【作者】 陶树；

【导师】 汤达祯；

【作者基本信息】 中国地质大学（北京） ， 矿产普查与勘探， 2008， 硕士

【摘要】 南方海相下组合(震旦系—古生界)为重要油气勘探领域。本文研究重点片区系指川东南-黔中和鄂西-渝东及周边地区,含川东、鄂西豫东、黔北川南、黔东南、黔南、黔中、湘西北等七个区块。论文在烃源岩形成时的古沉积环境,明确有效烃源岩层位,分析各层位烃源岩有机质丰度及类型的基础上,通过有机岩石学与有机地球化学方法,运用BasinMod盆地模拟软件,结合七个区块埋藏史与热史资料,模拟烃源岩成熟演化史及生排烃史,划分烃源岩的生排烃期次,确定有利的生排烃区块。下组合烃源岩绝大部分达到过成熟的干气阶段,少量处在高成熟的湿气晚期阶段。通过对研究区七个区块烃源岩的埋藏史、热成熟史及生排烃史模拟,下组合烃源岩成熟演化,在时间序列上主要受寒武纪—志留纪、二叠纪—三叠纪、侏罗纪—白垩纪影响,在整个地质历史过程中主要发生3期的生排烃作用,分别对应于加里东中晚期、印支期和燕山早中期。南部(黔南、黔东南)进入“油窗”、“气窗”时间明显早于北部,震旦系—寒武系烃源岩于海西—印支早期即衰竭,志留系烃源岩也于印支期进入生烃衰竭;中、北部大片区域(川东、黔北-川南)震旦系—寒武系烃源岩于燕山早中期衰竭,志留系烃源岩此时处于生气高峰因抬升而停止产烃;鄂西-渝东、湘西北震旦系—寒武系烃源岩于海西—印支早期衰竭,志留系烃源岩于燕山中期刚进入“气窗”并因抬升而停止产烃;黔中地区受三次主要构造运动影响,地层抬升幅度较大,导致烃源岩生烃演化得以延缓,至今,震旦系—下寒武统烃源岩至燕山早中期仍具有生气潜力并因此时抬升而停止产烃。生排烃作用模拟实验通过烃源岩生烃过程、排烃效率、物质成分与相态转化,反映了高过成熟海相烃源岩油气发生与分配规律。研究区烃源岩已进入干气阶段,烃类产物全部为气体。Tmax递增迟缓,生烃效率增长很慢,生烃作用表现为已成烃类的裂解和干酪根生烃潜力的逐渐耗竭,气态烃主要来自重烃裂解而不是高度演化的干酪根本身。参照烃源岩对比样品生、排烃效率,南方下组合烃源岩有机质进入干气阶段后仍然具有5%左右的生烃潜量。更多还原

【Abstract】 Southern marine lower assemblage (Sinian-Palaeozoic) is an important oil and gas exploration filed.The researched area including northeastern Sichuan-cengtral Guizhou, western Hubei-eastern Chongqin and their surrounding areas can be divided into seven districts: eastern Sichuan, western Hubei, eastern Henan, southern Guizhou, northern Sichuan, northeastern Guizhou, northern Guizhou, cengtral Guizhou and northwestern Hunan.Based on the analysis of paleo-sendimentary environment of forming source rockes, effective source rocks strata and their organic matter abundance and types, through organic petrology and geochemistry, and the burial history and thermal evolution of these seven districts, maturity evolution history and generating&expelling hydrocarbon(GEH) history of these source rocks will be stimulated by BasinMod software, furthermore, GEH periods will be classified and then advantageous GEH area will be given.Most of the Lower Assemblage source rocks are at an over-mature dry gas stage, while some of them are at the high mature wet gas advanced stage.The results of the simulation of burial history, thermal matural history and GEH show that the Lower Assemblage source rocks evolution are effected by the deposition occurred in Cambrian-Silurian, Permian-Triassic and Jurassic-Cretaceous.So there are 3 periods of generating and expelling hydrocarbon:middle to late Caledonian epoch, Indo-Chinese epoch and early to middle Yanshanian epoch.The time of entering“oil window”and“gas window”in southern area(including southern and southeastern Guizhou) is earlier than in northern area, Sinian-Cambrian source rocks exhausted in the early Hercynian-Indo-Chinese epoch, and silurian source rocks also began to exhaust in the Indo-Chinese epoch;Sinian-Cambrian source rocks in most area of middle and north(including eastern Sichuang, northern Guizhou-southern Sichuang) exhausted in the early-middle Yanshanian epoch, meanwhile silurian source rocks were in the hydrocarbon generating peak but stopped due to tectonic uplifting;Sinian-Cambrian source rocks exhausted in the western Hubei-eastern Chongqing and west Hunan exhausted in the early Hercynian-Indo-Chinese epoch, and silurian source rocks stop generating hydrocarbon just after entering“gas window”because of tectonic uplifting;evolution of source rocks in the cengtral Guizhou were delayed because of sedimentary strata uplifting dramatically, and so far Sinian to lower-Cambrian source rocks still have potential in generating hydrocarbon in the middle Yanshanian but stopped due to tectonic uplifting.GEH stimulation experiments respect generation and distribution characteristics of high and over mature marine source rocks by generating hydrocarbon, expelling hydrocarbon efficiency of source rocks, and substance component and phase transform.The source rocks of researched area are in the period of dry gas evolution, and generate gas only.Tmax increase by degrees slowly and generating hydrocarbon efficiency rise very slowly.In the process of generating hydrocarbon, pyrolysis of the generated hydrocarbon occurred and kerogen generating potential exhausted gradually, and gaseity hydrocarbon came from pyrolysis of the heavy one mainly, instead of high evolution kerogen itself.The organic matter of source rocks in southern lower assemblage still have about 5% generating hydrocarbon potential after reaching dry gas evolution period, referring to GEH efficiency of the compared samples of source rocks.更多还原