东海盆地油气勘探焦点问题探讨

东海盆地自西向东可分为 3个带 ,即西部断陷带、中部隆起带和东部断坳带 ,其构造格局各具特色 ,并且均有自身的烃源岩。西部断陷带由多个以古新世为发育高峰期的半地堑组成 ,主要烃源岩为下古新统湖相泥岩 ,该带有利的勘探区是丽水、椒江凹陷 ,围绕下古新统主力烃源岩寻找油气是丽水、椒江凹陷油气勘探的焦点 ;中部隆起带是中生界残留盆地的叠置区 ,主要烃源岩为侏罗系湖相泥岩 ,福州凹陷是该带较有利的勘探区 ,烃源岩的规模、潜力以及圈闭保存条件是福州凹陷油气勘探的焦点 ;东部断坳带是厚度逾万米的新生代沉积断坳区 ,主要烃源岩为始新世煤系地层 ,该带有利的勘探区是西湖凹陷 ,烃源岩和盖层条件是西湖凹陷油气勘探的关键。目前 ,东海盆地比较现实和最具勘探前景的地区是西湖凹陷及丽水、椒江凹陷

A DISCUSSION ON SOME FOCAL PROBLEMS OF PETROLEUM EXPLORATION IN EAST CHINA SEA BASIN

From west to east, East China Sea basin can be divided into three zones, i.e. the western rifted zone, the central uplifted zone and the eastern depressed zone, and each zone is distinctive in structural framework and has itself source rocks. The western rifted zone is composed of many half grabens whose development peak stage is in Paleocene, and its main source rocks are Lower Paleocene lacustrine mudstones. The favorable exploration areas in this zone are Lishui and Jiaojiang sags, and to search hydrocarbon around the Lower Paleocene sources is a exploration focus in Lishui sag. The central uplifted zone is a superposted area on Mesozoic residual basins, in which the Jurassic lacustrine mudstones are the main source rocks. In this zone Fuzhou sag is a relatively favorable exploration area, whose focuses of hydrocarbon exploration are the size and potential of source rocks and the preservation of traps. With sediments thick over 10 km, the eastern depressed zone is a Cenozoic rifted and depressed region where the Eocene coal measures are the main source rocks and Xihu sag is the favorable exploration area. The keys of exploration are source rocks and seals in Xihu sag. At present, the most practical and promising exploration areas are Xihu, Lishui and Jiaojiang sags.