Abstract:

The absolute concentration of methyldiamantane is an indicator for determining cracking degree of oils. The diamondoids are often lost due to evaporation during oil samples processing. The whole-oil GC-MS analysis can be used to determine the absolute concentration of diamondoids accurately. The response factors of diamantane, D₃-1-methyldiamantane and D₆-1,3-dimethyladamantane are 1.91, 2.20 and 0.99, respectively, taking D₁₆-adamantane as an internal standard. The quantitative analysis of oils from Tahe Oilfield of Tarim Basin shows that the concentrations of 4-methyldiamantane+3-methyldiamantane in most oils range from 4×10^-6 to 35×10^-6, which indicates that the cracking degree of oils in this oilfield is low. There would have a prospect for petroleum exploration in the strata deeper than 6500m.

Key words: Tahe Oilfield, diamondoid compound, adamantane, diamantane, oil cracking, absolute concentration, quantitative analysis

摘要：

原油中甲基双金刚烷绝对含量是确定原油裂解程度的指标。运用全油色质方法,避免了样品处理中轻质组分的挥发损失,实现了原油中金刚烷化合物的准确绝对定量。使用D₁₆-单金刚烷为内标,确定双金刚烷、D₃-1甲基双金刚烷和D₆-1,3-二甲基单金刚烷的响应因子分别为1.91、2.20和0.99。塔里木盆地塔河油田原油中4-甲基双金刚烷+3-甲基双金刚烷绝对含量一般分布在(4~35)×10^-6,表明原油裂解程度较低,大于6 500m的深层可能仍具有石油勘探前景。

关键词: 塔河油田, 金刚烷化合物, 单金刚烷, 双金刚烷, 原油裂解, 绝对定量, 定量分析