摘要
页岩储层普遍含水,水分对页岩气体吸附行为和地质储量评估具有显著影响。为探究水分对页岩吸附行为的影响规律,构建了考虑含水率影响的吸附模型,结合多组试验数据对新建模型的合理性进行验证,并进一步剖析了含水页岩的吸附行为。在此基础上,讨论了不同吸附机制对页岩中甲烷等温吸附的贡献,并通过热力学参数对比了干湿页岩中吸附热力学特性。结果表明:在气体压力变化过程中,甲烷气体吸附量呈典型的“三段式”变化。其中,水分对甲烷吸附量具有抑制作用,含水页岩吸附量显著低于干燥页岩,页岩吸附量随含水率的增大呈降低趋势。此外,温度同样对甲烷吸附具有抑制作用,当含水率恒定时,随温度升高页岩吸附能力呈降低趋势。同时,不同吸附机制对吸附量的贡献受到水分和压力的共同影响,压力和含水率越高,微孔填充吸附量对总吸附量的贡献率越低。热力学参数表明干燥页岩与含水页岩的甲烷吸附均为物理吸附,同一吸附量下,干燥页岩等量吸附热始终高于含水页岩。水分通过改变页岩非均一性占据高能吸附位点同时影响分子间作用力,综合作用下使得等量吸附热降低,进而导致含水页岩吸附能力降低。研究结果有助于页岩吸附气量的准确计算,并为页岩气藏开发方案和编制提供理论依据。
Shale reservoirs generally contain water that has a significant impact on shale gas adsorption behavior and geological reserve evaluation.In order to explore the influence of water content on gas adsorption behavior in shale,an adsorption model considering the influence of water content was established,the rationality of the new model was verified by combining several sets of experimental data,and gas adsorption behavior in water-bearing shale was further analyzed.On this basis,the contribution of different adsorption mechanisms to the isothermal adsorption of methane in shale was discussed,and the thermodynamic characteristics of adsorption in dry and wet shale were compared by thermodynamic parameters.The results shown that,the methane adsorption amount shown a typical“three-stage”change in the process of gas pressure change.Among them,water has an inhibitory effect on methane adsorption capacity,gas adsorption capacity in water-bearing shale was significantly lower than that in dry shale,and gas adsorption capacity decreased with the increasing water content.In addition,temperature also inhibited methane adsorption,and gas adsorption capacity in shale decreased with the increas-ing temperature when the water content was constant.At the same time,the contribution of different adsorption mechanisms to adsorption capacity was affected by the combination of water and pressure.The higher the pressure and water content,the lower the contribution of microporous filled adsorption to the total adsorption capacity.Thermodynamic parameters indicated that methane adsorption in both dry and water-bearing shale was physical adsorption,and the isosteric adsorption heat in dry shale was always higher than that in water-bear-ing shale under the same adsorption capacity.Water occupied high-energy adsorption sites and affected intermolecular forces by altering shale heterogeneity,which combined to reduce isosteric adsorption heat and hence gas adsorption capacity in water-bearing shale.The re-search results contributed to th
作者
杨竣淞
李波波
李建华
高政
宋浩晟
段淑蕾
YANG Junsong;LI Bobo;LI Jianhua;GAO Zheng;SONG Haosheng;DUAN Shulei(College of Mining,Guizhou University,Guiyang 550025,China;The National Joint Engineering Laboratory for the Utilization of Dominant Mineral Resources in Karst Area,Guizhou University,Guiyang 550025,China;Guizhou Key Laboratory of Comprehensive Utilization of Non-metallic Mineral Resources,Guiyang 550025,China)
出处
《煤炭科学技术》
EI
CAS
CSCD
北大核心
2024年第3期95-105,共11页
Coal Science and Technology
基金
贵州省省级科技计划资助项目(黔科合基础−ZK[2021]重点052)
国家自然科学基金资助项目(52274183,52064007)。
关键词
含水页岩
吸附模型
甲烷吸附量
多重吸附机制
热力学
water-bearing shale
adsorption model
methane adsorption capacity
multiple adsorption mechanism
thermodynamics
