氮循环及氮同位素在古老烃源岩形成环境重建与油源对比中的应用  

Nitrogen cycle and nitrogen isotope application in paleoenvironment reconstruction of ancient hydrocarbon source rocks and oil-source correlations

作　　者：李婷婷[1] 朱光有[1] 赵坤 王鹏举 LI Ting-ting;ZHU Guang-you;ZHAO Kun;WANG Peng-ju(Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China;China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国地质大学(北京),北京100083

出　　处：《天然气地球科学》2020年第5期721-734,共14页Natural Gas Geoscience

基　　金：中国石油天然气股份有限公司科学研究与技术开发项目“古老碳酸盐岩油气成藏分布规模与关键技术”(编号:2019B-04),“深层烃源岩形成与分布”(编号:2018A-0102)联合资助.

摘　　要：烃源岩是油气勘探的物质基础,其质量和规模决定了油气资源潜力。沉积环境是原始生产力、营养物质供应、水体氧化还原条件及古气候等信息的综合反映,对优质烃源岩形成与分布起着重要的控制作用。然而,随着油气勘探不断向深层和超深层领域拓展,烃源岩经历的埋深和热演化程度随之增加,导致生物标志物及干酪根显微组分等反映成烃母质信息及沉积环境的常规地球化学指标失去指示意义。氮稳定同位素记录了氮循环的原始信息,是重建古海洋环境,探讨地史时期环境与生物演化关系,以及指示气候变化的可靠指标,在重建古老烃源岩形成环境、油源对比等方面也具有很好应用前景。在充分调研基础上,系统总结了海洋中的氮循环过程及氮同位素分馏效应,分析了沉积岩中氮同位素组成分布特征及其控制因素。Hydrocarbon source rocks are the material basis for oil and gas exploration,and their quality and quantity determine the oil and gas resource potential.Sedimentary environment reflects comprehensive informa⁃tion about primary productivity,nutrient supply,aqueous redox conditions,and paleoclimate,thus exerts a dominant control on the formation and distribution of high-quality source rocks.However,the burial depth and thermal maturation of these source rocks significantly increase as hydrocarbon exploration continuously expands into deep and ultra-deep strata,making many conventional geochemical proxies such as biomarkers and kerogen maceral analysis lose indicative significance for sedimentary environment.Stable nitrogen isotopes which record the original signals of marine nitrogen cycles are reliable indicators that can be used to reconstruct the paleoma⁃rine environment,explore links between environment and biological evolutions through the geological history,and indicate climate changes.In addition,this method also shows great application potential in oil and gas fields such as sedimentary environment reconstruction of ancient hydrocarbon source rocks and oil-source correlations.On basis of full investigation,this study systematically summarizes marine nitrogen cycle processes,nitrogen isotope fractionation mechanism,analyzes nitrogen isotope distribution and its controlling factors.

关 键 词：烃源岩 氮同位素 古气候 生物演化 氧化还原环境 油源对比 

分 类 号：TE122.113[石油与天然气工程—油气勘探]