A discussion on analytical and numerical modelling of the land subsidence induced by coal seam gas extraction
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Coal seam gas (CSG) is an increasingly important source of natural gas all over the world. Although the influence of conventional oil and gas extraction on surface subsidence has been widely recognized and studied, few studies are carried out on the surface subsidence in coal seam gas fields and its impact on surface infrastructure and the environment. This paper discusses modelling of the surface subsidence associated with coal seam gas production by applying both analytical and numerical methods. By comparison of results from the numerical model and two analytical models, i.e. the disc-shaped reservoir model and the uniaxial compaction model, the analytical solutions cannot describe the complex process of water and gas extraction and have the limitations to predict the surface subsidence, while the numerical model can be better used in prediction of subsidence. After applying the numerical model in numerical analysis, the deformation characteristics of coupled fluid flow, and the effects of permeability change of coal seam, associated overlying and underlying layers, and depressurization rates on surface subsidence are investigated. The results demonstrate that the proposed model can simulate the production of water and gas from coal seams and the associated surface subsidence.
KeywordsSubsidence Coal seam gas production Depressurization Coal matrix shrinkage COMSOL
The authors gratefully acknowledge the support of the National Natural Science Foundation of China (Grant no. 51379007), the support of the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering (Grant no. Z013007), the Oil and Gas Reservoir Geology and Exploitation (Grant no. PLN1507) and the support of the Youth Innovation Promotion Association, CAS.
Compliance with ethical standards
Conflict of interest
No conflict of interest exists regarding the publication of this paper.
- Asadi A, Shahriar K, Goshtasbi K, Najm K (2005) Development of a new mathematical model for prediction of surface subsidence due to inclined coal-seam mining. J South Afr Inst Min Metall 105(1):15–20Google Scholar
- Australian G (2014) Background review: Subsidence from coal seam gas extraction in Australia. Australian Government Department of the Environment, CanberraGoogle Scholar
- Chamani A, Rasouli V (2011) Simulation of depletion-induced surface subsidence in a coal seam. The 3rd Asia Pacific Coalbed Methane Symposium, Brisbane, Australia, 3–6 May 2011Google Scholar
- COMSOL Group (2013) COMSOL multiphysics: version 4.4Google Scholar
- Fjær E, Holt RM, Raaen AM, Risnes R, Horsrud P (2008) Petroleum related rock mechanics, vol 53. Elsevier, AmsterdamGoogle Scholar
- Freij-youb R (2012) Numerical simulation of the production of methane and water from coal seams and the associated ground surface subsidence, SPE Asia Pacific Oil & Gas Conference & Exhibition, Perth, Australia, 22–24 October 2012Google Scholar
- Pineda JA, Shjeng D (2014) Coal Seam Gas extraction and their potential effects on surface subsidence: an overview. In: Yuen STS, Brown B (eds) Proceedings of the 7th International Congress on Environmental Geotechnics. Engineers Australia, pp 370–379Google Scholar
- Seidle JP, Arri LE (1990) Use of conventional reservoir models for coalbed methane simulation. Society of Petroleum EngineersGoogle Scholar