摘要
选取四川宜宾地区志留系龙马溪组页岩,对总有机碳、黏土矿物含量等储层性质进行表征。利用扫描电镜、高压压汞法、低温氮气吸附一解吸法和二氧化碳气体吸附法对孔隙结构特征进行定性和定量分析。采用质量法对页岩样品进行不同温度时的等温吸附和解吸实验,结合吸附势理论对吸附解吸过程进行解释。结果表明,页岩样品TOC较高,页岩样品主要以微孔为主,介孔次之,大孔发育较少;微孔和介孔的发育增大了页岩的表面积,提供了更多的吸附位,有利于页岩气的吸附。页岩样品等温吸附曲线表明,随着压力的增大,吸附量先迅速增大而后逐渐趋于稳定,解吸曲线与吸附曲线相似并存在滞后现象;TOC与页岩吸附性能有着较好的正相关性;吸附势能曲线中势能零点与吸附曲线的拐点基本一致,通过吸附势的变化可以解释吸附解吸过程中页岩气的赋存状态。
Shales of the Silurian Longmaxi Formation in the Yibin Region,Sichuan,were investigated and their geological parameters,including total organic carbon(TOC)contents and clay mineral contents,were measured.Scanning electron microscopy,high pressure mercury injection,low temperature nitrogen adsorption-desorption,and carbon dioxide gas adsorption methods were employed to qualitatively and quantitatively analyze pore structure characteristics.The mass method was utilized to conduct isothermal adsorption and desorption experiments on shale samples at different temperatures and adsorption and desorption processes were explained using the adsorption potential theory.The results demonstrate that these shale samples have relatively high TOC contents,and pore structures are dominated by micropores,followed by mesopores and macropores.Connected micropores and mesopores increase surface areas of shales,and provide more adsorption spaces,thus facilitating adsorption of shale gas.The isothermal adsorption curves of the shale samples reveal that as the pressure increases,the adsorption volume increases rapidly at first and then levels off gradually.The desorption curves resemble the adsorption ones,but show some delays.The TOC contents indicate relatively good positive correlations with the adsorption performances of shales.The zero-potential point of the absorption potential curve is generally consistent with the turning point of the adsorption curve.The occurrence of shale gas during adsorption and desorption can be explained by variations in adsorption potentials.
作者
岳长涛
李术元
许心怡
马跃
杨飞
YUE Changtao;LI Shuyuan;XU Xinyi;MA Yue;YANG Fei(College of Science,China University of Petroleum(Beijing),Changping,Beijing 102249,China)
出处
《西南石油大学学报（自然科学版）》
CAS
CSCD
北大核心
2018年第5期84-94,共11页
Journal of Southwest Petroleum University(Science & Technology Edition)
基金
国家自然科学基金(41372152)
关键词
页岩气
微孔特征
等温吸附
等温解吸
吸附势
shale gas
micropore characteristic
isothermal adsorption
isothermal desorption
adsorption potential
