CO_(2)或N_(2)驱替煤中CH_(4)实验研究  

Experimental study on CO_(2) or N_(2) displacement of CH_(4) in coal

作　　者：龚月 高和群 李小越 陈云燕 GONG Yue;GAO Hequn;LI Xiaoyue;CHEN Yunyan(SINOPEC East China Oil and Gas Company Exploration and Development Research Institute,Jiangsu Yangzhou 225007,China)

机构地区：[1]中国石油化工股份有限公司华东油气分公司勘探开发研究院,江苏扬州225007

出　　处：《非常规油气》2025年第2期82-88,共7页Unconventional Oil & Gas

摘　　要：为了提高煤层CH_(4)的采收率,模拟CO_(2)或N_(2)驱替开采煤层中CH_(4)的过程,开展了地层条件下煤对CH_(4),CO_(2)和N_(2)单组分气体的吸附实验、对CH_(4)/N_(2)和CH_(4)/CO_(2)混合气体的竞争吸附实验以及驱替CH_(4)实验。结果表明:当煤吸附单组分气体时,在吸附初期,3种气体的吸附量随着压力的增加迅速增大。在实验压力超过4 MPa以后,N_(2)和CH_(4)的吸附量随压力的增加逐渐变缓并趋于稳定;CO_(2)的吸附量在临界压力(p=7.38 MPa)附近时表现出明显的波动且吸附未达到稳定。N_(2)在解吸时滞后效应不明显,CH_(4)存在一定程度的解吸滞后效应,CO_(2)解吸滞后效应显著,说明CH_(4)和CO_(2)更难从煤的表面解吸。煤对CH_(4)/CO_(2)混合气吸附时,对CO_(2)的吸附速率远大于对CH_(4)的吸附速率;煤对CH_(4)/N_(2)混合气吸附时,对CH_(4)的吸附速率远大于对N_(2)的吸附速率。煤对混合气体的吸附-解吸同样具有解吸滞后效应,产生滞后回环的原因与煤对单组分气体吸附-解吸滞后效应相一致。N_(2)和CO_(2)均可有效地驱替煤中的CH_(4),但是CO_(2)的驱替效率优于N_(2),采用CO_(2)驱替煤中CH_(4)的效果更加显著。In order to improve the recovery of CH_(4) in coal,the displacement process of CH_(4) in coal was simulated by CO_(2) or N_2,and experiments on the adsorption of single component gases,such as CH_4,CO_(2) and N_2,the competitive adsorption experiments on CH_4/N_(2) and CH_4/CO_(2) mixture gases,as well as the CH_(4) displacement experiment,were conducted in coal under geological conditions.The results show that the adsorption capacity of the three gases rapidly increases with the rise of pressure in the initial stage of adsorption when coal adsorbs single component gases.The adsorption capacity of N_(2) or CH_(4 )gradually slows down and stabilizes with the increase of pressure after the pressure exceeds 4 MPa.The adsorption capacity of CO_(2) shows significant fluctuations near the critical pressure(p=7.38 MPa),and the adsorption has not reached stability.The hysteresis effect of N_(2) during desorption is not significant,CH_(4) has a certain degree of desorption hysteresis effect,and CO_(2) has a significant desorption hysteresis effect;so CH_(4) and CO_(2) are more difficult to desorb from the surface of coal than N_2.The adsorption rate of CO_(2) is much higher than that of CH_(4) when coal adsorbs CH_4/CO_(2) mixture;the adsorption rate of CH_(4) is much higher than that of N_(2) when coal adsorbs CH_4/N_(2) mixture.The adsorption of coal on mixed gases also has adsorption-desorption hysteresis,and the reason for the hysteresis loop is consistent with the hysteresis effect of coal on the adsorption-desorption of single component gases.Both N_(2) and CO_(2) can effectively replace CH_(4) in coal,but the displacement efficiency of CO_(2) is better than that of N_2,and the effect of CO_2-replacing-CH_(4) in coal is more significant.

关 键 词：CO_(2)驱替 N_(2)驱替 煤 吸附量 竞争吸附 

分 类 号：TE135[石油与天然气工程—油气勘探]