Abstract: There are abundant oil and gas in the lower Tertiary shallow layer of Dongying Formation in the northern Dongpu Sag.According to some geological and geochemical data of the studied region,including the homogenization temperature of fluid inclusion,the geochemical characteristics of crude oil and the evolution of fault,the hydrocarbon accumulation history in Dongying Formation was analyzed.The result shows that crude oil in Dongying Formation has the properties of high density,high viscosity and low maturity.The kerogen mainly came from the low aquatic hydrobiont in lake and formed in the environment of high salty and strong reduction.There occurred two charging periods of oil-gas in Dongying Formation of Wenliu area.The first stage of oil accumulation process occurred in the middle-late stage of Dongying Formation (from 21 Ma to 24 Ma before present),and the second stage happened after the Quaternary period (at 1.75 Ma before present).The first stage is the main generating period for oil reservoir which is down-genetic upper-stored type.Oil was from source rocks of salt-lake facies in the lower third member of Shahejie Formation.The reservoir with buried depth over 2 000 m is well preserved.

Key words: Dongpu Sag, geochemical characteristics, oil-gas accumulation period, crude oil, source rock, fluid inclusion

摘要： 东濮凹陷北部地区下第三系浅层东营组有丰富的油气藏,但对其认识还相对较薄弱。通过对研究区储层流体包裹体的分析,并结合东营组原油的地球化学特征及构造演化资料,对东营组油藏的形成历史进行了研究。结果表明:东营组原油密度大、黏度高、成熟度低,其母质来源以湖相低等水生生物为主,形成于咸化度较高的强还原环境。文留地区东营组曾发生过2期油气充注:第一期为东营组中后期(距今21~24 Ma);第二期发生在第四纪(距今1.75 Ma)之后。第一期为油藏主要形成期,原油来源于下部沙三段盐湖相烃源岩,为下生上储型油藏,埋深大于2 000 m的油藏保存较好。

关键词: 东濮凹陷, 地球化学特征, 油气成藏期, 原油, 烃源岩, 流体包裹体