Experiments Of Oil Or Gas-Uranium Relationship In The Hydrocarbon Generation Process Of Deep Source Rocks In The Ordos Basin And Its Geological Significance

The uranium coexistence characteristics of oil,gas,and coal in the Ordos Basin are obvious.In the northern part of the basin,the Zhiluo Formation produces the most important series of sandstone-type uranium deposits in China.The Chang 7 petroleum source rocks in the southwestern basin and the Upper Paleozoic natural gas and coal-bearing source rocks in the basin have The characteristics of uranium enrichment.Expulsion of uranium during hydrocarbon generation and hydrocarbon expulsion from source rocks,Under deep reduction and high temperature pressure conditions,The study of geochemical properties of uranium in a gas-oil-water mixed fluid,state of uranium and the form of migration and whether or not it can provide uranium ore sources for shallow sandstone uranium deposits,has important implications for scientific understanding of sandstone uranium mineralization and inorganic-organic interactions in the Ordos Basin.Papers using XRD analysis techniques,gas chromatography,ultraviolet spectroscopy,uranium geochemical analysis,high temperature and high pressure simulation experiments,etc.To simulate the environmental conditions such as temperature and pressure in deep source rocks,and to conduct experiments on hydrocarbon generation under conditions of series temperature and pressure changes.The uranium content in the source rocks of Chang 7 rich uranium source rock and the Benxi group enriched uranium coal series are analyzed.The existence condition of uranium,the main components of the generated oil and gas,and their effect on the reduction of uranium are studied.It provides new contents and scientific theoretical basis for the understanding of the geochemical properties of uranium under conditions of high temperature and high pressure and reducing fluids,and the sources of sandstone uranium ore deposits in the northern part of the basin.Hydrocarbon-enriched uranium-rich hydrocarbon source rock simulation experiments have shown that uranium can be emitted in a large amount while generating hydrocarbons in source rocks,Uranium is carried through oil adsorption,uranium hydrate colloidal forms,etc.,and as the temperature and pressure increase,the amount of uranium discharged also increases;There is a significant positive correlation between the amount of hydrocarbons generated and the rate of uranium carry-out,and the uranium carry-out rate can generally reach 55% to 75%.Experiments in oil or natural gas-uranium relationships under reducing conditions and at medium and high temperature and high pressure have shown that the uranium elements discharged in oil or gas-water mixed fluids can be either tetravalent or hexavalent;And UO2?UO3 ? tetravalent and hexavalent mixed oxides(U3O8 ? U3O7 and hydrates UO3·H2O ?U6O7·H2O,etc.)were adsorbed or migrated in the form of hydrated colloids.Based on this theoretical understanding of this work,it is believed that Chang 7 source rocks with uranium enrichment in the southern Ordos Basin and coal-bearing source rocks with uranium enrichment in Upper Paleozoic in the central North China can release or release uranium in large quantities while generating hydrocarbons and expulsing hydrocarbons.element,It is absorbed by underground oilfield water or gas-water fluids or in the form of hydrated colloids and migrates to shallow parts in a suitable geological structure.The formation and location of oil-gas-uranium energy minerals in the Ordos Basin are coupled with the dynamic evolution of the basin.After about 56 Ma,the Hetao rift formed in the north and cut off the source supply of the uranium mining area and its northern and northwestern source areas.However,there are a lot of young age data for the series of sandstone uranium deposits.The Perrhahaizi fault,which runs through the deep Paleozoic to shallow Jurassic and Cretaceous systems in this area,provides a channel for deep fluids to enter the shallow ore-bearing layers.Therefore,starting from the theoretical results of this work,combining the characteristics of basin-rich uranium source rocks and geological features and backgrounds of uranium deposits,we believe that the deep uranium-rich hydrocarbon source rocks in the Ordos Basin can provide uranium source for shallow sandstone-type uranium deposits.