渤海湾盆地埕岛油田前寒武系基底构造及储层特征

Precambrian Base Structure and Reservoir Characteristics of Chengdao Oilfield in Bohai Bay Basin

埕岛地区前寒武系强烈变形基底变质岩类,经多期构造运动及风化改造,成为良好的油气储层。基岩溶蚀孔洞及裂缝普遍发育,油藏具有众多独立潜山构造整体含油的局面。埕岛潜山构造演化经历了印支期潜山雏形的形成,燕山期拉张断陷复杂化,喜山期潜山定型3个阶段。形成了3组大的断裂,将基底潜山分割成带,形成了不同的断块、残丘、褶皱潜山储集体。基岩为前寒武系太古宇泰山群块状混合岩类变质岩。储层岩性变化大,储集空间类型多样,储层发育控制因素复杂。原生储集空间不发育,裂缝和溶蚀孔洞为主要的储集空间。储集空间发育程度及分布主要与岩石岩性、断裂和构造应力以及成岩后生作用有关。潜山构造演化及储层特征研究较好地指导了区域找油方向。

In Chengdao Region strong deformation occurred in Precambrian metamorphic basement,it experienced multi-period tectonic movement and weathering transformation and became a good hydrocarbon reservoir.In Chengdao Oilfield dissolution pores and fractures were extremely developed in the deep fault basement,and many independent buried hill reservoirs were oil-bearing on the whole.Chengdao buried hills experienced three stages of tectonic evolution.The Indo-Chinese movement made the rudiment of hill.Extensional faulted depression was complex at Yanshanian stage.Buried hills were finally divided into three stages in Himalayan movement,the basement was separated into belts by 3 sets of big faults and different fault blocks,residual hills,fold hill reservoirs were created.The matrix rocks were Precambrian Taishan Group metamorphic rocks of archaean.Reservoir lithology changed greatly with various reservoir space types.The reservoir development was controlled by complex factors.Primary porosity was not development,cracks and solution pores were the main reservoir spaces.Reservoir space development degree and distribution were mainly related with rock lithology,tectonic stress and late diagenesis.The study of Buried hill structure evolution and reservoir characteristics provide a direction for regional oil exploration.