不同环境成因腐殖煤生气潜力差异的模拟实验研究
发布时间：2018-08-13 16:53
【摘要】：鄂尔多斯盆地上古生界发育不同环境条件下形成的腐殖煤,本文在对上石炭-下二叠统煤系烃源岩地球化学特征详细研究的基础上,采用有机地球化学和有机岩石学相结合、实验样品生烃潜力评价与生烃模拟实验相结合的研究方法,研究盆地内不同沉积环境形成的腐殖煤生烃潜力的差异及造成这种差异的主要地球化学原因,主要取得了如下研究成果和认识：1、鄂尔多斯上古生界成煤的地质环境具有多样化的特点。既有受海水作用影响的泥炭坪成煤环境,也有在三角洲沉积体系中的陆相沼泽成煤环境。环境条件的差异造成了有机质来源的不同。2、研究表明,研究区域内成煤环境的差异可以用饱和烃化合物中的Pr/Ph、 Pr/nC17- Ph/nC18关系图版、芳烃化合物中的“三芴”系列组成加以描述。这一特征也为模拟实验样品的选取提供了重要的参考依据。3、选择成熟度相似,不同Pr/Ph值的腐殖煤进行生烃量的黄金管模拟实验研究。结果表明,对相同层位的腐殖煤而言,Pr/Ph值较低者通常具有相对较高的生烃演化潜力,说明沉积环境对于腐殖煤的生烃演化潜力具有重要影响。模拟实验得到的产气率图版特征表明,在模拟温度350℃-525℃(相当于Ro从1.00-2.30%)范围内,烃气重量总产率呈现一个明显的“鼓包”,这主要体现了腐殖煤中可溶有机质在成熟度较高情况下裂解成为气态烃的过程。对比同一样品在350℃-525℃温阶范围和525℃-650℃温阶范围的生气率曲线可知,相比于固体有机质(千酪根),腐殖煤中可溶有机质对生气的贡献往往不可忽视。4、对比研究表明,不同环境形成的腐殖煤,其“壳质组+腐泥组”的含量特征并不明显,而主要差别体现在富氢镜质组(特别是基质镜质体)的生烃贡献上。研究显示,基质镜质体中所含的超微类脂体的生烃作用,应当是不同成煤环境形成腐殖煤生烃潜力差异的主要原因。5、研究区域内部分Pr/Ph值较低腐殖煤的可溶有机质中能够检测出代表细菌生源产物的一系列单甲基化合物,而显微组分定量检测结果中,低等生源贡献极低,仅见有少量的藻类体B和矿物沥青基质。这些样品往往具有较高的有机质降解率和氢指数。由此推断,在强还原性沉积条件下,以高等植物作为碳源的化能异样型微生物(细菌、真菌、原生动物)大量存在。在生物化学作用阶段,微生物对高等植物的改造作用一方面会降解和消耗一部分高等植物有机质同时消耗大量的氧,从而改善有机质的保存条件；另一方面这些生物有机质本身富氢程度较高,在其死亡进而进入地层后,会导致煤系有机质富氢程度增加。
[Abstract]:Humic coal formed in the Upper Paleozoic in Ordos Basin is formed under different environmental conditions. Based on the detailed study of the geochemical characteristics of the source rocks of the Upper Carboniferous and Lower Permian coal measures, organic geochemistry and organic petrology are adopted in this paper. This paper studies the difference of hydrocarbon generation potential of humic coal formed in different sedimentary environments in the basin and the main geochemical reasons for the difference in hydrocarbon generation potential evaluation of experimental samples combined with hydrocarbon-generating simulation experiment. The main achievements and understanding are as follows: 1. The geological environment of Upper Paleozoic coal forming in Ordos is diversified. There are not only peat plateau coal forming environment affected by seawater, but also continental marsh coal forming environment in delta sedimentary system. The difference of environmental conditions leads to different sources of organic matter. The study shows that the difference of coal-forming environment in the study area can be described by Pr-P / Phin, Pr-nC17- Ph/nC18 relation in saturated hydrocarbon compounds, and the "trifluorene" series composition in aromatic compounds. This feature also provides an important reference basis for the selection of simulated experimental samples. The selection maturity of humic coal with different Pr/Ph values is similar to that of gold tube simulation. The results show that the lower PRP / Ph values of humic coals at the same horizon usually have relatively high hydrocarbon generation potential, indicating that the sedimentary environment has an important influence on the hydrocarbon generation evolution potential of humic coals. The characteristics of the gas yield chart obtained from the simulation experiments show that in the range of 350 鈩，
本文编号：2181599
[Abstract]:Humic coal formed in the Upper Paleozoic in Ordos Basin is formed under different environmental conditions. Based on the detailed study of the geochemical characteristics of the source rocks of the Upper Carboniferous and Lower Permian coal measures, organic geochemistry and organic petrology are adopted in this paper. This paper studies the difference of hydrocarbon generation potential of humic coal formed in different sedimentary environments in the basin and the main geochemical reasons for the difference in hydrocarbon generation potential evaluation of experimental samples combined with hydrocarbon-generating simulation experiment. The main achievements and understanding are as follows: 1. The geological environment of Upper Paleozoic coal forming in Ordos is diversified. There are not only peat plateau coal forming environment affected by seawater, but also continental marsh coal forming environment in delta sedimentary system. The difference of environmental conditions leads to different sources of organic matter. The study shows that the difference of coal-forming environment in the study area can be described by Pr-P / Phin, Pr-nC17- Ph/nC18 relation in saturated hydrocarbon compounds, and the "trifluorene" series composition in aromatic compounds. This feature also provides an important reference basis for the selection of simulated experimental samples. The selection maturity of humic coal with different Pr/Ph values is similar to that of gold tube simulation. The results show that the lower PRP / Ph values of humic coals at the same horizon usually have relatively high hydrocarbon generation potential, indicating that the sedimentary environment has an important influence on the hydrocarbon generation evolution potential of humic coals. The characteristics of the gas yield chart obtained from the simulation experiments show that in the range of 350 鈩，
本文编号：2181599
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