摘要:
根据原油及油砂抽提物中含氮化合物分析、原油生物标志成熟度参数及储层流体包裹体烃类成分分析,研究了临南地区石油运移的方向、距离、成藏期次。结果表明临南油田仅有一期油气运聚成藏过程,属中新世末形成的成熟原油,4 甲基甾烷含量较高。曲堤油田存在两期油气运聚成藏过程,早期原油成熟度低,4 甲基甾烷含量低,运移距离较远,成藏后大部分散失 ;晚期充注的原油成熟度较高,4 甲基甾烷含量也较高,并保存至今。
Abstract:
Linnan Area iocated in western Jiyang Depression, Bohai Guif Basin. Formations reveaied by driiiing inciudes Cambrian, Ordovician, Carboniferous, Permian, Jurassic, Tertiary and Ouaternary. The third member(Es3 )of Shahe Jie Formation of Tertiary is the most important source rock of Linnan Sag and contributes to aii oiifieids around Linnan Sag. The Es3 has a sedimentary environment of deep to semi-deep iake facies, Kerogen type ! to Ⅱ1 in south and Ⅱ in north Linnan Sag and a high content of organic matter, so it possesses a great potentiai of hydrocarbon generation. The second migration direction and distance of oii are forecasted according to nitrogen-containing compounds and maturation indicators of biomarker in oii sand extracts. The oii in Linnan Sag migrated toward four main directions, i. e. Linpan, Shanghe, Outi and Linnan Oiifieid. The carbazoie content and C29 sterane S(/S + R)decrease and the 1- /4-methyi carbazoie increase with the distance increasing from the center of Linnan Sag to aii oiifieids around it. The anaiysis of hydrocarbon composition inside inciusions shows that oniy one process of migration and accumuiation of oii took piace in Linnan Oiifieid and that this kind of oii beiongs to mature oii formed during iate Miocene Epoch and have a high 4-mythyi sterane content. Two kinds of oii exist in Outi Oiifieid, the first, formed during iate Oiigocene Epoch, has a iow 4-mythyi sterane content and a iow maturation ievei, and migrated to far traps and then escaped. The second is mature oii with a high 4-mythyi sterane and have kept accumuiation state at present. In north area, the oii accumuiation process of Linpan Oiifieid has the same substance with Outi Oiifieid, and Shanghe Oiifieid is simiiar to Linnan Oiifieid.