煤田地质与勘探2024，Vol.52Issue(5)：1-11,11.DOI:10.12363/issn.1001-1986.24.01.0035
分形界面吸附行为初探
A preliminary study of coalbed methane adsorption at fractal interfaces
摘要
Abstract
The adsorption and desorption mechanisms of coalbed methane(CBM)are foundational for revealing CBM accumulation mechanisms and achieving efficient CBM exploitation.Studies have indicated that coal reservoirs exhibit complex pore structures with fractal features,significantly influencing CBM adsorption at pore-solid interfaces.Based on a comparative analysis of several common adsorption models for gas-solid interfaces and a summary of their charac-teristics and applicable conditions,this study suggests that all these adsorption models still rely on the stationary assump-tion of adsorption selectivity for the description and application of CBM adsorption behavior at fractal interfaces while overlooking the scale invariance of the adsorption thickness.The fractal topography theory can effectively calibrate the scale invariance of fractal objects,providing theoretical support for the equivalent characterization of fractal interfaces.Hence,in combination with the description of CBM adsorption behavior at gas-solid interfaces in the above models,to-gether with the fractal topography theory,this study proposed related hypotheses and control mechanisms of fractal ad-sorption behavior at pore-solid interfaces in coal reservoirs.Furthermore,it constructed an adsorption topography-based monolayer adsorption model,obtaining adsorption isotherms under different combinations of adsorption topological parameters.The analysis reveals that as the adsorption pressure increased,the adsorption coverage exhibited three dis-tinct growth trends:exponential,linear,and logarithmic,while the adsorption heat displayed a trend of logarithmic de-crease.The results of this study show that different combinations of adsorption topological parameters can yield differ-ent adsorption isotherms,making up for the deficiency that the Langmuir equation can merely describe a single type of adsorption isotherms.To verify the applicability of the model constructed,this study compared the actual adsorption iso-therms with the simulated ones using the liquid nitrogen adsorption data of organic-rich argillaceous shale samples from the Wuxiang block of the Qinshui Basin.The finding indicates that adjusting the combinations of adsorption topological parameters can align the trends of simulated adsorption isotherms with those of actual ones.Finally,this study explored the research direction of the adsorption and desorption mechanisms and proposed the adsorption layer concept through analogy with the electron layer,emphasizing that developing fractal dynamics description models is essential for illumin-ating CBM adsorption and desorption regularities.关键词
煤层气/吸附解吸/分形特征/孔-固界面/孔隙结构/吸附模型Key words
coalbed methane(CBM)/adsorption and desorption/fractal feature/pore-solid interface/pore structure/ad-sorption model分类
矿业与冶金引用本文复制引用
金毅,李娅妮,宋慧波,赵梦余,杨运航,陈泽楠..分形界面吸附行为初探[J].煤田地质与勘探,2024,52(5):1-11,11.基金项目
河南省杰出青年科学基金项目(232300421025) （232300421025）
国家自然科学基金项目(41972175) （41972175）
河南省高校科技创新团队项目(21IRTSTHN007) （21IRTSTHN007）
河南省高校基本科研业务费专项资金项目(NSFRF220204) （NSFRF220204）
