摘要
通过加强断陷盆地斜坡带层序地层研究,精细刻画沉积体系纵横向分布,创新构建油气成藏模式,发现落实地层岩性圈闭,有效地指导了冀中坳陷斜坡带地层岩性油藏勘探发现。以饶阳凹陷蠡县斜坡为例,应用单井层序划分—连井层序对比—地震层序识别—层序发育模式构建等"四步"法,结合冀中坳陷全区层序地层统层结果,指出蠡县斜坡古近系层序发育不完整,下部的二级层序(Es4—Ek)和SQ1—SQ6等6个三级层序发育差,而中、上部的2个二级层序和SQ7—SQ13等7个三级层序发育较齐全,形成了独特的层序演化和沉积充填样式。SQ9、SQ10是主要勘探目的层段,以发育辫状河三角洲和滨浅湖沉积体系为特征,辫状河三角洲平原分流河道、前缘水下分流水道和滨浅湖滩坝砂体构成了有利储集体。依据有利储集相带与古地貌配置关系,结合地层岩性圈闭发育特点和油源条件,构建了潜山周缘超覆、台坡砂体上倾尖灭、低幅鼻隆透镜体等3种地层岩性油藏模式,指导蠡县斜坡中北段油气勘探发现了亿吨级规模石油储量,取得了良好勘探成效。
Based on the research of sequence stratigraphy,sedimentary systems distribution,petroleum accumulation models and lithostratigraphic traps,great exploration breakthrough of the lithostratigraphic reservoir has been achieved in the slope zone of Jizhong Depression.Here,a case study has been made in the Lixian Slope of Raoyang Sag."Four-step"method including sequence division of single well,sequence correlation of connecting well,identification of seismic sequence and construction of sequence models was applied to study the characteristics of sequence stratigraphy.In Lixian Slope,the result suggested that its sequence stratigraphy framework of paleogene was incomplete,compared with Jizhong Depression.Its lower second-order sequence and six third-order sequences,from SQ1to SQ6,were not developed well.But the other two secondorder sequences,the upper and middle sequences as well as its seven third-order sequences,from SQ7to SQ13,were developed completely.Accordingly,there is an incomplete vertical sequence evolvement and filling series from fault-subsidence to depression.Two third-order sequence,SQ9and SQ10consisting good sourcereservoir-seal assemblages and possessing agood oil-bearing properties,become the main exploration target zone.Two different sedimentary systems including braided delta and shallow-shore lacustrine were classified in SQ9and SQ10.Moreover,subaerial and subaqueous distributary channel sandbodies of braided delta plain and front as well as beach-bar sandbodies of shallow-shore lacustrine,developed in TST and HST,formed the main favourable reservoir.According to the relationship between the favorable reservoir-facies belt and palaeogeomorphology,as well as the characteristics of lithostratigraphic traps and source conditions,different petroleum accumulation models of lithostratigraphic reservoirs,such as stratigraphic overlap reservoir around of buried hills,sandbodies updip and pinchout reservoir in the"platform-slop"area,and lenticular reservoir around of low-amplitude nosing structures were established respectively.After drilling,more than a hundred million tons of oil reserves were discovered in the middle and north part of Lixian Slope.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2012年第1期10-19,共10页
Earth Science Frontiers
基金
中石油股份公司重大攻关项目"成熟盆地油气成藏机制与精细勘探目标评价"(2010A-0612)和"冀中坳陷油气勘探新领域地质特征研究"(2008B-0303)
关键词
冀中坳陷
斜坡带
层序
地层岩性圈闭
勘探成效
J izhong Depression
slope zone
sequence stratigraphy
lithostratigraphic trap
exploration results