东营凹陷北部陡坡带稠油成藏机理与油气运聚特征  

Oil Migration and Accumulation Mechanisms for Heavy Oils in North Steep Slope of Dongying Depression, Eastern China

作　　者：李素梅[1] 庞雄奇[1] 邱桂强[2] 高永进[2] 孙锡年[2] 

机构地区：[1]石油大学石油与天然气成藏机理教育部重点实验室 [2]中国石化胜利石油有限公司,山东东营257015

出　　处：《地球科学（中国地质大学学报）》2004年第4期451-456,466,共7页Earth Science-Journal of China University of Geosciences

基　　金：国家重点基础发展规划项目 (G199943 3 10 ) ;国家"十五"攻关课题 ( 2 0 0 1BA60 5A0 9) .

摘　　要：东营凹陷北部陡坡带的王庄—宁海地区发现了大量稠油 ,但原油的成因及其成藏机理仍不甚了解 .在以往原油成因与油源调查基础上 ,利用非烃含氮化合物及包裹体均一化温度对该区进行油气运移方向与相对距离、成藏时间与期次的分析 .结果表明 ,东营凹陷北部带原油具有由南而北的运移分馏效应 ,反映北部陡坡带原油来自南部的利津洼陷 ;王庄—宁海地区原油总体具有由东而西的运移分馏效应 ,其东、西两侧各有一主要油气注气点 .王庄—宁海原油烃类与非烃组成与分布特征揭示该区油气具有混合聚集特征 .包裹体测试反映王庄—宁海地区油藏主要为晚期成藏 ,距今小于 5Ma ;而靠近生油中心地带包裹体具有早期成藏的记录 (± 36Ma) .A large amount of heavy oils are discovered in the north steep slope (NSS) of the Dongying depression, the Bohai Bay basin, Eastern China, but the mechanism of oil accumulation for this oil pools is still not well understood. Based on detail investigation of the composition for the oils and their source rocks, pyrrolic nitrocompounds and fluid inclusions have been analyzed to trace the process of oil migration and accumulation in the Wangzhuang-Ninghai region. The results show that apparent migration effects of nitrogen compounds within the oils from south to north, indicate that the oils in the north steep slope originate mainly from the Lijing sag in the Dongying depression. Obviously, migration effects from east to west observed in the Wangzhuang-Ninghai area indicate two main charging points respectively in the eastern and western areas. Composition of alkanes and non-alkanes and their distribution as well as pyrrolic nitrogen compounds show the origin of mixing of the oils. Alkanes with slight and/or no biodegradation and 25-norhopanes with strong biodegradation are observed in same oils, which indicates possibly multiple oil charging periods and/or redistribution of the oils due to tectonic movement. Two periods of oil formation and accumulation have been identified as evidenced from fluid inclusions. Oil pools in the Wangzhuang-Ninghai region were formed within 5(?) Ma before present. The oils generated in nearly 36(?) Ma ago as evidenced from inclusions in reservoir near the Lijing sag. A number of faults, several unconformities and a series of well developed fans with coarse sands and conglomerate in the NSS are taken as favored migration pathways for hydrocarbon in the study area.

关 键 词：稠油 含氮化合物 包裹体 油气运移 北部陡坡带 

分 类 号：P618.1[天文地球—矿床学]