Yu Yina, Meng Zhaoping
College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, P. R. China.
State Key Laboratory of Coal and CBM Co-Mining, Shanxi Jincheng Anthracite Mining Group Company, Ltd., Jincheng 048000, Shanxi, P. R. China.
ACS Omega. 2021 Jul 14;6(29):18914-18927. doi: 10.1021/acsomega.1c02147. eCollection 2021 Jul 27.
Temperature significantly affects the storage and transport of coalbed methane (CBM). Studies of geothermal distribution characteristics are important for the exploration and exploitation of CBM. In this study, more than 150 heat flow temperature data from coalbed methane wells in the Qinshui Basin were analyzed to investigate the geothermal distribution and its controlling factors. The results show that the geothermal gradient of the no. 3 coal seam ranges from 0 to 3.7 °C/hm with an average of 1.6 °C/hm, and the terrestrial heat flow of the no. 3 coal reservoir ranges from 0.9 to 94.6 mW/m with an average of 41.5 mW/m. The reservoir temperature shows high values in the central and northwest parts of the basin, while the east and west edges of the basin show negative geothermal anomalies. It is found that groundwater has significant effects on the geothermal distribution in the Qinshui Basin, and with the increase of the groundwater level, the geothermal gradient decreases linearly. In addition, the geothermal gradient and terrestrial heat flow first increase and then tend to be stable with the increase in value of the total dissolved substances. Besides, with an increase in floor elevation, the geothermal gradient first increases linearly and then decreases linearly, obtaining a maximum value at about 450 m (transition floor elevation). This phenomenon is the result of the balance between heat supplying and heat losing. The geothermal distribution characteristics in the Qinshui Basin determine the reservoir temperature of the coalbed methane, and in turn, the reservoir temperature affects the adsorption, desorption, and diffusion behaviors of coalbed methane in situ.
温度对煤层气（CBM）的储存和运输有显著影响。地热分布特征研究对于煤层气的勘探与开发具有重要意义。本研究分析了沁水盆地煤层气井150多个热流温度数据，以探究地热分布及其控制因素。结果表明，3号煤层地温梯度范围为0至3.7℃/hm，平均为1.6℃/hm，3号煤储层大地热流范围为0.9至94.6mW/m，平均为41.5mW/m。储层温度在盆地中部和西北部较高，而盆地东、西边缘出现负地热异常。研究发现，地下水对沁水盆地的地热分布有显著影响，随着地下水位的升高，地温梯度呈线性下降。此外，随着总溶解物质含量的增加，地温梯度和大地热流先升高后趋于稳定。另外，随着底板标高的增加，地温梯度先线性升高后线性下降，在约450m（过渡底板标高）处达到最大值。这种现象是供热与散热平衡的结果。沁水盆地的地热分布特征决定了煤层气的储层温度，而储层温度又反过来影响煤层气在原地的吸附、解吸和扩散行为。
