Mechanism of production increasing of coalbed gas for the pinnate horizontal well and sensitivity effect of parameters on gas production
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The mechanism of production increasing for the pinnate horizontal well is analyzed with the simulation technique. It is pointed out that the whole horizontal wellbore spreading widely and evenly in coal layers makes the stratum pressure drop evenly and fast, which increases the chance of desorption and diffusion and area controlled. This is the basic reason that the pinnate horizontal well can increase production. How such stratum parameters as permeability, Langmuir constants and adsorption time constant affect the gas production for the pinnate horizontal well is also studied with numerical simulations. Either for the vertical well or the pinnate horizontal well, bigger stratum permeability, steeper relative permeability curve, smaller residual gas saturation, higher gas content and stratum pressure are more favorable for gas production increasing. Langmuir constants decide the change of desorption quantity and influence the gas production through changing the extent of steep of isothermal adsorption curves in the pressure dropping area. The adsorption time constant only influences the time that gas production arrives at the maximum value for the vertical well, but it almost has no influence on the gas production for the pinnate horizontal well because the equivalent adsorption time constant is reduced.
Keywordscoalbed gas pinnate horizontal well mechanism numerical simulation sensitivity effect
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- 1.Fan, M. Z., Wang, S. H., Principal geologic parameters controlling coalbed gas recoverability, Natural Gas Industry (in Chinese), 1996, 6: 53–57.Google Scholar
- 2.Yang, L. W., Sun, M. Y., The particularity of coalbed gas reservoir in China and technology requirement of production, Natural Gas Industry (in Chinese), 2001, 6: 17–19.Google Scholar
- 3.Li, W. Y., Wang, S. Y., Zhao, Q. B., Exploration & Production of Coalbed Gas in China (in Chinese), Xuzhou: Mining College of China Press, 2003, 1–38, 161–200, 201–219.Google Scholar
- 4.Smith, M., Chasing unconventional gas unconventionally, New Technology Magazine, 2003, Oct/Nov: 1–4.Google Scholar
- 5.Zhang, D. L., Wang, X. H., Simulation study of coalbed methane single well production, Journal of Jianghan Petroleum Institute (in Chinese), 2004, 1: 76–77.Google Scholar
- 6.Liu, X. P., Guo, C. Z., Jiang, Z. X. et al., The model coupling fluid flow in the reservoir with flow in the horizontal wellbore, Acta Petrolei Sinica (in Chinese), 1999, 3: 82–86.Google Scholar
- 7.Zhang, D. L., Wang, X. H., Mechanism study of coalbed methane single sell production, Journal of Jianghan Petroleum Institute (in Chinese), 2004, 3: 124–126.Google Scholar
- 8.Kolesar, J. E., Ertekin, T., Obut, S. T., The unsteady state nature of sorption and diffusion phenomena in the micropore structure of coal: Part2-Solution, SPEFE, 1990, 5(3): 89–97.Google Scholar
- 9.Kuuskraa, V. A., Wicks, D. E., Thurber, J. L., Geologic and reservoir mechanisms controlling gas production from the Antrim shale, SPE24883: 209–224.Google Scholar