摘要
为研究高阶煤中煤体结构和宏观煤岩类型对煤体吸附、解吸的影响,收集了沁水盆地南部3号煤层55口煤层气井的79个煤岩样品的煤岩、煤质、等温吸附及解吸资料,对比研究了相同宏观煤岩类型、不同煤体结构煤样和相同煤体结构、不同宏观煤岩类型煤样的兰氏体积(VL)、兰氏压力(PL)、解吸率和解吸速率等的变化规律,探讨了煤体结构和宏观煤岩类型对煤体吸附、解吸的影响机理。研究结果表明:研究区煤样的VL平均为37.00 m^(3)/t,其中86.61%煤样VL分布在33.00~41.00 m^(3)/t,PL平均为2.82 MPa,其中82.28%煤样PL分布在2.30~3.30 MPa;碎裂煤的吸附、解吸能力均优于原生结构煤,由构造破坏引起的孔隙连通性的差异是导致原生结构煤和碎裂煤解吸、吸附特征差异的根本原因;原生结构煤与碎裂煤的孔裂隙发育程度不同,碎裂煤因孔隙更发育导致其破碎后的甲烷放散效果好于原生结构煤;煤吸附甲烷时表面自由能降低值规律为糜棱煤>碎粒煤>碎裂煤>原生结构煤,反映了不同煤体结构煤吸附甲烷能力的差异;3种宏观煤岩类型煤的吸附能力和解吸能力均表现为光亮煤>半亮煤>半暗煤,一方面是由煤的比表面积大致按照光亮煤、半亮煤和半暗煤的顺序逐渐减小反映的煤基质表面吸附点位差异所致,另一方面是由于镜煤与暗煤中镜质组和惰质组含量的差异所引起。研究旨在进一步揭示高阶煤储层煤层气赋存、产出机理,为煤层气有利区及目标层位优选提供依据。
In order to study the influence of coal body structure and macrolithotype of coal in high rank coal on coal body adsorption and desorption, The data of coal petrography, coal quality, isothermal adsorption and desorption of 79 coal rock samples from 55 coal-bed methane wells in No.3 Coal Seam in the south of Qinshui Basin were collected, and the change laws in the Langmuir volume(VL), Langmuir pressure(PL), desorption rate of coal samples with the same macrolithotype of coal, different coal body structures and the same coal body structure, different macrolithotype of coal of coal samples, were discussed in the influential mechanisms of coal body structure and macrolithotype of coal on coal body adsorption and desorption. The results show that the average VLof coal samples in the study area is37.00 m^(3)/t, of which 86.61% is distributed in 33.00—41.00 m^(3)/t, and the average PL is 2.82 MPa, of which 82.28% is distributed in2.30~3.30 MPa. The adsorption and desorption capacities of fractured coal are better than those of primary structure coal and the difference of pore connectivity caused by structural destruction is the fundamental reason for the difference of desorption and adsorption characteristics between primary structural coal and fractured coal;The development degree of pores and fissures of primary structure coal is different from that of fractured coal. The methane emission effect of fractured coal is better than that of primary structure coal because of more developed pores. The decreasing rule of surface free energy of coal for methane adsorption is the mylonitic coal > granulitic coal >fractured coal > primary structure coal, which reflects the difference of methane adsorption capacity of coal with different coal structure;the adsorption and desorption capabilities of the three types of macro coals are bright coal > semibright coal > semidull coal. On the one hand, the specific surface area of coal decreases roughly in the order of bright coal, semibright coal, and semidull coal, which reflects th
作者
赵方钰
邓泽
王海超
王泽
孙丕臣
杨胜博
ZHAO Fangyu;DENG Ze;WANG Haichao;WANG Ze;SUN Pichen;YANG Shengbo(Xinjiang Key Laboratory for Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt,Urumqi 830017,China;School of Geological and Mining Engineering,Xinjiang University,Urumqi 830017,China;CBM Engineering Technology Research Center,Xinjiang University,Urumqi 830017,China;Key Laboratory of Unconventional Oil and Gas,China National Petroleum Corporation,Langfang 065000,China)
出处
《煤炭科学技术》
CAS
CSCD
北大核心
2022年第12期170-184,共15页
Coal Science and Technology
基金
国家自然科学基金资助项目(41902171)
新疆维吾尔自治区自然科学基金资助项目(2018D01C050)
新疆维吾尔自治区天山青年计划资助项目(2020Q065)。
关键词
煤层气
煤体结构
宏观煤岩类型
吸附
解吸
coalbed methane
coal body structure
macrolithotype of coal
adsorption
desorption
