东海盆地西湖凹陷中央背斜带油气运移期次及成藏

利用包裹体测温和成岩矿物伊利石测年数据资料,对东海盆地西湖凹陷中央背斜带油气运移及成藏的基本模式进行了研究。中央背斜带储层流体包裹体明显分为盐水包裹体和有机包裹体,包裹体均一化温度分为3期,其对应的地质时间分别为中中新世、中新世晚期和上新世—第四纪。储层自生伊利石同位素地质年龄自北向南分别为23.5～26.5,18.31～21.86,12.58～13.63 Ma,表明北部油气成藏时间早于中部和南部。综合分析认为中央背斜带发生过早、中、晚3期油气运移和聚集活动,以晚期最为重要,其幕式特征明显。成藏期总体时间长,多期成烃,多次充注,同期不同源,是中央背斜带油气成藏的基本模式。

OIL AND GAS MIGRATION PERIODS AND ACCUMULATION PROCESS IN CENTRAL ANTICLINAL ZONE IN THE XIHU SAG, THE EAST CHINA SEA BASIN

By means of inclusion thermometry and authigenic illite dating data, the oil and gas migration and accumulation model in the central anticlinal zone in the Xihu Sag of the East China Sea Basin has been studied. Fluid inclusions in reservoirs in the central anticlinal zone can be divided into salt water inclusion and organic inclusion. Homogenization temperatures of inclusions can be devided into three periods and their accordingly geologic periods are Middle Miocene, Later Miocene and Pliocene to Quaternary respectively, Isotope ages of authigenic illite in reservoir are 23.5-26.5 Ma, 18.31-21.86 Ma and 12.58-13.63 Ma from north to south. This shows that the time of oil and gas accumulation in the northern part is earlier than ones in the middle and southern parts. The research result shows that there are three phases of oil and gas accumulation in the central anticlinal zone and the late-accumulation phase is the most impor- tant. Multiple phases of hydrocarbon generation, multiple recharging, multiple accumulation and multiple source rocks are fundamental oil and gas accumulation models in the zone.