利用GC IRMS技术并结合 13X分子筛络合的方法 ,对克拉玛依油田不同生物降解程度原油中的萜类化合物进行单体碳同位素测定 .研究结果表明利用 13X分子筛能选择性地富集萜类化合物 ,使其满足GC IRMS的测定要求 ;另外 ,根据藿烷类单体碳同位素组成富13C(- 31.73‰～ 37.79‰ )的特征推测其可能主要来源于非嗜甲烷菌 ,结合其他地球化学方面的证据进一步表明克拉玛依油田的沉积环境为强还原的、快速堆积的封闭 半封闭湖相、咸化泻湖 . The carbon isotopes of terpenoids in terrestrial oils with different degrees of biodegradation in Karamay Oilfield were determined by GC-IRMS and 13X molecular sieve complexation.The results showed that 13X molecular sieves could selectively enrich terpenoids, Which meets the determination requirements of GC-IRMS. In addition, according to the characteristics of 13C (- 31.73 ‰ ~ 37.79 ‰) of the 13C (-31.73 ‰ ~ 37.79 ‰) of hopane monomer carbon isotopes, it may be mainly derived from non-methamidophos and combined with other geochemical evidence The results show that the sedimentary environment in Karamay Oilfield is a strongly reduced and rapidly accumulating closed and semi-closed lacustrine lagoon.