Experimental study on selective adsorption/desorption of CO2 and CH4 behavior on shale under high pressure condition
Experimental study on selective adsorption/desorption of CO2 and CH4 behavior on shale under high pressure condition
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高压条件下页岩选择性吸附/解吸CO2和CH4行为实验研究
DOI：
10.1021/acs.energyfuels.8b02068
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发表时间：
2018
期刊：
影响因子：
5.3
通讯作者：
Juan Zhang
中科院分区：
文献类型：
--
作者：
Zihao Yang;Zhaoxia Dong;Liu Wang;Taiheng Yin;Xinyu Fan;Meiqin Lin;Juan Zhang
CO2强化煤层气的作用机理已被许多研究者所探讨。CO2和甲烷在煤表面的竞争吸附被认为是主导作用。然而，注CO2能否提高页岩气采收率目前还没有很好的答案。CO2、甲烷及其混合气体在页岩上的吸附和解吸行为研究较少。为了评价利用CO2提高页岩气采收率的可行性，采用测压法，在50 °C、5.0 MPa压力下，对柴达木盆地页岩进行了甲烷、二氧化碳及其混合气体的吸附和解吸实验。结果表明，对于单一组分CO2或甲烷，页岩对CO2具有优先吸附作用。同时，两种气体混合物的吸附行为表明，页岩优先吸附CH4，而不是CO2，说明在吸附过程中，CO2的存在促进了CH4的吸附。对于解吸过程，则出现了相反的现象，即随着压力的降低，CO2在页岩上表现出更强的吸附能力。在此期间，CO2的存在促进了CH4的解吸，这可能导致页岩气的更高采收率。竞争吸附实验结果表明，利用CO2提高页岩气采收率在理论上是可行的。
The mechanisms of CO2enhancing coal bed methane are investigated by many works. The competitive adsorption of CO2and methane on coal is believed to be the dominant effect. However, whether CO2injection can be used for improving shale gas recovery is not yet well answered. The adsorption and desorption behaviors of CO2, methane, or their mixture on shale are seldom reported. To evaluate the feasibility of the utilization of CO2to enhance shale gas recovery, adsorption and desorption experiments of methane, carbon dioxide, and mixtures of the two gases on shales from the Qaidam basin have been operated by the manometric method at 50 °C and pressures up to 5.0 MPa. The results show that, for a single component of CO2or methane, preferential adsorption of CO2on shale is observed. Meanwhile, the adsorption behavior of mixtures of the two gases manifests that CH4is preferentially adsorbed on shale, instead of CO2, which means that, during the adsorption process, the existence of CO2promoted the sorption of CH4. For the process of desorption, an opposite phenomenon is obtained, it is presented that, with the pressure decreasing, CO2shows a higher adsorption ability on shale. During this period, the existence of CO2facilitates desorption of CH4, which may result in a higher recovery of shale gas. On the basis of the competitive adsorption experimental results, the utilization of CO2to improve shale gas recovery is practicable theoretically.