Numerical study of multi-branch horizontal well coalbed methane extraction

Fan, Yu; Deng, Cunbao; Zhang, Xun; Li, Fengqi; Wang, Xin-Yang

doi:10.1080/15567036.2018.1476616

Cited by 10 publications

(4 citation statements)

References 17 publications

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“…Due to the poor permeability of deep coal beds, the development effect of fracturing straight wells is not ideal (Fei et al, 2015;Cao et al, 2016;Ali et al, 2017;Su et al, 2018). How to improve the gas production is a major problem faced by China's deep CBM development (Song et al, 2015;Sun et al, 2016;Fan et al, 2018). The horizontal well is a very important stimulation technology, which has the advantages of small well pad area, large discharge area, high gas production of single well, and quick capital recovery (Liu et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Geological adaptability of deep CBM fractured horizontal well in SLN block

Yuan

et al. 2023

Front. Earth Sci.

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The buried depth of the main coal beds in SLN Block is more than 1,500 m, and the gas content of the coal beds is high. However, the coal beds are generally in a high geostress environment, the permeability of the coal beds is generally low, and the development effect of conventional fractured straight wells is poor. Fractured horizontal well is an important technical means to improve the development effect of low permeability coalbed methane, but the investment cost is high. To reduce the investment risk of fractured horizontal wells, it is necessary to find out the gas production capacity and main control factors of the fractured horizontal wells, and determine the area suitable for the development of fractured horizontal wells. In the area with permeability higher than 0.28 md and gas content higher than 12.8 m3/t, the daily gas production capacity of fractured horizontal well is 16,450–21500 m3/d, and the development effect is good. The research results are of great significance to quickly evaluate the adaptability of fractured horizontal wells.

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Section: Introductionmentioning

confidence: 99%

Geological adaptability of deep CBM fractured horizontal well in SLN block

Yuan

et al. 2023

Front. Earth Sci.

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“…Numerical simulation is usually applied to the formulation and optimization of CBM well production system. Numerical simulation is a key technology to study the laws of CBM storage, transportation, and accumulation (Kang et al., 2019; Zhao et al., 2019), and also to explain the coal seam parameters, formulate the CBM well production system, and predict CBM production (Fan et al., 2018a; Sun et al., 2018). However, the numerical simulation of CBM well multilayer drainage is at its early stages and requires further analyses to understand the involved mechanism and key engineering parameters such as drainage rate.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of drainage rate for multilayer drainage coalbed methane well group in Southern Qinshui basin

Hu¹,

Liu

Sang

et al. 2020

Energy Exploration & Exploitation

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Multilayer drainage is one of the important technologies for coalbed methane (CBM) production in China. In this study, a multi-field fully coupled mathematical model for CBM production was established to analyze the multilayer drainage of CBM well group in southern Qinshui basin. Based on the numerical simulation results, the characteristics of CBM well production under different drainage rates and key factors influencing the CBM production were further discussed. The results show that the effect of an increased drainage rate on gas production of CBM wells and CBM recovery of No.3 coal seam is not significant. However, it significantly improved the gas production of CBM wells and CBM recovery of No.15 coal seam. After a long period of production, the CBM content in No.3 coal seam has reduced to a low level and the pressure drop potential of No.3 coal seam is insignificant, which are important reasons for the insignificant increase of CBM production even under a drainage rate of 2 to 7 times. Conversely, No.15 coal seam has larger residual CBM content and increasing the drainage rate can significantly improve the pressure drop and superimposed well interference of No.15 coal seam, which means No.15 coal seam has greater production potential than No.3 coal seam. Therefore, it is recommended to improve the gas production and CBM recovery in No.15 coal seam by increasing the drainage rate, and the average hydraulic pressure drop should be 0.018–0.031 MPa/day. The influence of effective stress is weak in No.3 and No.15 coal seam, and the coal seam permeability is largely influenced by the shrinkage of coal matrix caused by CBM desorption. This indicates the feasibility of increase in gas production from CBM wells by increasing the drainage rate.

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“…Several studies focused on MBHW technology, mainly via numerical simulations and field tests . Ren et al used field pilot data and indicated that the performance levels of MBHWs are relatively stable when compared with those of most fractured vertical wells.…”

Section: Introductionmentioning

confidence: 99%

“…Liu et al constructed a model to predict the pressure decline and the production levels of MBHWs. Fan et al established a hydraulic‐mechanical‐thermal coupled model of MBHW CMB extraction. However, many influencing factors were not explored using the approach due to the limitations of numerical simulations such as the simplifications and assumptions in numerical models .…”

Section: Introductionmentioning

confidence: 99%

Different adsorbed gas effects on the reservoir parameters and production in coalbed methane extraction by multibranch horizontal wells

Peng

Yan

et al. 2019

Energy Science & Engineering

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Coalbed methane (CBM) is an efficient energy source that mainly contains CH4 and CO2. Multibranch horizontal wells (MBHWs) are widely used in CBM extraction. In the study, CH4 and CO2 were employed to perform CBM extraction experiments by MBHWs. Based on the experiments, a phenomenon occurs wherein gas from the high‐pressure production layer enters the low‐pressure production layer during the initial stage. Reservoir pressure, temperature, permeability, and instantaneous flow rate exhibit similar evolution laws. Specifically, they initially increase sharply, then declining rapidly, and finally level off in the production layer with the minimum initial pressure. Increase in the adsorption capacity lowers the increase in reservoir pressure, although the phenomenon persists longer from appearance to disappearance. The moment of permeability recovery is related to the adsorption capacity, and the moment of permeability recovery under CO2 conditions occurs after that under CH4 conditions. The instantaneous flow rate curve is divided into three categories, namely steep flow rate increase curve, flow rate inhibition curve, and backflow curve. The results are useful for CBM extraction of multiple coal seams.

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Numerical study of multi-branch horizontal well coalbed methane extraction

Cited by 10 publications

References 17 publications

Geological adaptability of deep CBM fractured horizontal well in SLN block

Geological adaptability of deep CBM fractured horizontal well in SLN block

Numerical analysis of drainage rate for multilayer drainage coalbed methane well group in Southern Qinshui basin

Different adsorbed gas effects on the reservoir parameters and production in coalbed methane extraction by multibranch horizontal wells

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