关键词: 冀中坳陷, 长洋淀地区, 古潜山内幕地层, 储盖组合, 成藏模式

Abstract: The buried-hill reservoir-forming mode of "new source rock-old reservoir" provided the exploration direction for a great number of buried-hill oil and gas fields such as Huabei Oilfield.With the increase of exploration degree,this kind of reservoir has been run out.The strata reflection texture,precisely reservoir-cap assemblages and distribution of buried-hill stratigraphy in Changyangdian area were studied by using available information of drilling,logging,laboratory test and high-quality 3D seismic data.The buried-hill stratigraphy includes the Lower Paleozoic Cambrian system,the New Proterozoic Qingbaikou system and the Middle Proterozoic Jixian system from top to bottom.Two reservoir-cap rock assemblages (the Cambrian Fujunshan Formation as reservoir and Mantou Formation as cap rock,and Wumishan Formation of the Middle Proterozoic Jixian system as reservoir and the New Proterozoic Qingbaikou system as cap rock) were developed.The reservoirs with predominated dolomites have good physical properties and developed fractures.Qingbaikou Formation of the New Proterozoic could be acted as the effective sealing formation for Wumishan Formation of the Middle Proterozoic.The hydrocarbon was derived from the Palaeogene,and the migration paths of hydrocarbon mainly included fault and unconformity surface.The buried-hill reservoir-forming mode of "old reservoir-old sealing formation" consequently generated.This mode was used to drill Chang3 Well where the high-yield oil production was obtained.

Key words: Jizhong Depression, Changyangdian area, buried-hill stratigraphy, reservoir-cap rock assemblage, reservoir-forming mode