基于ESI FT-ICR MS分析技术的地质体中有机硫化物分布特征及其石油地质意义

The source rock of the marine oil and gases in the Tarim basin in western China has been disputed for more than two decades, and it seems that the conventional geochemical approaches such as GC and GC/MS techniques can not meet the requirement of revealing complex hydrocarbons generation and accumulation mechanisms in the basin. In this study, mainly marine oil and source rock samples with a wide range of maturity, sedimentary facies and litholgy with a few terrestrial oil and source rock from Kuche area for comparison in the Tarim Basin would be selected in order to investigate the distribution characteristics, controlling factors, formation mechanisms and the petroleum significances of the organic sulfur compounds (OSCs) in the crude oils and source rocks in the Tarim Basin by new techniques, including Fourier Transform Ion Cyclotron Resonance Mass Spectrometry with Electrospray Ionization (ESI FT-ICR MS), to investigate the organic sulfur compounds in whole oil or bitumen fraction such as SARA (saturated and aromatic hydrocarbons, resins and asphaltene) and Multicollector-Inductively Coupled Plasma Mass Spectrometer coupled with gas Chromatograph (GC-MC-ICP MS), to analyze the compound specific sulfur isotope. The emphasis will be put on the investigation of the impact of paleo-environment (i.e.,basinal facies and slope facies), lithology including carbonate and mud shale, kerogen type, thermal maturity on the organic sulfur compounds in the crude oils and source rocks. In combination with thermal model experiment, the dominant controlling factors and formation mechanisms of the organic sulfur compounds will be disclosed. Meanwhile, new indices such as facies and lithology, oil-source rock and maturity indicating parameters are expected to be explored and established. Particularly, the marine oil sources and the predominant source rocks in the Tarim Basin will be re-investigated by the new oil-source rock indicating parameters of organic sulfur compounds, in combination with oil-source rock correlations by traditional parameters under considering the impact of thermal maturity etc on the parameters. The relative contribution of the hydrocarbons from different source rocks would be calculated. The aim of this study is to disclose some puzzling questions about the origin and formation mechanisms of the Tarim marine oils. Two manuscripts about this work would be expected to be published in internal and international journals with a relatively high level.

塔里木盆地海相油气源一直存在争议，传统的分析测试技术难以满足该区复杂油气的成因与成藏机理研究需求。本课题拟采用国际最新的傅立叶变换离子回旋共振质谱（ESI FT-ICR MS）、GG-MC-ICPMS单体硫同位素等分析技术，以塔里木盆地海相烃源岩、原油为主要研究对象，揭示全馏分范围有机硫化合物的分布特征、主控因素、成因机制并阐明其地球化学意义。重点通过不同沉积相带/岩性、不同有机质类型与成熟度烃源岩、不同成因类型原油中有机硫化物的分布调查，结合热模拟实验，确认控制地下有机硫化合物的主要因素、揭示其成因机制；开发基于ESI FT-ICR MS分析技术的海相油源识别与高-过成熟度评价指标；在传统油源指标的成熟度等影响因素评价基础上，结合新研发指标，判识塔里木盆地海相油气源并评价其相对贡献。期待通过本项目的研究，解析塔里木盆地海相油气勘探中存在的科学难题。在国内外高水平杂志上发表SCI论文2篇。

塔里木盆地海相油气源一直存在争议。采用傅立叶变换离子回旋共振质谱（ESI FT-ICR MS）、单体烃碳/硫同位素等新技术，以塔里木海相盆地为主要研究对象、以渤海湾断陷盆地为辅助研究对象，揭示有机硫等化合物的组成与分布特征、主控因素及其地化意义，解析油气成因与来源。结果表明，海相原油/烃源岩含有较高丰度的有机硫化物，包括S1、O1S1、O1S2、S2、N1S1、N1O1S1、N1O2S1，以S1为主，其次为O1S1类，淡水相原油相对富含O1S1类；海相灰质类烃源岩及相关原油较泥页岩及相关原油具有较高丰度的有机硫化物及其种类，侧链碳数与缩合度也有所差异。观察到有机硫化合物受控于多种因素：生源/沉积环境控制有机硫化物的①种类和丰度、②化合物的组成与分布、③硫同位素。含膏盐岩、灰质岩类的海相和盐湖相烃源岩和相关原油富集有机硫化合物、硫化物发育较完整；泥质岩具有相反特征。观察到S1类、O1S1类相对丰度与Pr/Ph有较好的负、正相关性；低-正常成熟度样品中的有机硫的碳数分布记录了原始生源的构成。成熟度显著控制有机硫化合物的①组成与相对分布、②芳香度、③烷基侧链的碳数与长度。在低熟-正常成熟度范围，随成熟度增加：O1S1、O2S1类的相对丰度有降低趋势、S1类有增加趋势；S1类相对富集DBE=9系列、DBE=0～8系列丰度相对降低；硫化物分布范围变窄、侧链碳数有降低趋势。利用ESI FT-IDR MS和单体烃硫同位素技术，检测到塔里木海相、东濮盐湖相深层存在TSR作用，其为高芳香硫原油形成的重要原因。依据单体烃碳/硫同位素、生物标志物，提出塔中ZS1C（∈1x）井原油系寒武系成因、ZS1(∈2a)系奥陶系成因、塔中海相原油主要为混源油，预测出寒武-下奥陶与中上奥陶统成因原油的相对贡献比例约为57:43。依据ESI FT-ICR MS，提出塔里木盆地海相原油为灰质烃源岩与泥页岩的双重贡献。提出了多个基于ESI FT-ICR MS的生源/沉积环境与成熟度指标。本课题为开展NSO化合物的基础与应用研究提供了借鉴、为研究区油气勘探与开发提供了依据。