基于煤岩煤质特征的成煤环境分析——以鲁西汶宁煤田新驿煤矿为例

Coal-forming Environment Analysis Based on Coal Lithotype and Coal Quality Features A Case Study of Xinyi Coalmine in Wenning Coalfield,Western Shandong

煤岩煤质是分析含煤岩系沉积环境的重要参数。以鲁西汶宁煤田新驿煤矿为例,采用煤岩学、地球化学和沉积学相结合的方法,通过采样、测试及相关分析手段,发现受到海水影响较弱的山西组煤层的宏观煤岩类型以半亮型-半暗型煤为主,微观煤岩类型以微三合煤为主;而受到海水影响较强的太原组煤层的宏观煤岩类型以半亮煤为主,微观煤岩类型以微镜煤占绝对优势。山西组煤层显微组分中的镜质体以基质镜质体为主,惰质组以火焚丝质体为主,壳质组分以小孢子体和树皮体为主;太原组煤层显微组分均以基质镜质体、均质镜质体为主,惰性组氧化丝质体为主,壳质组以小孢子体为主。煤质特征与成煤环境也表现很大差异性,受海水影响较小的山西组煤层具灰分产率高、挥发分低、全硫含量低等特点;而受海水影响较强的太原组煤层具灰分产率低、挥发分高、全硫含量高等特点。最后发现,全硫含量分布能够反映出海侵特征,即全硫含量分布高的部位代表着区内最初接受海侵地区。

The coal lithotype and coal quality are major parameters in coal -bearing strata sedimentary environment analysis. So, the different environments of coal formation can be discussed through coal lithotype and coal quality analyses. Taking the Xinyi coalmine in Wenning coalfield, western Shandong as example, using integrated coal petrology, geochemistry and sedimentology method, through sampling, testing and related analytic means, have found that the coal seams in the Shanxi Formation because of weakly impacted by sea water made the macrolithotype of coal mainly semibright - semidu11 coal ; while trimacerite predominant in mierolithotype ; in the sea water strongly impacted Taiyuan Formation coal seams macrolithotype mainly semibright coal, microlithotype is the vitrite dominant. In the Shanxi Formation coal macerals, vitrinite is mainly desmocollinite; inertinite mainly pyrofusinite; exinite mainly microsporinite and barkinite. In the Taiyuan Formation coal macerals, vitrinite is mainly desmocollinite and homocollinite; inertinite mainly oxyfusinite; exinite mainly microsporinite. Coal quality features and coal - forming environment also present large differentiation ： sea water weakly impacted Shanxi Formation coals have higher ash content, lower volatile matter and total sulfur content ; while sea water strongly im- pacted Taiyuan Formation coals have lower ash content, higher volatile matter and total sulfur content. Finally, the total sulfur contents distribution can reflect transgression features; the region with high total sulfur content represents initial transgression part. The study has provided certain basis for coal geological exploration and coal exploitation in the area.