【摘要】：鄂爾多斯盆地上古生界發(fā)育不同環(huán)境條件下形成的腐殖煤,本文在對上石炭-下二疊統(tǒng)煤系烴源巖地球化學(xué)特征詳細(xì)研究的基礎(chǔ)上,采用有機(jī)地球化學(xué)和有機(jī)巖石學(xué)相結(jié)合、實驗樣品生烴潛力評價與生烴模擬實驗相結(jié)合的研究方法,研究盆地內(nèi)不同沉積環(huán)境形成的腐殖煤生烴潛力的差異及造成這種差異的主要地球化學(xué)原因,主要取得了如下研究成果和認(rèn)識：1、鄂爾多斯上古生界成煤的地質(zhì)環(huán)境具有多樣化的特點。既有受海水作用影響的泥炭坪成煤環(huán)境,也有在三角洲沉積體系中的陸相沼澤成煤環(huán)境。環(huán)境條件的差異造成了有機(jī)質(zhì)來源的不同。2、研究表明,研究區(qū)域內(nèi)成煤環(huán)境的差異可以用飽和烴化合物中的Pr/Ph、 Pr/nC17- Ph/nC18關(guān)系圖版、芳烴化合物中的“三芴”系列組成加以描述。這一特征也為模擬實驗樣品的選取提供了重要的參考依據(jù)。3、選擇成熟度相似,不同Pr/Ph值的腐殖煤進(jìn)行生烴量的黃金管模擬實驗研究。結(jié)果表明,對相同層位的腐殖煤而言,Pr/Ph值較低者通常具有相對較高的生烴演化潛力,說明沉積環(huán)境對于腐殖煤的生烴演化潛力具有重要影響。模擬實驗得到的產(chǎn)氣率圖版特征表明,在模擬溫度350℃-525℃(相當(dāng)于Ro從1.00-2.30%)范圍內(nèi),烴氣重量總產(chǎn)率呈現(xiàn)一個明顯的“鼓包”,這主要體現(xiàn)了腐殖煤中可溶有機(jī)質(zhì)在成熟度較高情況下裂解成為氣態(tài)烴的過程。對比同一樣品在350℃-525℃溫階范圍和525℃-650℃溫階范圍的生氣率曲線可知,相比于固體有機(jī)質(zhì)(千酪根),腐殖煤中可溶有機(jī)質(zhì)對生氣的貢獻(xiàn)往往不可忽視。4、對比研究表明,不同環(huán)境形成的腐殖煤,其“殼質(zhì)組+腐泥組”的含量特征并不明顯,而主要差別體現(xiàn)在富氫鏡質(zhì)組(特別是基質(zhì)鏡質(zhì)體)的生烴貢獻(xiàn)上。研究顯示,基質(zhì)鏡質(zhì)體中所含的超微類脂體的生烴作用,應(yīng)當(dāng)是不同成煤環(huán)境形成腐殖煤生烴潛力差異的主要原因。5、研究區(qū)域內(nèi)部分Pr/Ph值較低腐殖煤的可溶有機(jī)質(zhì)中能夠檢測出代表細(xì)菌生源產(chǎn)物的一系列單甲基化合物,而顯微組分定量檢測結(jié)果中,低等生源貢獻(xiàn)極低,僅見有少量的藻類體B和礦物瀝青基質(zhì)。這些樣品往往具有較高的有機(jī)質(zhì)降解率和氫指數(shù)。由此推斷,在強(qiáng)還原性沉積條件下,以高等植物作為碳源的化能異樣型微生物(細(xì)菌、真菌、原生動物)大量存在。在生物化學(xué)作用階段,微生物對高等植物的改造作用一方面會降解和消耗一部分高等植物有機(jī)質(zhì)同時消耗大量的氧,從而改善有機(jī)質(zhì)的保存條件；另一方面這些生物有機(jī)質(zhì)本身富氫程度較高,在其死亡進(jìn)而進(jìn)入地層后,會導(dǎo)致煤系有機(jī)質(zhì)富氫程度增加。
[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，

本文編號：2181599