宁东煤田石炭−二叠系富油煤赋存的地质控制作用  

Geological factors controlling the occurrence of Carboniferous-Permian tar-rich coals in the Ningdong coalfield

作　　者：黄鹏程 郭伟勇 姬晓燕 蔡飞飞 张志峰[1,2,3] 黄康 程云强 刘争 王贝 陈蓉 师庆民 HUANG Pengcheng;GUO Weiyong;JI Xiaoyan;CAI Feifei;ZHANG Zhifeng;HUANG Kang;CHENG Yunqiang;LIU Zheng;WANG Bei;CHEN Rong;SHI Qingmin(Institute of Geological Survey,China University of Geosciences,Wuhan 430074,China;Ningxia Hui Autonomous Region Bureau of Coal Geology,Yinchuan 750002,China;Ningxia Unconventional Natural Gas Exploration and Development Innovation Team,Yinchuan 750002,China;College of Geology and Environment,Xi’an University of Science and Technology,Xi’an 710054,China)

机构地区：[1]中国地质大学(武汉)地质调查研究院,湖北武汉430074 [2]宁夏回族自治区煤炭地质局,宁夏银川750002 [3]宁夏非常规天然气勘查开发创新团队,宁夏银川750002 [4]西安科技大学地质与环境学院,陕西西安710054

出　　处：《煤田地质与勘探》2024年第7期119-131,共13页Coal Geology & Exploration

基　　金：宁夏自然科学基金优秀青年项目(2022AAC05064);宁夏重点研发计划项目(2023BEG02058);宁夏地质事业发展专项资金项目(640000223000000016748)。

摘　　要：【目的】鄂尔多斯盆地宁东煤田蕴藏丰富的富油煤资源,其中石炭−二叠系煤层由于热演化及沉积环境差异导致富油煤赋存较为特殊。【方法】以红墩子矿区和四股泉矿区煤为研究对象,在分析富油煤赋存特点及关键物质组成基础上,探讨了煤化程度与沉积环境对煤焦油产率的控制作用。【结果与结论】结果表明:宁东煤田石炭−二叠系煤层焦油产率平均值介于7.15%~11.07%,但不同区域、不同煤层及同煤层不同部位焦油产率普遍存在差异性。煤化程度是影响研究区富油煤赋存的核心地质控制因素,使得煤焦油产率随煤化程度升高呈现先增加后降低的变化趋势,峰值转折点为C_(daf)=84%。煤化作用控制下,H/C、O/C与焦油产率之间呈现相近的演化趋势,同时造成活性组分(镜质组+壳质组)仅在C_(daf)<84%时与焦油产率呈良好正相关性。成煤母质、气候条件和水体古盐度对煤焦油产率影响较小,但水体还原性及水动力条件间接影响了同煤级煤焦油产率的离散性。镜惰比(V/I)、凝胶化指数(GI)、灰成分指数(K)、U/Th及δU指示的成煤环境表现出覆水性深、闭塞潮湿、还原性强、木本组织少,有利于形成高焦油产率的富油煤;灰分产率、SiO_(2)+Al_(2)O_(3)等指示水动力条件强、陆源碎屑输入量大,不利于高焦油产率富油煤形成。[Objective]The Ningdong Coalfield of the Ordos Basin boasts abundant tar-rich coal resources,of which tarrich coals in the Carboniferous-Permian coal seams exhibit unique occurrence characteristics due to differences in thermal evolution and sedimentary environments.[Methods]This study analyzed the occurrence characteristics and critical material composition of tar-rich coals in the Hongdunzi and Siguquan mining areas.Based on this,it explored the controlling effects of the degree of coalification and sedimentary environment on the tar yield.[Results and Conclusions]The results indicate that the Carboniferous-Permian coal seams in the Ningdong Coalfield exhibit average tar yields ranging from 7.15%to 11.07%,which generally vary in different zones,different coal seams,and even different parts of the same coal seam.The degree of coalification is identified as a core geologic factor controlling the occurrence of tar-rich coals in the study area.With an increase in the degree of coalification,the tar yield trended upward initially and then downward,peaking at C_(daf)=84%.Under the action of coalification,a similar evolutionary trend can be observed between the H/C and O/C ratios and the tar yield.Meanwhile,there were significant positive correlations between active components(i.e.,vitrinite and exinite)and the tar yield merely under C_(daf)<84%.Coal-forming parent materials,climatic conditions,and paleosalinity of water bodies exert minor impacts on the tar yield.In contrast,the reducibility and hydrodynamic conditions of water bodies indirectly affect the discreteness of the tar yield of coals at the same ranks.The vitrinite/inertinite ratio(V/I),gelification index(GI),ash composition index(K),U/Th ratio,andδU values indicate that coal-forming environment features deep water,occlusion,moisture,strong reducibility,and small quantities of woody tissues,which are conducive to the formation of tar-rich coals with a high tar yield.In contrast,indices such as ash yield and SiO_(2)+Al_(2)O_(3) indicate strong hydrodynamic

关 键 词：富油煤 焦油产率 煤化程度 成煤环境 石炭−二叠系 宁东煤田 

分 类 号：P618.11[天文地球—矿床学]