【作者】 毛光周；

【导师】 刘池阳；

【作者基本信息】 西北大学 ， 矿产普查与勘探， 2009， 博士

【摘要】 在油、气、煤、铀多种能源矿产形成演化富集成藏(矿)过程中,有机-无机相互作用是普遍存在的,在有机质的强大吸附作用及其所提供的还原环境为铀矿的富集成矿起促进作用的同时,铀也改变了烃源岩的生烃演化进程。要就“铀对烃源岩生烃演化的影响”进行实验室模拟实验,所用烃源岩样品应该是低熟、并有源于其的工业油气藏的烃源岩。为尽量与实际地质事实相对应,所用的铀为砂岩型铀矿石,同时为简化实验中的影响因素,所用的铀还采用了碳酸铀酰溶液,以作对比研究。在烃源岩中加入铀(砂岩型铀矿石及碳酸铀酰溶液)的情况下进行生烃模拟实验。在对国内外烃源岩中铀含量的统计基础上,选择在烃源岩中所加的铀含量为50ppm(以碳酸铀酰溶液形式加入,无其它杂质,所以其含量取统计结果中的近似平均值)及100ppm、250ppm(以铀矿石的形式加入,考虑到铀矿石的复杂性及对铀作用的“稀释”作用,其含量取统计结果中的近似最大值)。实验采用高压釜反应器。实验结果表明,铀可以促进烃类生成过程中外来氢源中H的加入,使不饱和烃向饱和烃转化；促进长链烃的断裂,使高碳数的烃发生裂解,促进低分子量烃类的产生,从而使CH4的含量提高,生成的烃类的干气化程度增加；同时烃源岩生成更多的H2,进一步促进了模拟实验中烃源岩的烃气产率,为总气量的增加做出贡献。铀可以促进烃源岩液态烃的提前生成,并在低温阶段使液态烃大幅提高,促进烃源岩总烃的产量(物质的量或体积)。铀可以降低烃源岩饱和烃产量,增加芳烃产量,降低了族组分的饱／芳比,使烃源岩模拟实验产物中族组分表现出更加与低熟油相似的特征,意味着铀的存在利于低熟烃源岩早期生成低熟油气,铀的存在有利于低熟油气的形成。铀可以改变实验产物中饱和烃气相色谱特征参数,说明铀的存在可以使烃源岩的演化程度发生变化,促使低熟烃源岩的生烃门限降低,提前生成烃类；同时在高温阶段阻止有机质过度成熟,使其保持在较低的成熟度水平,利于所生成烃的保存。铀应该为低熟油、气生成的促进因素之一。这种提前生成的少量油气可以使所在储层变为亲油性,为后期大规模生成的油气运移成藏提供有利的条件,使得即使是致密的储层,也能形成大规模的工业油气藏。Ⅰ型与Ⅱ型及Ⅲ型的差别主要是因为：(1)铀矿石复杂,其中有的因素对铀的作用(在不同温度条件下)会有抵消作用；(2)Ⅰ型样品相对于Ⅱ型及Ⅲ型来说本来就具有相对较富的H,所以外源氢对其生烃的影响会有不同。更多还原

【Abstract】 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 betweenⅠ-type and (Ⅲ-type andⅡ-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,Ⅰ-type hydrocarbon source rock is relatively rich in H toⅢ-type andⅡ-type hydrocarbon source rock; therefore, the effect of external source hydrogen on the hydrocarbon-generation ofⅠ-type hydrocarbon source rock is different fromⅢ-type andⅡ-type hydrocarbon source rock.更多还原