不同沉积环境中原油氮同位素差异特征研究

Differences of nitrogen isotopes in crude oils from different depositional environments

刘娅昭 武明辉 师生宝 王杰 李伟

Liu Yazhao Wu Minghui Shi Shengbao Wang Jie Li Wei

中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126 2. 中国石油大学(北京) 油气资源与探测国家重点实验室, 北京 102249 3. 中国石化 石油勘探开发研究院, 北京 100083

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China 2. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China 3. SINOPEC Petroleum Exploration and Production Research Institute, Beijing 100083, China

氮作为原油及沉积有机质中的重要元素,由于不同沉积环境中母质来源不同和后期埋藏成岩过程不同,其含量和同位素比值明显不同.以尿素、咖啡因为标样,对不同沉积环境中原油氮的含量和氮同位素比值进行实验测定,发现由原油氮同位素值和氮的含量可以确定不同沉积环境,而且不同沉积环境中原油的碳同位素值与氮同位素值有很强的相关性,海相环境烃源岩形成的原油碳/氮同位素较陆相环境烃源岩形成的原油碳/氮同位素偏轻,其中氮同位素值的差异更加明显.对于相同沉积环境,原油受埋深高温裂解作用导致氮同位素分馏,使得原油中富集14N,从而高熟油氮同位素值偏轻.

As an important element of oil and organic matter, the contents and isotopes of nitrogen are different due to different sources from different environments and different late diagenetic processes after burial.The contents and isotopes of nitrogen in urea and caffeine show that these nitrogen parameters of samples are highly variable and indicate different depositional environments. The carbon and especially the nitrogen isotopes of crude oils formed in marine environments are lighter than those in continental environments, For samples from the same environment, high-temperature cracking causes nitrogen isotope fractionation. 14N is enriched in crude oils and nitrogen isotopes are lighter in high-maturity oils.

https://doi.org/10.11781/sysydz201501088