柴达木盆地北缘油—气—煤—铀共存及其地质意义

发布时间：2018-04-09 14:01

本文选题：油气煤铀　切入点：多种能源　出处：《西北大学》2015年硕士论文

【摘要】：柴达木盆地是我国西部大型陆相沉积盆地之一,油气煤铀等有机、无机能源矿产丰富。对盆地北缘地区油、气、煤、铀的研究表明,它们不仅时空分布复杂有序,且形成过程彼此作用。平面分布方面,石油主要分布在柴北缘西段冷湖、赛什腾、鱼卡等地区,与煤相关的煤型气主要分布在冷湖、南八仙、马海等地区；可采煤炭资源沿柴北缘的冷湖—鱼卡—德令哈一线形成一条大规模的聚煤带；砂岩型铀矿分布于冷湖、鱼卡、北大滩、德令哈等地。地层层位方面,油气源岩为中下侏罗统煤系地层,储层主要是古近系—新近系；中下侏罗统的大煤沟组、小煤沟组是煤的主要赋存层位；砂岩型铀矿化则主要赋存于中侏罗统大煤沟组和石门沟组层间氧化带的前锋线上。上述特点构成柴北缘地区油气煤铀等多个不同类型的矿产组合,包括煤和煤型气的成生组合、砂岩型铀矿与煤、砂岩型铀矿与油气的共存组合,油气同源共生组合,煤型气与天然气水合物的共生组合等。目前对柴达木盆地油气煤铀单矿种的研究己日渐成熟,然而多种能源之间相互联系和彼此作用的研究却鲜少提及,是柴达木盆地能源矿产研究及勘探开发的弱点所在。柴北缘侏罗系是煤、砂岩型铀矿、煤型气等密切共存的层位,由岩石微量元素分析可知,侏罗系烃源岩中U、Mn、Mo、V、Cs等元素较为富集。在对该区烃源岩进行模拟生烃实验时加入不同比例的上述元素,所得结果的对比分析表明,这些无机元素的加入使烃类气体和非烃类的还原性气体产率有不同程度的增加,因此该区侏罗系砂岩型铀矿的存在应对烃源岩生烃(气)有着积极的促进作用。同时,柴北缘绿草山地区侏罗系发现有明显的由于天然气逸散所致的砂岩漂白现象,丰富的天然气还原剂又促进了砂岩型铀矿的后期叠加富集作用。依据上述多种能源的共存特点,在盆地北缘冷湖、鱼卡、德令哈地区划分了不同的油气煤铀协同勘探模式。总之,柴北缘地区油气煤铀同盆共存特征明显,其赋存层位相同或相近、形成过程彼此相关,其间存在着密切的内在联系和统一的沉积盆地动力学背景。这种内在规律的研究对本区能源矿产的协同勘探、多学科交叉的认识发展具有重要的理论和现实意义。
[Abstract]:The Qaidam Basin is one of the large continental sedimentary basins in the west of China, which is rich in oil, gas, coal, uranium and other organic and inorganic energy resources.The study of oil, gas, coal and uranium in the northern margin of the basin shows that they not only have a complex and orderly distribution in time and space, but also interact with each other in the formation process.In plane distribution, oil is mainly distributed in Lenghu, Saiteng, Yuka and other areas in the western part of the northern margin of Qaidam. Coal type gas related to coal is mainly distributed in Lenghu, Nanbaxian, Mahai and other areas.The recoverable coal resources form a large coal accumulation zone along the Lenghu-Yuka-Delinha line in the northern margin of Qaidam, and sandstone-type uranium deposits are distributed in Lenghu, Yuka, Beidatan, Delingha and other places.In terms of stratigraphic position, the source rock is the middle and lower Jurassic coal measure strata, the reservoir is mainly Paleogene-Neogene, the Daguigou formation of middle and lower Jurassic, the Xiaomeigou formation is the main coal formation, and the oil and gas source rock is mainly Paleogene-Neogene formation.The sandstone-type uranium mineralization mainly occurs in the front line of the interlayer oxidation zone of the Dawangou formation and the Shimenggou formation of the Middle Jurassic.The above characteristics constitute many different types of mineral assemblages, such as coal, coal, uranium and other mineral assemblages in the northern margin of Qaihai, including the formation and combination of coal and coal type gas, the coexisting combination of sandstone-type uranium deposits and coal, sandstone-type uranium deposits and oil and gas, and the hydrocarbon symbiotic assemblages.The symbiotic combination of coal type gas and natural gas hydrate.At present, the research on hydrocarbon coal and uranium monomineral in Qaidam Basin has become more and more mature. However, the research on the interrelation and interaction of various energy sources is seldom mentioned, which is the weakness of energy mineral research and exploration and development in Qaidam Basin.Jurassic in the northern margin of Qaidam is the horizon where coal, sandstone-type uranium deposit and coal-type gas coexist closely. The trace element analysis of Jurassic source rocks shows that the elements such as U _ (mn) Mo _ (Mo) V _ (C) _ (C) are enriched in the source rocks of Jurassic system.In the simulated hydrocarbon generation experiments of source rocks in this area, different proportions of the above elements are added. The comparative analysis of the obtained results shows that the addition of these inorganic elements can increase the yields of hydrocarbon gases and non-hydrocarbon reductive gases to varying degrees.Therefore, the existence of Jurassic sandstone-type uranium deposits in this area should play an active role in promoting hydrocarbon generation of source rocks.At the same time, in the Lucaoshan area of the northern margin of Qaihai, the phenomenon of sandstone bleaching caused by natural gas dissipation was found obviously, and the abundant natural gas reductant promoted the late superposition and enrichment of the sandstone-type uranium deposit.According to the coexistence characteristics of various energy sources mentioned above, different cooperative exploration models of oil and gas, coal and uranium have been divided in the Lenghu, Yuka and Delingha areas in the northern margin of the basin.In a word the coexisting characteristics of oil and gas coals and uranium in the northern margin of Qaidam are obvious its occurrence horizon is the same or similar and the formation process is related to each other. There are close internal relations and unified sedimentary basin dynamic background.The study of this inherent law is of great theoretical and practical significance to the cooperative exploration of energy and mineral resources in this area and the interdisciplinary understanding and development.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.1;P619.14

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