东海陆架盆地烃源岩及其烃类特点

东海陆架盆地自古新世至渐新世发育了四套含煤烃源岩与海相陆源有机质烃源岩,其有机质类型属腐殖型。在结构镜质体的细胞腔中普遍充填着生源为高等植物针叶林的树脂体,其含量在煤岩中最高可占全岩体积的8%。镜下还见到油珠及与树脂体有产状关系的渗出沥青体。受有机质类型的制约,液态烃中均检测到大量二萜类树脂化合物及倍半萜类化合物。由于这部分源干高等植物的化合物在饱和烃中占有相当比例,加上成烃后的运移效应,使原油具有“六低一高”的特点,即低比重、低含硫、低含蜡、低主峰碳位、低芳烃、低胶质(无沥青质)和高饱和烃,并具低成熟煤成烃特征。

DISCUSSION ON SOURCE ROCK AND HYDROCARBON CHARACTERISTICS OF EAST CHINA SEA SHELF BASIN

There are four sets of source rocks developed in East Ch na Sea Shelf Basin,threes are coal-bearing sequences an the other one is of marine sequence with terrestrial organ matter.Organic matter in all the source rocks are of hum types with high content of vitrinite,low content of inertini(?) and a certain portion of liptinite (approximately14%).In th cells of structured vitrinite,resinite sourced from conifero(?) forest can be commonly seen by bulk-organic petrologic(?) examination.Its content in coal samples might reach a max mum of 8% by bulk volume of rock.Especially,hydrocarbo products,oil droplet and exudatinite that is thought to be re lated to resinite by its occurence can be found under fluores, cent microscope.Controlled by organic mattertype,a serie of diterpane resin compounds and sesquiterpenoids in liqui hydrocarbons have been detected.Owing to these biomarker from higher plants counting for considerable proportion c saturates,as well as migration effect after hydrocarbon gen eration,the oil is characterized to be of low density,low sul fur and low wax contents,lower carbon number peak,lo(?) aromatic contents and low resion or even no asphaltene wit high saturates and in addition,with characteristics of lo(?) matured hydrocarbons derived from coal.