Abstract

The hydrocarbon composition of the thermolysis products of asphaltenes from biodegraded oils of the Labagan and Usa oilfields and non-biodegraded oil of the Salyukinskoe oilfield of the Timan–Pechora sedimentary basin has been studied. The IR spectra of the asphaltenes are identical, indicating their similar structural group composition. The thermolysis of the asphaltenes has been carried out in an argon flow successively at 300 and 350°C. It has been shown that desorption of saturated and aromatic components from the pores of the asphaltenes predominantly occurs at 300°C. For the initial biodegraded oils and the oil that did not undergo biochemical oxidation, a number of geochemical parameters calculated in terms of acyclic hydrocarbons (HCs) and polycyclic biomarkers turns out to be similar to those obtained for the thermolysis products of the asphaltenes heated at 350°C. The values of the methylphenanthrene index are similar for the thermolysis products of asphaltenes and the parent oils. This similarity, in turn, allows the genetic identification of oils and evaluation of their catagenetic maturity by asphaltene thermolysis products in the case when biomarkers of the aliphatic fraction are lost during biodegradation. An analysis of the supermolecular structure of the asphaltenes of the oils under study has shown a general trend of its change by heating at 350°C, which consists in a sharp decrease in the particle size and loosening of the particle packing due to the appearance of pronounced porosity.

中文翻译：

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Timan–Pechora重油中沥青质的热解

摘要

研究了拉巴甘和美国油田的生物降解油和提曼–佩乔拉沉积盆地的萨留金斯科油田的非生物降解油中的沥青质热解产物的烃组成。沥青质的红外光谱相同，表明它们的结构基团组成相似。沥青质的热分解已在氩气流中依次在300和350°C下进行。已经表明，饱和和芳族组分从沥青质的孔中解吸主要发生在300℃。对于最初的生物降解油和未经过生化氧化的油，根据无环烃（HCs）和多环生物标志物计算出的许多地球化学参数与在350°C加热的沥青质的热解产物获得的参数相似。沥青质和母体油的热解产物的甲基菲指数值相似。反过来，在脂肪族馏分的生物标志物在生物降解过程中丢失的情况下，这种相似性又可以通过沥青质热解产物对油进行遗传鉴定并评估其催化成熟度。对所研究的油中沥青质的超分子结构进行分析后发现，在350°C加热时其变化的总体趋势是，由于油的出现，其粒径急剧减小，颗粒堆积松散。明显的孔隙率。