic as the permeability of the porous coal is determined by the effective stress only. When these observations were interpreted, a matchstick or cubic coal model was assumed. Under this assumption, matrix swelling would not affect coal permeability because of the complete separation between matrix blocks caused by through-going fractures. This is why current coal permeability models have little success in explaining this inconsistency. It is generally believed that the reason for the failure is the inconsistency between the experimental conditions and the model assumptions. However, in this paper, it is considered that the reason may be the internal actions between coal fractures and matrixes have not been taken into consideration. In this study, a model capable of replicating this apparently anomalous behavior is developed. We consider the interactions of the fractured coal mass where cleats do not create a full separation between adjacent matrix blocks but where solid rock bridges are present. We accommodate the role of swelling strains both over contact bridges that hold cleat faces apart but also over the non-contacting span between these bridges. The effects of swelling act competitively over these two components: increasing porosity and permeability due to swelling of the bridging contacts but reducing porosity and permeability due to the swelling of the intervening free-faces. Under these conditions, a new permeability model is formulated. The new model is the key cross link that couples the multiphysics of coal-gas interactions. The formulation and incorporation of this permeability model into the multiphysics simulation of coal-gas interactions are presented in this paper. (C) 2010 Elsevier B.V. All rights reserved.
引用
收藏
页码:446 / 455
页数:10
相关论文
共 39 条
[1]  
Amadei B., 1981, Proceedings of the International Symposium on the Mechanical Behaviour of Structured Media, P249
[2]  
[Anonymous], 2005, INT COALB METH S
[3]   Impact of CO2 injection and differential deformation on CO2 injectivity under in-situ stress conditions [J].
Chen, Zhongwei ;
Liu, Jishan ;
Elsworth, Derek ;
Connell, Luke D. ;
Pan, Zhejun .
INTERNATIONAL JOURNAL OF COAL GEOLOGY, 2010, 81 (02) :97-108
[4]  
Chilingar G., 1963, J SEDIMENT RES, V33, P759
[5]   ANISOTROPIC SOLVENT SWELLING OF COALS [J].
CODY, GD ;
LARSEN, JW ;
SISKIN, M .
ENERGY & FUELS, 1988, 2 (03) :340-344
[6]   Coupled flow and geomechanical processes during gas production from coal seams [J].
Connell, L. D. .
INTERNATIONAL JOURNAL OF COAL GEOLOGY, 2009, 79 (1-2) :18-28
[7]   Coupled flow and geomechanical processes during enhanced coal seam methane recovery through CO2 sequestration [J].
Connell, L. D. ;
Detournay, C. .
INTERNATIONAL JOURNAL OF COAL GEOLOGY, 2009, 77 (1-2) :222-233
[8]   Volumetric strain associated with methane desorption and its impact on coalbed gas production from deep coal seams [J].
Cui, XJ ;
Bustin, RM .
AAPG BULLETIN, 2005, 89 (09) :1181-1202
[9]   Flow of coal-bed methane to a gallery [J].
Gilman, A ;
Beckie, R .
TRANSPORT IN POROUS MEDIA, 2000, 41 (01) :1-16
[10]  
Gray I., 1987, RESERVOIR ENG COAL S, P28, DOI DOI 10.2118/12514-PA