考虑页岩多重吸附机制的超临界甲烷等温吸附模型  

Supercritical methane isothermal adsorption model considering multiple adsorption mechanisms in shale

作　　者：刘香禺 张烈辉[1] 李树新 张介辉 赵玉龙[1] 张芮菡[1] 郭晶晶[1] 唐慧莹 张帆[1] Liu Xiangyu;Zhang Liehui;Li Shuxin;Zhang Jiehui;Zhao Yulong;Zhang Ruihan;Guo Jingjing;Tang Huiying;Zhang Fan(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Sichuan Chengdu610500,China;PetroChina Coalbed Methane Company Limited,Beijing100028,China;PetroChina Zhejiang Oilfield Company,Zhejiang Hangzhou 311100,China)

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500 [2]中国石油煤层气有限责任公司,北京100028 [3]中国石油浙江油田公司,浙江杭州311100

出　　处：《石油学报》2022年第10期1487-1499,共13页Acta Petrolei Sinica

基　　金：国家自然科学基金项目(No.52222402,No.52074235,No.51874251,No.52004237);四川省杰出青年科技人才项目(2022JDJQ0009);中国石油-西南石油大学创新联合体项目(2020CX020202,2020CX030202)资助。

摘　　要：页岩中的超临界甲烷等温吸附模型研究对于页岩气藏储量评估、生产动态预测和开发方案编制等具有重要意义。以超临界甲烷等温吸附理论和分子动力学模拟结果为依据,考虑不同尺度空间中吸附机制差异,以Dubinin-Astakhov(DA)微孔充填模型表征微孔中的甲烷分子吸附,以Brunauer-Emmett-Teller(BET)多分子层吸附模型表征中孔和大孔中的甲烷分子吸附,建立了DA-BET超临界甲烷等温吸附模型。在此基础上,结合高温高压实验数据分析了模型拟合方法和拟合效果,讨论了不同吸附机制对页岩中超临界甲烷等温吸附的贡献。研究结果表明:DA-BET超临界甲烷等温吸附模型可以高精度地拟合实验数据,计算出的吸附特征曲线满足唯一性,并且可以利用该模型预测高温条件下页岩吸附甲烷的能力;在低压阶段,甲烷分子以微孔充填吸附为主;温度、压力显著影响不同吸附机制对总吸附量的贡献,温度越低、压力越高,微孔充填吸附量对总吸附量的贡献越小。The research on supercritical methane isothermal adsorption model in shale is of great significance for shale gas reserve assessment,production dynamics prediction and development program preparation.Based on the supercritical methane isothermal adsorption theory and molecular dynamics simulation results,the DA-BET supercritical methane isothermal adsorption model was established considering the differences of adsorption mechanisms in different scale spaces,characterizing the methane molecule adsorption in micropores and mesopores/macropores by use of DA micropore filling model and BET multimolecular layer adsorption model,repectively.On this basis,the model fitting method and fitting effect were analyzed using high temperature and high pressure experimental data,and the contribution of different adsorption mechanisms to supercritical methane isothermal adsorption in shale was also explored.The results show that the DA-BET supercritical methane isothermal adsorption model can highly accurately fit the experimental data,and the adsorption characteristic curves obtained by calculationsatisfy the uniqueness,and the model can be used to predict the methane adsorption capacity of shale at high temperature.In the low-pressure stage,methane molecules are predominantly adsorbed by micropore filling;temperature and pressure significantly affect the contribution of different adsorption mechanisms to the total adsorption;the lower the temperature and the higher the pressure,the smaller the contribution of micropore filling adsorption to the total adsorption capacity.

关 键 词：页岩 超临界甲烷 等温吸附 多重吸附机制 吸附贡献 

分 类 号：TE312[石油与天然气工程—油气田开发工程]