正构烷烃分布在确定烃源岩生源构成中的有效性

Effectiveness of n-alkanes distribution on determining parent material composition of hydrocarbon source rock

刘舵 谢春勤 陈治军 刘护创 韩长春 高怡文2

中国石油长庆油田分公司储气库管理处，陕西 榆林 718500 陕西延长石油（集团）有限责任公司研究院，陕西 西安 710075

Natural Gas Storage Management, Changqing Oilfield Company, PetroChina, Yulin 718500, China Reseach Institute of Yanchang Petroleum (group) CO., LTD., Xi′an 710075, China

在油气地球化学研究中，烃源岩（或原油）的正构烷烃被广泛应用于确定有机质来源，但文中研究发现，并不是所有烃源岩的正构烷烃都能很好地指示其生源构成。通过对银额盆地一口探井的烃源岩进行系统取样，基于测试资料，开展了正构烷烃分布特征在确定烃源岩生源构成应用中的有效性研究。结果表明，烃源岩成熟度对正构烷烃分布影响很大，未成熟和成熟—过成熟烃源岩的正构烷烃对生源构成均不具指示意义，只有在一定成熟度范围内，才有指示作用。以银额盆地中生界湖相烃源岩为例，只有满足镜质组反射率Ro为0.60%~0.80%时，正构烷烃才对生源具有很好的指示意义。文中确定的有效范围虽然只是研究个例，但因其具有广泛的代表性，对相关研究也有很好的借鉴作用。

N-alkanes in hydrocarbon source rocks and crude oils are widely used in the study of determining the source of organic matter, but in a related study, we found not all the n-alkanes are the good indicators to the source of organic matter. By systematically sampling of source rocks of a drilling well in Yingen-Ejinaqi Basin, the validity of the distribution characteristics of n-alkanes in determining the source composition of source rocks was studied based on test data. The results show that the maturity of source rocks has great influence on the distribution of n-alkanes, so the n-alkanes both for immature and mature-matured source rocks cannot indicate the source of organic matter, only within a certain range of maturity, n-alkanes have an indication on the parent material composition of hydrocarbon source rock. Taking the Mesozoic lacustrine source rocks in Yingen-Ejinaqi Basin as an example, n-alkanes have a good indication on the source of organic matter only when Ro is 0.60%-0.80%. Although the effective window determined in this study is only a case study, the study is representative and the results have good reference for related research.

10.6056/dkyqt201901010