Temporal and Spatial Evolutions of Permeability During CBM Drainage Under Different Initial Conditions

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• 作者：Jiang Xu ; Yuexia Chen ; Tingxiang Chu ; Shoujian Peng ; Dan Feng…
• 关键词：Permeability ; Coalbed methane ; Drainage ; Temporal and spatial evolution
• 刊名：Transport in Porous Media
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：116
• 期：2
• 页码：645-662
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Geotechnical Engineering & Applied Earth Sciences; Industrial Chemistry/Chemical Engineering; Hydrology/Water Resources; Civil Engineering; Hydrogeology; Classical and Continuum Physics;
• 出版者：Springer Netherlands
• ISSN：1573-1634
• 卷排序：116

文摘

Physical simulations of coalbed methane (CBM) drainage using different initial gas pressures and different crustal stresses were conducted, and the gas pressures were obtained. The permeability evolutions were calculated based on a permeability model that used the same preconditions and parameters that were obtained from experiments. The permeability decreased rapidly during the initial phase of CBM drainage and then recovered slowly with time. During the initial phase of CBM drainage, the permeability decreased more rapidly near the borehole than further away. The distributions of \(k/k_0 (k\) is permeability, \(k_{0}\) is initial permeability) on the section, surface and longitudinal section that were analyzed were all funnel-shaped, and the distributions were shaped like circular rings, circular cones and circular cones, respectively. After a period of time, the permeability near the borehole recovered slightly, and the distributions of \(k/k_0\) reversed. At the end of CBM drainage, the values of \(k/k_0\) on the section, surface and longitudinal section were almost equal. The higher the crustal stress, the more slowly the permeability decreased, and the higher the initial gas pressure, the more rapidly the permeability decreased.