【作者】 廖黔渝；

【导师】 王冠民；

【作者基本信息】 中国石油大学 ， 地质学， 2010， 硕士

【摘要】 以野外地质调查和烃源岩样品的化验资料为基础,并充分吸收前人研究成果,对分布在柴达木周缘18个石炭系剖面进行了详细沉积特征研究,细分出主要的沉积相类型,总结其演化模式,分析了研究区石炭系沉积规律,并对取自露头剖面的烃源岩作有机地球化学分析,对分析的数据进行了仔细研究,得到本区石炭系烃源岩有机地化特征,确定烃源岩的类型,品质特征;对沉积控制烃源岩发育的规律作了分析研究,并选出较有利的油气潜力区。对分布在柴达木盆地周缘的露头剖面,逐一进行野外踏勘、取样,绘制出剖面图,岩性柱状图,结合研究区的区域地质调查报告,以及其他一些有关本区石炭系的研究成果,对各个剖面沉积相分析,认为:(1)研究区石炭系主要为滨岸-浅海碳酸岩台地沉积环境,并细分了10种沉积相类型;由于滨浅海是较可能发育烃源岩的环境,所以详细分析了滨岸环境模式及其演化规律。研究区滨岸环境模式主要有两种:即潮坪-泻湖-局限台地模式和三角洲-局限台地模式。当滨岸地带陆源碎屑物质丰富时,潮坪、泻湖、障蔽砂坝相对比较发育;当滨岸地带陆源碎屑物质供应不足时,除潮坪、泻湖以外,障蔽砂坝被碳酸盐沉积所替代;而滨岸地带三角洲发育时,碳酸盐台地相的灰岩在前三角洲亚相的泥页岩之下是该模式最主要的特色。(2)通过对各个剖面地层划分和详细对比,归纳和总结了本区石炭系的沉积演化规律。在填平补齐的作用下,主要以陆相冲积沉积的阿木尼克组不整合于泥盆系或其他更古老的地层之上,随着海侵范围的不断扩大,逐渐转为滨岸—浅海碳酸盐台地沉积,到克鲁克组沉积期,潮坪-泻湖-障壁砂坝(碳酸盐台地)沉积体系更加发育,沉积厚度大,横向分布稳定。在对大量样品的有机地化测试数据的分析和研究为基础之上,评价本区石炭系烃源岩,其主要特征为:(1)石炭系可能的烃源岩类型为暗色泥岩,有机质丰度受沉积环境的控制,泻湖是烃源岩发育的主要环境;(2)有机质类型以Ⅱ2型为主,并见少量Ⅰ型、Ⅱ1型;(3)克鲁克组是最有利于烃源岩发育的层位,其沉积基准面从上升变为下降的转换期,可能是烃源岩发育的时期。(4)烃源岩有机质成熟度中等,已进入成熟阶段;成熟度最低的地区为柴东地区,少量烃源岩样品表现出低熟或未熟的特征。由东到西,由北到南,有机质的成熟的变高。(5)综合分析烃源岩的分布和有机质演化特征,锡铁山以西,石灰沟以东,扎布萨尕秀剖面以西地区,是较有利的油气潜力区域。更多还原

【Abstract】 Based on the field of geological survey and laboratory tests of samples and fully absorb the results of previous studies, the author have studied in detail the sedimentary characteristics of the 18 sections. in margin of the Qaidam Basin, identified the main types of sedimentary facies, summarize the evolution model of carboniferous deposition in the study area. The author studied the source rocks in the geochemical data carefully, and identified the type of source rocks, the quality characteristics. The Carboniferous source rocks are analyzed, and selected a more favorable area for oil and gas potential.The author investigated one by one for each section and took sample at first, draw a histogram profiles and lithology absorbed the report of regional geological investigation about the Qaidam Basin and the other results of previous studies. After that, some conclusions are drawn.(1) The sedimentary environment of Carboniferous is the shore - shallow carbonate platform facies.There are ten types of sedimentary facies, and it detailed analysis of coastal environment and its evolution model. Coastal environment of study area, are mainly two models that tidal flat - lagoon - limited platform model and Delta - restricted platform model. When the coastal areas rich in terrigenous material, the tidal flat, lagoon, sand bar relatively developed vasospasm. When the coastal zone terrigenous material in short supply, in addition to tidal flat, lagoon outside, vasospasm dam was replaced by carbonate deposition.(2)On each section through the detailed stratigraphic division and contrast, The authors concluded the deposition of the Carboniferous evolution. C1a is mainly terrestrial alluvial deposits, and unconformity on the Devonian or older strata. With the continuous expansion of the scope of transgression, sedimentary environment gradually turned into shore - shallow marine carbonate platform. During the deposition to the C2k, tidal flat - lagoon - Sand Barriers (carbonate platform) deposition system is more development, large sediment thickness, lateral distribution and stability.Evaluation of Carboniferous source rocks in this area is based on data of organic geochemistry analysis and research The main features of source rocks is that:(1)A possible source rocks of Carboniferous type is dark mudstone. Sedimentary environment controls the abundance of organic matter. Lagoon is the main environment of the hydrocarbon source rock development. (2) The type of organic matter is mainly typeⅡ2, and visible typeⅠ,Ⅱ1. (3) C2k is the best formation for the hydrocarbon source rock. Rise and fall of the exchange period of the Sedimentary base level of C2k may be a period of hydrocarbon source rocks. (4) Maturity of organic matter is the medium that has entered the mature stage. Maturity is the lowest in the eastern Qaidam Basin. A small amount of hydrocarbon source rocks show characteristics of low mature or immature. From east to west, from north to south, the maturity of organic matter changes in the high. After the comprehensive analysis of the distribution of source rocks, Qaidam Basin, Carboniferous oil and gas potential of the more favorable areas are the west of Mountain Xitie, the east of Shihuigou, the west of Zabushagaxiu.更多还原