摘要
目的针对煤储层非均质性较强,不同宏观煤岩组分由于物质成分和孔隙结构差异导致煤层气吸附解吸性能和气水运移特征迥异的问题,方法以黄陇煤田彬长矿区延安组低阶煤为研究对象,采集并分离镜煤和暗煤组分,综合运用显微组分测定、元素分析、压汞、低温液氮吸附、吸附解吸试验等测试方法,研究低阶镜煤和暗煤的孔隙发育特征差异和对甲烷吸附/解吸性能的影响。结果结果表明:(1)镜煤的镜质组质量分数、挥发分及H,O,N,S元素质量分数高于暗煤的,而惰质组、壳质组、矿物、灰分、固定碳和C元素质量分数低于暗煤的。(2)煤样孔隙度为2.92%~10.29%,总体孔隙较发育,暗煤孔隙度略高于镜煤的,孔喉更粗,大孔更发育,连通性更好。镜煤BET比表面积和BJH总孔容均略大于暗煤的,微孔更发育,且多以半封闭型和墨水瓶型孔隙为主。(3)镜煤微小孔更发育,比表面积更大,吸附能力更强。结论煤中甲烷吸附/解吸过程普遍存在解吸滞后现象,暗煤孔隙连通性相对较好,解吸滞后程度低于镜煤的,理论解吸效率高于镜煤的。研究结果可为彬长矿区低阶煤煤层气储层物性认识提供参考。
Objectives The heterogeneity of coal reservoirs is strong,and the differences in material composi⁃tion and pore structure among different macrolithotypes lead to significant differences in the adsorption and desorption performance of coalbed methane and the characteristics of gas-water migration.Methods Taking the Yan’an Formation low rank coal in the Binchang mining area of Huanglong Coalfield as the research ob⁃ject,the components of vitrinite and dark coal were collected and separated.Comprehensive testing methods such as microscopic component determination,elemental analysis,mercury intrusion,low-temperature liquid nitrogen adsorption,and adsorption desorption experiments were used to study the differences in porosity de⁃velopment characteristics of low rank vitrinite and dark coal and their impact on methane adsorption/desorp⁃tion performance.Results The results showed,(1)The mass fraction of vitrinite,volatile matter and H,O,N and S elements of vitrain were higher than those of durain,while the mass fractions of inertinite,chitinite,minerals,ash,fixed carbon and C elements were lower than those of durain;(2)The porosity of the coal sample was 2.92%~10.29%,and the overall pores were relatively developed.The porosity of durain was slightly higher than that of vitrain.The porosity of durain was slightly higher than that of vitrinite,with thicker pore throats,more developed macropores,and better connectivity.The BET specific surface area and BJH total pore volume of vitrain coal were slightly larger than durain,and the micropores were more devel⁃oped,mainly consisting of semi-closed and ink bottle shaped pores;(3)Mirror coal had more developed mi⁃cro pores,larger specific surface area,and stronger adsorption capacity.Conclusions The methane adsorp⁃tion/desorption process in coal generally exhibits desorption hysteresis,with relatively good pore connectiv⁃ity in dark coal.The degree of desorption hysteresis was lower than that of vitrinite,and the theoretical de⁃sorption efficiency was higher than that of vitrinite.The research results can provide reference for under⁃standing the physical properties of low rank coalbed methane reservoirs in Binchang mining area.
作者
李卫波
李菲
史利燕
周少伟
马东民
王传涛
陈跃
LI Weibo;LI Fei;SHI Liyan;ZHOU Shaowei;MA Dongmin;WANG Chuantao;CHEN Yue(Shaanxi Geological Science and Technology Center,Xi’an 710054,Shaanxi,China;College of Geology and Environment,Xi’an University of Science and Technology,Xi’an 710054,Shaanxi,China;School of Chemistry and Chemical Engineering,Yan’an University,Yan’an 716000,Shaanxi,China)
出处
《河南理工大学学报（自然科学版）》
CAS
北大核心
2024年第2期57-67,共11页
Journal of Henan Polytechnic University（Natural Science）
基金
国家自然科学基金资助项目(41902175)
陕西省地勘基金公益性项目(2019JQ-245)。
关键词
黄陇煤田
低煤阶
煤岩组分
孔隙结构
吸附解吸
Huanglong Coalfield
low coal-rank
coal lithotype
pore structure
adsorption/desorption
