渤海湾盆地济阳坳陷下古生界潜山勘探新认识与新发现

New understanding and discovery in exploration of Lower Paleozoic buried hills in Jiyang Depression,Bohai Bay Basin

下古生界潜山作为济阳坳陷重要的勘探目标,具有良好的油气形成与富集地质条件,相继发现了以桩西潜山、埕岛潜山等为代表的一系列大中型潜山油气田(藏)。目前济阳坳陷下古生界潜山进入高勘探程度阶段,通过潜山油气成藏条件深化认识,取得了一定的发现,实现了下古生界潜山勘探的突破。通过对断层性质、活动时间等与圈闭有效性的分析,认为北东走向、古近纪之后不活动、压扭性质的走滑断层具有一定的封堵性能,为负向构造型、斜坡型潜山勘探指明了方向。基于沟通油源断层走向输导能力的研究,提出超压环境下油气可以沿着断层进行横向输导,激活了没有直接油气来源的潜山块体的勘探局面。通过对烃源灶压力系统和断层纵向输导能力的研究,提出在超压环境、向上输导不利的条件下油气可以沿断层向下倒灌运移,使源下潜山勘探看到了希望。在新认识指导下,通过一系列的钻探,在埕北313、埕北古斜14、桩古65和车古27等潜山先后获得成功,新发现了一系列隐蔽型潜山油藏,打开了济阳坳陷下古生界潜山勘探的新局面。

The Lower Paleozoic buried hills,as important exploration targets in Jiyang Depression,have the good geological conditions of hydrocarbon enrichment and forming reservoir.A series of large and medium buried hill oilfields(reservoirs)such as Zhuangxi buried hill and Chengdao buried hill etc.have been discovered successively.With the high degree of hy⁃drocarbon exploration,some discoveries have been made with the improved understanding of reservoir forming conditions,and a breakthrough in the exploration of the Lower Paleozoic buried hill have been made as well.Through the analysis of fault property,active time and trap effectiveness,it is considered that the NE strike slip faults with characteristics of inactiv⁃ity after Paleogene and compression torsion property have certain seal performance,which points out the direction for explo⁃ration of negative structural and slope buried hills.Based on the study of the migration ability of the fault connecting to oil source,it is believed that hydrocarbon can transport laterally along the fault under overpressure environment,which acti⁃vates the exploration of buried hills without directly connections to source rocks.Based on the study of pressure system of hydrocarbon source and vertical transport ability of fault,it is proposed that hydrocarbon can migrate downward along the fault while being in block of migrating upward under the unfavorable environment of overpressure,which makes the explora⁃tion of buried hill under the source promising.Under the guidance of new understanding,Well Chengbei 313,Well Cheng⁃beigu xie 14,Well Zhuanggu 65 and Well Chegu 27 have been successively drilled,and a series of hidden buried hill reservoirs have been discovered,by which new prospects for the exploration of the Lower Paleozoic buried hill in Jiyang Depres⁃sion have been opened up.