上第三系是渤中坳陷及其周围油气勘探的主要领域

渤海海域经历了 30多年的油气勘探 ,直到 90年代 ,由于对渤海海域油气成藏的特殊性有了充分认识并用于指导实践 ,油气勘探才出现了重大转机。渤海海域油气成藏的特殊性表现在 :渤海海域是整个华北含油气盆地发育、发展的归宿 ;渤海海域新构造运动十分活跃 ,郯庐断裂在东营晚期—第四纪是强烈活动期 ,调整和控制了晚期成藏 ;渤中坳陷下第三系比周围陆区下第三系多一套东营组下段—沙河街组一段烃源岩 ;渤中坳陷上第三系明化镇组与馆陶组发育浅湖相沉积 ,是华北含油气盆地上第三系储盖组合最佳的地区 ;渤中坳陷与周围呈环状展布的凸起和低凸起带 ,构成了油气成藏的特殊地质结构。渤海海域油气成藏的特殊性 ,决定了勘探的主要目的层是上第三系馆陶组和明化镇组 ,找油气的主要方向是被生烃凹陷包围的凸起及其倾没带 ,包括分割凹陷和凸起的边界断层附近的各类反转构造。通过自营和合作勘探 ,相继发现了 QHD32 - 6、NB35 - 2、CFD11- 1、BZ2 5 - 1、PL19- 3等一批大中型油田 ,实现了渤海海域油气勘探的重大突破和转折 ,对海洋石油事业的持续发展和保持我国东部石油稳产将起重大作用

THE NEOGENE: A MAIN REALM OF HYDROCARBON EXPLORATION IN BOZHONG SAG AND ITS SURROUNDING AREAS

After more than 30 years of exploration, a major turn occurred in searching oil and gas in Bohai Sea during the 1990s as the peculiarity of hydrocarbon accumulation in the Sea was gradually revealed. This peculiarity is represented by: (1) The Bohai Sea is the end result of the whole North China Basin`s evolution; (2) Late hydrocarbon accumulation is adjusted and controlled by very active neotectonism, such as the major Tancheng lujiang Fault activated intensely from Dongying to Quaternary; (3) The Paleogene in Bozhong Sag contains a source rock of Lower Dongying Formation-Shahejie Formation`s Member 1 which is absent in the surrounding onshore areas; (4) A shallow lake facies is developed in Neogene Minghuazhen and Guantao Formation, making Bozhong Sag the best area of Neogene reservoir seal combination in North China Basin; (5) Bozhong Sag and its surrounding rises and low rises have constituted a play with peculiar geological features. In Bohai Sea, this peculiarity of hydrocarbon accumulation suggests that Neogene Guantao and Minghuazhen Formation are the main targets for exploration, and that the potential important prospects are rises and their plunged parts surrounded by hydrocarbon kitchens, as well as various reverse structures near the boundary faults by which sags and rises are segmented. By exploration of self operation and joint venture, several major oil fields, such as QHD32 6, NB35 2, CFD11 1, BZ25 1 and PL19 3, are successively found, resulting in a great breakthrough in Bohai Sea`s exploration, which will play an important role in developing offshore petroleum industry and stabilizing oil production in the eastern China.