【作者】 张敏；

【导师】 傅家谟； 盛国英； 潘长春；

【作者基本信息】 中国科学院研究生院（广州地球化学研究所） ， 地球化学， 2004， 博士

【摘要】 本论文在近几年前人对柴达木盆地北缘石油地质综合研究特别是烃源岩资源潜力评价的基础上,用含油气系统理论,重点采用油气源对比分析技术、烃源岩体系划分和评价技术、热史和生烃史研究技术、成藏期次的限定技术,研究烃源岩的发育层位与空间展布,油气源的对比,油气成藏过程及成藏模式,有利勘探目标。通过研究确定柴北缘有利生烃凹陷,油气的主控因素和富集规律,提出该区下步有利勘探区带和目标。 柴达木盆地北缘位于柴达木盆地的东北部,面积约30000km²,主要沉积地层有中生界侏罗统、白垩系。新生界第三系和第四系。根据烃源岩有机质含量、类型和成熟度确定柴北缘有两套烃源岩:下侏罗统烃源岩和中侏罗统烃源岩。两套烃源岩有机质丰度都比较高。下侏罗统有机质类型以混合型（Ⅱ₂）为主,中—高成熟度。中侏罗统有机质类型以Ⅲ型为主,局部(J_2d⁷)含有Ⅰ₂型油页岩,中—低成熟度。根据分子地球化学指标,下侏罗统和中侏罗统烃源岩都可划分为湖相和沼泽相两类。湖相烃源岩具有较低的Pr/Pn比值和C₁₉/C₂₁三环萜烷比值,较高的C₂₆三环萜烷/C₂₄四环萜烷比值和咖玛蜡烷/C₃₀藿烷比值和相对富集C₂₇规则甾烷贫C₂₉规则甾烷。沼泽相烃源岩上述比值的特征正好相反,与此相对应,根据上述分子指标,原油也可划分为湖相和沼泽相原油,以及同时具有湖相和沼泽相地球化学特征的混合原油,根据烃源岩的分布和油源对比,可确定冷湖和南八仙构造带的油气只能来源于下侏罗统烃源岩,而鱼卡、马北、红山和绿梁山地区的油气只能来源于中侏罗统烃源岩。 依据烃源岩特征和油源分析,将柴北缘划分为两大含油气系统,既:柴北缘昆特依凹陷J₁-J₁、E、N含油气系统和柴北缘赛什腾—鱼卡—尕丘凹陷J₂—J₃、E、N含油气系统,并对各含油气系统的分布范围、静态地质要素、基本地质作用进行分析。在对柴北缘典型油气藏进行解剖分析的基础上,总结了油气成藏特征和富集规律,提出了下步有利勘探区带。更多还原

【Abstract】 Based on the former integrated geological researches in the north fringe of Qiadam Basin, particularly on the evaluation on the potential capability of hydrocarbon source rock in the region, the developing strata of hydrocarbon source rock and their distribution, the contrast between oil source and gas source, the process and the model of the forming of oil and gas pool, and favorable exploration targets in the region have been studied and discussed thoroughly in this paper. A series of systematic theories including contrast analytical technology between oil source and gas source, classification and evaluation technology of hydrocarbon source rock, technology of thermo history and hydrocarbon creation history, and limitation technology of reservoir formation period were applied or adopted during the researches. Through the researches, a good sag of generating hydrocarbon in the region is determined; and the main factor of controlling the oil and gas and the law of accumulating oil and gas are identified as well. In addition, favorable exploration areas and targets in the region are pointed out in the paper.The north fringe of Qiadam Basin is located in the north-east part of the basin, the area is about 30000 km2, and the sedimentation strata include Jurassic (J) and Cretaceous (K) of Mesozoic (Mz), and Tertiary (R) and Quaternary (Q) of Cenozoic (Kz). According to the content, the type and the maturity of organic matter in hydrocarbon source rock, two sets of hydrocarbon source rock in the region are determined. One is lower Jurassic hydrocarbon source rock and the other is middle Jurassic hydrocarbon source rock. The abundance of organic matter in both hydrocarbon source rocks is relatively high. The type of organic matter in lower Jurassic hydrocarbon source rock mainly belongs to mixed type (type Ⅱ2), and the maturity is from middle to high. The type of organic matter in middle Jurassic hydrocarbon source rock mainly belongs to type Ⅲ, but Ⅱ2 petroliferous shale also exist partially (J2d7), and the maturity of organic mater is from middle to low. In terms of molecular geochemistry indexes, the hydrocarbon source rocks both in lower Jurassic and middle Jurassic can be classified as lake facies and swamp facies. For the hydrocarbon source rock in lake facies, both the ratio of Pr/Pn and the ratio of C19/C21 of tricyclic terpenes are lower, but the ratio of C26 of tricyclic terpene to C24 of quartcyclic terpenes and the ratio of gammaceran to C30 of hopane are higher; in addtion, C27 regular steranes is relatively abundant but the C29 regular steranes is relatively poor. Contrary to the hydrocarbon source rock in swamp facies, the ratios ofabove parameters are the very reverse. Correspondingly, crude oil in the region can be classified as lake facies and swamp facies according to above molecular geochemistry indexes; besides, mixed crude oil with the characteristics of lake facies and swamp facies simultaneously exists in the region. Based on the distribution of hydrocarbon source rock and the comparison of oil-source, the oils and gases in Lenghu and Nanbaxian structure belt come only from lower Jurassic hydrocarbon source rock; on the other hand, the oils and gases in the areas of Yuqia, Mabei, Hongshan and Luliangshan come from middle lower Jurassic hydrocarbon source rock only.In t erms o f the characteristics o f hydrocarbon so urce rock and the analysis o f oil-source in north fringe of Qiadam Basin, two main oil and gas systems can be classified, one of them is J1-J1/ E/ N system of Kunyite Sag and the other is J2-J3/E/N system of Saishenteng-Yuqia-Gaqiu Sag. The distribution area, static geological elements, and the basic geological functions of the two oil and gas systems have been analyzed and discussed in the paper. On the basis of elaborate analyses on the typical oil and gas pools in north fringe of Qiadam Basin, the characters of oil/gas forming and the law of oil/gas accumulation are summarized. Furthermore, favorable exploration areas are pointed out.更多还原