铀对Ⅰ型低熟烃源岩生烃演化的影响  

Effects of uranium on hydrocarbon generation of low-mature hydrocarbon source rocks containing kerogen type Ⅰ

作　　者：毛光周[1,2,3,4] 刘池洋[1,2] 刘宝泉 张东东[1,2] 邱欣卫[1,2] 王建强[1,2] 

机构地区：[1]西北大学大陆动力学国家重点实验室,陕西西安710069 [2]西北大学含油气盆地研究所,陕西西安710069 [3]山东省沉积成矿作用与沉积矿产重点实验室,山东青岛266590 [4]山东科技大学地质科学与工程学院,山东青岛266590 [5]中国石油华北油田分公司勘探开发研究院,河北任丘062552

出　　处：《中国石油大学学报（自然科学版）》2012年第2期172-181,共10页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：西北大学大陆动力学国家重点实验室科技部专项(BJ081334);国家自然科学基金项目(90814005);国家科技重大专项课题(2008ZX05023-001-002);国家重点基础研究发展计划(973)项目(2003CB214600);山东科技大学"春蕾计划"项目(2010AZZ009)

摘　　要：在Ⅰ型低熟烃源岩中加入砂岩型铀矿石的条件下进行生烃模拟实验,对比无铀-加铀样品生烃模拟实验产物的相关参数,探讨油气生成过程中无机铀所起的作用。结果表明:铀的存在促使长链烃类在400℃后裂解成低相对分子质量短链烃,烃类相对分子质量降低,向干气演化,CO2和H2大量生成,且铀的存在使得这一变化的温度点提前50℃;铀可以促进总油生成高峰的提前到来;350℃为铀使烯烃产量变化的转折温度点,烯烃开始向烷烃转变;铀的存在能提高模拟实验中生成的烯烃的异构化程度,并在整体上使生成的烯烃分子在晶格中排得更加紧密;加铀的烃源岩样品的生烃模拟实验产物在族组成、饱和烃气相色谱、生物标志化合物等方面表现出更加成熟的特征,铀可以使有机质的成熟度提高,有利于低熟烃源岩早期生成低熟油气,使铀的存在成为未熟-低熟油气形成的可能无机促进因素之一,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。Hydrocarbon-generating simulation experiment was proceeded using hydrocarbon source rock containing kerogen type Ⅰ with uranium（sandstone uranium ore） added.The effects of uranium on the hydrocarbon generation by relevant parameters of simulation experiment products were studied comparatively.The results show that uranium can facilitate the long-chain hydrocarbons cracking into low molecular weight hydrocarbons at the temperature above 400 ℃,as a result the molecular weight of hydrocarbons products is lowered.The degree of dry gas increases,while the CO2 and H2 are largely generated,and the uranium lowered the variation temperature for about 50 ℃.Uranium can lower the peak temperature of total liquid hydrocarbons generating.350 ℃ is the transition temperature of alkenes yield,above which alkenes changes into alkanes.Uranium can enhance the isomerization of alkene produced in the simulating experiment,and make the molecule lattice of alkene member arraying more closely.It s mature of products in the characteristic parameters of group composition,saturated hydrocarbon GC,biomarkers generated in the hydrocarbon-generating simulation experiment of hydrocarbons source rock with uranium.The uranium may enhance the maturity of organic matters.The existence of uranium in hydrocarbon source rocks is favorable to the generation of the immature hydrocarbons.It means that uranium in hydrocarbon source rocks is maybe one of the inorganic accelerating factors of the hydrocarbon generation.Such a small amount of hydrocarbon generated in advance can change the reservoir into a lipophilic reservoir,and it provides advantage conditions for migration and accumulation of late large-scale generated hydrocarbons.It makes the dense reservoir becoming large-scale industrial hydrocarbon reservoirs.

关 键 词：铀 烃源岩 低熟油气 成熟度 有机-无机相互作用 地质催化作用 生烃模拟 

分 类 号：P599[天文地球—地球化学]