Yujialiang Coal Mine, CHN Energy Shendong Coal Group

通过建立二元气体扩散场—渗流场—传热场的耦合方程,利用COMSOL模拟了不同温度和压力下CO2驱替CH4过程中驱替效果、CO2储存量、CH4产量及煤体渗透率等的变化规律。结果表明:CO2驱替作用会导致煤体部分区域出现CH4压力上升高于原始储层压力的现象。随着驱替压力的增大,CO2储存量与CH4产量增加,当驱替压力由2MPa增高到6MPa时,驱替比由2.85增大到4.38。而当注入温度从20℃增高至100℃时,驱替比由4.38降低至4.34。在驱替开采过程中,驱替压力是影响驱替效果的主要因素。随着驱替的进行,CO2影响范围逐渐增大。在CO2影响区域,CO2的注入对煤层渗透率影响较大,煤基质对CO2的吸附使煤层渗透率迅速下降;而在CO2未影响区域,煤体渗透率随着CH4的解吸而增大。

In this study, the coupling equation of binary gas diffusion - seepage - heat transfer field was established. COMSOL was used to simulate the change laws of displacement effect, CO2 storage, CH4 production and coal permeability during CO2 displacement of CH4 at different temperatures and pressures. The results show that CO2 displacement will lead to CH4 pressure rising higher than the original reservoir pressure in some area. CO2 storage and CH4 production increase with the increase of displacement pressure. When the displacement pressure increases from 2 MPa to 6 MPa, the displacement ratio increases from 2. 85 to 4. 38. However, when the displacement temperature increases from 20 ℃ to 100 ℃ , the displacement ratio decreases from 4. 38 to 4. 34. In the process of displacement mining, displacement pressure is the main factor affecting the displacement effect. With the displacement, the influence range of CO2 gradually increases. In the area affected by CO2, the CO2 injection has a great influence on the permeability of coal seam, the adsorption of CO2 by coal matrix makes the permeability of coal seam decrease rapidly. In the area unaffected by CO2, the coal permeability increases with the desorption of CH4.

郄建宇. 注热 CO2 增产 CH4 过程数值模拟研究[J]. 矿业安全与环保,2023,50(5):76-81.

QIE Jianyu. Numerical simulation of heat CO2 injection to increase CH4 [J]. Mining Safety & Environmental Protection,2023,50(5):76-81.