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Effects Of Uranium On The Hydrocarbon Generation Of Hydrocarbon Source Rocks

Posted on:2010-04-19Degree:DoctorType:Dissertation
Country:ChinaCandidate:G Z MaoFull Text:PDF
GTID:1100360305957983Subject:Mineral prospecting and exploration
Abstract/Summary:PDF Full Text Request
Organic-inorganic interaction is ubiquitous in the process of formation, evolution, concentration and accumulation of various energy resources of oil, gas, coal and uranium. Uranium also alter the process of hydrocarbon generation and evolution of hydrocarbon source rocks while that organic matter accelerate concentration and mineralization of uranium by the strong adsorption and reduction environment from the organic matter.Hydrocarbon source rocks used in the hydrocarbon-generating simulation experiment is immature hydrocarbon source rocks, and there is commercial hydrocarbon reservoir formed by the hydrocarbon from the immature hydrocarbon source rocks. As far as possible correspond with the actual geological facts, the uranium used in the simulation experiment is sandstone-type uranium ore. To simplify the influence factors in the experiment, the uranium used in the experiment is also adopted the solution of UO2CO3 for comparative study.Hydrocarbon-generating simulation experiment is proceeded using hydrocarbon source rock with uranium added (sandstone-type uranium ore and UO2CO3 solution). The reactor used in the experiment is autoclave. The uranium added in the hydrocarbon source rocks is 50ppm (UO2CO3 solution); 100ppm and 250ppm (sandstone-type uranium ore) based on the statistics of the uranium contents in hydrocarbon source rocks from domestic to international.Experimental results show that uranium can facilitate H from external hydrogen source entering the hydrocarbon generation process, changing unsaturated hydrocarbons to saturated hydrocarbons, promoting the breaking of long-chain hydrocarbons, the high carbon hydrocarbon cracking, the low molecular weight hydrocarbons generating, so that the content of CH4 increased, the degree of dry gas increased, while the additional H2 generated from hydrocarbon source rocks, which promote the hydrocarbon gas yield and contribute to the increase of the total gas quantity in the simulation experiment.Uranium can promote the generation of liquid hydrocarbon prior, substantial increase the liquid hydrocarbons and total hydrocarbon production (amount of substance or volume) of hydrocarbon source rock at low temperature.Uranium can reduce the production of saturated hydrocarbons and increase the production of aromatic hydrocarbons of hydrocarbon source rocks in simulation experiment, so the ratio of saturated hydrocarbons to aromatic hydrocarbons is reduced. It is more similar to the immature hydrocarbons on the characteristics of group composition of simulation experiment products. The existence of uranium in hydrocarbon source rocks is favorable to the formation of the immature hydrocarbons.Uranium can alter the gas chromatography characteristic parameters of saturated hydrocarbons in simulation experiment. It indicates that the existence of uranium can alter the thermal evolution degree and maturity of hydrocarbon source rocks, reduce the hydrocarbon generation threshold values of immature hydrocarbon source rocks and advance the generation of the hydrocarbons, and delay the over mature of organic matter and made it retain a lower maturity that benefit the preservation of hydrocarbons at high temperature. It shows that uranium in hydrocarbon source rocks is one of the accelerating factors of the hydrocarbon generation.Such a small amount of hydrocarbon generated in advance can make the host reservoir into a lipophilic reservoir, and it provides advantage conditions for migration and accumulation of late large scale generated hydrocarbons. It makes even the dense reservoir becoming large-scale industrial hydrocarbon reservoirs.The difference on the hydrocarbon-generating characteristics betweenâ… -type and (â…¢-type andâ…¡-type) hydrocarbon source rock maybe mainly from two reasons. First, the composition of uranium ore is very complex; some factors in it may counteract the effects of uranium on the hydrocarbon-generation at different temperatures. Second,â… -type hydrocarbon source rock is relatively rich in H toâ…¢-type andâ…¡-type hydrocarbon source rock; therefore, the effect of external source hydrogen on the hydrocarbon-generation ofâ… -type hydrocarbon source rock is different fromâ…¢-type andâ…¡-type hydrocarbon source rock.
Keywords/Search Tags:uranium, hydrocarbon source rocks, immature hydrocarbons, maturity, hydrocarbon generation threshold, biomarkers, organic-inorganic interactions, geology catalysis, hydrocarbon generation simulation experiment
PDF Full Text Request
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