【作者】 彭德华；

【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】 柴达木盆地是在前震旦纪结晶基底上形成的由不同阶段、不同类型盆地叠加起来的复合型盆地。盆地内主要发育了古生界、中生界和新生界三套地层。其中第三系主要发育在盆地西部（简称柴西地区）。 勘探实践证实柴达木盆地西部地区是以第三系咸水湖相为烃源岩的油气富集区,烃源岩以含盐度高（15‰～60‰）、含碳酸岩盐高（>20%）、有机碳含量低（一般Toc<0.5%）、烃转化率高（“A”/Toc一般为20%,最高可达60%以上;Hc/Toc一般为12%,最高可达40%以上）为其特征。且族组分和正烷烃碳同位素具有类似海相有机质的组成特征。 柴西第三系咸水湖相烃源岩有机质生源构成的特殊性造成了烃源岩两期生烃。第一期生烃为Ro<0.6%,主要以可溶有机质直接转化成未熟—低熟石油为主。第二期生烃为Ro>0.6%,主要以干酪根热降解生成成熟石油为主。 综合评价表明,E₃²生油层分布较广、厚度大,成熟度适中,是柴西尤其是南区及中区油气源的主力烃源层;因此,根据烃源层分布与生烃潜力状况,提出下步勘探应围绕狮子沟—油砂山构造带和油泉子—开特米里克构造带深层（E）以及阿尔金斜坡带等油源丰富的目标进行。并建议注重在浅层寻找未熟油的同时加强在深层找成熟油。更多还原

【Abstract】 The Qaidam basin, a complex basin superimposed on different stages and different types basin ,is formed from Pre-Sinian crystalline basement. Three sets of strata-Palaeozoic, Mesozoic and Cenozoic strata were developed in the Qaidam basin .Among them ,Tertiary strata is mainly developed in the west region of the basin (briefly called Qaidam basin west region).Exploration proved that the Qaidam basin west region is an oil /gas-bearing area with source rocks of Tertiary salty lacustrine facies , the source rocks are characterized by high salinity (15%~60%)、 high carbonate content (>20%), low organic carbon content(an average Toc <0.5 %, high conversion rate of hydrocarbon (an average "A"/ Toc is 20%, the highest "A"/ Toc is more than 60%; an average Hc/Toc is 12%, the highest Hc/Toc is more than 40% ). Moreover, the composition characteristics of group component and carbon isotopes of n-alkane are similar to that of organic matter in marine facies. In addition, the evolution of source rocks is characteristics of "two stages hydrocarbon-generating due to the particularity of organic matter bio-source composition in source rocks from the Tertiary salty lacustrine facies, the first stage of hydrocarbon-generating is at an early stage (Ro< 0.6%) which immature to low-mature oil was mainly formed by direct conversion of the soluble organic matters, and the second stage is at a late stage(Ro>0.7%) which mature oil was chiefly formed by thermal degration of kerogen.Comprehensive assessment shows that E32 source bed is the predominant source bed of the oil/gas resources for the west region of the Qaidam basin, especially for the south and north region because of its feature of wide distribution, broad thickness and moderate maturation; therefore, based on the distribution of source rocks and potential of hydrocarbon-generating, the author puts forward that Shizigou-Youshashan structure belt ,Youquanzi-Kaitemilike structure belt and Aerjing slope-belt with rich oil resource will become the exploration targets in the next step, meanwhile suggests that exploration for mature oil in deep layer should be emphasized while exploring the immature oil in shallow layer.更多还原