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。

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、SiO₂+Al₂O₃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。

The Ningdong Coalfield of the Ordos Basin boasts abundant tar-rich coal resources, of which tar-rich coals in the Carboniferous-Permian coal seams exhibit unique occurrence characteristics due to differences in thermal evolution and sedimentary environments.

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.

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, and δU 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 SiO₂+Al₂O₃ indicate strong hydrodynamic conditions and substantial quantities of terrigenous clast inputs, which are unfavorable for the formation of tar-rich coals with a high tar yield.