Asif Mohammad, Wang Lei, Panigrahi D C, Ojha Keka, Hazlett Randy
School of Mining and Geosciences, Nazarbayev University, Kabanbay Batyr Ave 53, Nur-Sultan, 010000, Kazakhstan.
College of Energy, Chengdu University of Technology, Chengdu, 610059, China.
Sci Rep. 2022 May 9;12(1):7533. doi: 10.1038/s41598-022-10574-5.
Coalbed methane (CBM) production is effectively achieved by utilizing two processes, viz. primary and secondary recovery. In this paper, the primary recovery of CBM was studied using the adsorption isotherm while CO-ECBM process for the secondary recovery was simulated with realistic parameters. The adsorption isotherm for CH was drawn up to the pressure of 1200 psi for four coal samples and Langmuir isotherm curves for both CH and CO was measured for one sample up to 2000 psi. The adsorption isotherm of four samples was further utilized for finding the primary recovery factor of methane, showing that the average primary recovery is ~ 54% with the highest recovery factor of ~ 76% for one sample. Hence, CO-ECBM process could be further implemented to enhance gas recovery. Then, a 3D heterogeneous coalbed model at a depth of 3219 ft was constructed using the COMET3 simulator to demonstrate the potential of CO-ECBM recovery technique. A concept of break-even time was introduced in this study for the comprehension of CO-ECBM process. It is found that coalbed reservoirs may opt to implement this technology with economically sound recovery.
煤层气（CBM）的生产可通过两种工艺有效实现，即一次采气和二次采气。本文利用吸附等温线研究了煤层气的一次采气，并使用实际参数模拟了用于二次采气的CO-ECBM工艺。绘制了四个煤样在1200 psi压力下的CH吸附等温线，并测量了一个样品在2000 psi压力下CH和CO的朗缪尔等温线曲线。进一步利用四个样品的吸附等温线来确定甲烷的一次采收率，结果表明平均一次采收率约为54%，其中一个样品的最高采收率约为76%。因此，可以进一步实施CO-ECBM工艺以提高气藏采收率。然后，使用COMET3模拟器构建了一个深度为3219英尺的三维非均质煤层模型，以展示CO-ECBM采收技术的潜力。本研究引入了收支平衡时间的概念，以理解CO-ECBM工艺。结果发现，煤层气藏可以选择以经济上合理的采收方式实施该技术。
