Implications of Pressure Interference on Production Performance of Coal Bed Methane CBM wells

Abstract Coal bed methane (CBM) significantly contributes to unconventional energy resources. With the development of the drilling technology, multi-branched horizontal wells (MBHWs) have been put into the exploitation of CBM. In this paper, a semi-analytical mathematical model is introduced to study the production characteristics of MBHWs in the composite CBM reservoir. Stress sensitivity, composite reservoir, and complex seepage mechanisms (desorption, diffusion, and Darcy flow) are taken into consideration. Through Pedrosa transformation, Perturbation transformation, Laplace transformation, Finite cosine transformation, element discretization, superposition principle, and Stehfest numerical inversion, pseudo-pressure dynamic curves and production decline curves are plotted and 13 flow regimes are divided. Then, the sensitivity analysis of related parameters is conducted to study the influences of these parameters based on these two type curves. Model verification and field application are introduced which shows that the model is reliable. The model proposed in this paper and relevant results analysis can provide some significant guidance for a better understanding of the production behavior of MBHWs in the composite CBM reservoir.

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Production performance analysis for horizontal wells in composite coal bed methane reservoir

Energy Exploration & Exploitation ◽

10.1177/0144598716687930 ◽

2017 ◽

Vol 35 (2) ◽

pp. 194-217 ◽

Cited By ~ 7

Author(s):

Zhang Wei ◽

Jiang Ruizhong ◽

Xu Jianchun ◽

Gao Yihua ◽

Yang Yibo

Keyword(s):

Performance Analysis ◽

Flow Regime ◽

Transient Analysis ◽

Horizontal Well ◽

Radial Flow ◽

Production Performance ◽

Coal Bed ◽

Coal Bed Methane ◽

Pressure Transient Analysis ◽

Pressure Transient

In this paper, the mathematical model of production performance analysis for horizontal wells in composite coal bed methane reservoir is introduced. In this model, two regions with different formation parameters are distinguished, and multiple mechanisms are considered including desorption, diffusion, and viscous flow. Then the solution of horizontal well performance analysis model is obtained by using point source function method, Laplace transform, and Stehfest algorithm comprehensively. The solution of the proposed model is verified with previous work thoroughly. The pressure transient analysis for horizontal well when producing at a constant rate is obtained and discussed. At last, different flow regimes are divided based on pressure transient analysis curves. They are early wellbore storage period, skin factor period, first radial flow regime, transition regime, second radial flow regime, transfer regime, and late pseudo-radial flow regime. The effects of related parameters such as storativity ratio, transfer coefficient, adsorption coefficient, ratio of vertical permeability to horizontal permeability, skin factor, horizontal well position in vertical direction, and inner region radius are analyzed as well according to pressure transient analysis and rate transient analysis curves. The presented work in this paper can give a better understanding of coal bed methane production performance in composite reservoir.

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Study on the Mechanism of a Multi-branch Horizontal Well in Enhancing the Production Performance of Coal-Bed Methane Reservoirs in the SY Block, Qinshui Basin

Springer Series in Geomechanics and Geoengineering - Proceedings of the International Field Exploration and Development Conference 2020 ◽

10.1007/978-981-16-0761-5_283 ◽

2021 ◽

pp. 3027-3039

Author(s):

Yu-min Lv ◽

Xue-shen Zhu ◽

Guangshan Guo ◽

Cun-wu Wang ◽

Jiangong Zhang

Keyword(s):

Horizontal Well ◽

Production Performance ◽

Coal Bed ◽

Coal Bed Methane ◽

Qinshui Basin

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Pressure Transient Analysis for Horizontal Wells in Coal Bed Methane Reservoirs with Pressure-Sensitive Permeabilities

10.20944/preprints202108.0316.v1 ◽

2021 ◽

Author(s):

Juan Camilo Sepúlveda ◽

Sebastián Díaz ◽

Edwin Alexander López

Keyword(s):

Flow Behavior ◽

Horizontal Wells ◽

Transient Behavior ◽

Production Performance ◽

Coal Bed ◽

Coal Bed Methane ◽

Coal Seams ◽

Pressure Transient ◽

Type Curves ◽

Flow Mechanisms

Abstract: Coal bed methane (CBM) reservoirs are complex systems whose properties differ from those of conventional reservoirs. Coal seams are dual-porosity systems that comprise the porosities of the matrix and cleat system. Gas in the coal seams can be stored as free gas in the cleat system and as adsorbed gas in the porous medium. The flow mechanisms of the natural gas through the formation include desorption, diffusion, and Darcy’s flow regimes. The permeability of CBM reservoirs is more sensitive to pressure variations than conventional gas reservoirs. To study the flow behavior of CBM reservoirs it is mandatory to use a model that considers their unique characteristics. The objective of this study was to propose a physical and mathematical model of production performance for horizontal wells in CBM reservoirs whose permeability is dependent on pressure. A solution for the model was obtained by applying Pedrosa´s transformation, perturbation theory, Laplace transformation, the point source method, and Sthefest´s algorithm. The solution to this problem was validated with previous work thoroughly. The type curves of the model were built and the pressure transient behavior of the model was analyzed and discussed. The effects of several parameters on pressure behavior were also discussed.

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