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

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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Tectonic stress estimation from ultrasonic borehole image logs in a coal bed methane well, northeastern Qinshui Basin, China

Journal of Natural Gas Science and Engineering ◽

10.1016/j.jngse.2018.01.021 ◽

2018 ◽

Vol 52 ◽

pp. 44-58 ◽

Cited By ~ 3

Author(s):

Mingxing Liang ◽

Suping Peng ◽

Wenfeng Du ◽

Yongxu Lu

Keyword(s):

Tectonic Stress ◽

Coal Bed ◽

Coal Bed Methane ◽

Qinshui Basin ◽

Stress Estimation ◽

Borehole Image ◽

Borehole Image Logs

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Production Performance Analysis for Multi-Branched Horizontal Wells in Composite Coal Bed Methane Reservoir Considering Stress Sensitivity

Journal of Energy Resources Technology ◽

10.1115/1.4046524 ◽

2020 ◽

Vol 142 (7) ◽

Cited By ~ 1

Author(s):

Ruizhong Jiang ◽

Xiuwei Liu ◽

Yongzheng Cui ◽

Xing Wang ◽

Yue Gao ◽

...

Keyword(s):

Superposition Principle ◽

Horizontal Wells ◽

Stress Sensitivity ◽

Field Application ◽

Model Verification ◽

Production Performance ◽

Coal Bed ◽

Coal Bed Methane ◽

Element Discretization ◽

Type Curves

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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