生物降解稠油中沥青质热模拟实验

Thermal Simulation Experiment on Asphaltene in Biodegraded Heavy Oil

对准噶尔盆地西北缘正常原油和严重生物降解稠油中沥青质在不同温度下热模拟产物的生物标志化合物进行了对比分析,结果表明,300℃是较为理想的热模拟温度,在这种条件下,稠油沥青质热模拟产物中生物标志化合物的组成分布与正常原油较为一致,其生物标志化合物组成完整,未遭受生物降解,可用于严重降解油的油源分析,主要表现为:Pr/nC_(17)值和Ph/nC_(18)值相对偏高(分别为0.66~0.71和1.01~1.21),Pr/Ph值相对较低(1.15~1.21),伽马蜡烷指数相对较高(0.30~0.41),反映母质沉积环境为弱还原—还原的半咸水—咸水环境;三环萜烷以"C_(20)>C_(21)>C_(23)"模式分布,C_(23)三环萜烷/(C_(30)藿烷+C_(23)三环萜烷)值为0.46~0.49;Ts和C_(29)Ts相对含量极低,与典型风城组烃源岩的生物标志化合物分布特征基本一致。

The paper analyzes and compares the biomarkers in the products from asphaltene thermal simulation at different temperatures innormal crude oil and heavy oil suffered from serious biodegradation in the northwestern margin of Junggar basin.The results show that relatively ideal temperature for the thermal simulation is300℃,at which biomarker composition distribution of the products from the asphaltene thermal simulation of heavy oil is in accordance with that of normal crude oil.The biomarker in the simulation products of the heavyoil has complete compositions,indicating that it didn’t suffer from biodegradation and can be used to do oil source analysis for seriouslybiodegraded oil,which is featured with relatively high Pr/nC17and Ph/nC18(0.66~0.71and1.01~1.21,respectively),relatively low Pr/Ph(1.15~1.21)and relatively high gammacerane index(0.30~0.41),indicating a weak reducing-reducing and brackish water-saline water depositional environment of organic parent materials;a C20>C21>C23distribution pattern of tricyclic terpane and C23tricyclic terpane/(C30hopane+C23tricyclic terpane)of0.46~0.49;and extremely low content of Ts and C29Ts,showing that it is almost the same to the biomarkerin the typical source rocks of Fengcheng formation.