摘要:运用三维地震、钻井资料,揭示了埕岛—桩海地区古生界与太古宇接触面滑脱构造基本特征及形成机理,剖析了其在油气勘探中的作用。主滑脱面为下古生界与太古宇之间的不整合面,表现为沿不整合面发育多条叠瓦状排列上陡下缓的低角度滑脱断层,倾末端收敛于不整合面,并未切穿下伏太古宇地层,致使滑脱断层切割形成的不同块体地层发生明显的翘倾旋转或缺失。平面上自西向东,滑脱强度、滑脱距离存在明显差异,西部滑脱作用强度最大,滑脱距离最远,导致下古生界地层严重缺失,中生界地层直接不整合覆盖于太古宇基底之上;中部滑脱作用活动强烈,滑脱距离较远,古生界潜山表现为一系列类似“飞来峰”的三角形残丘形态;东段滑脱作用活动较弱,古生界潜山被分割成一系列反向断块,各个断块地层保存相对较完整。综合分析表明,研究区潜山滑脱运动主要发生在郯庐断裂左旋走滑向右旋走滑的转换时期;滑脱作用改善了潜山储层物性,主滑脱面、滑脱断层与主油源断层共同构成了本区立体输导网络,为该区整体含油连片提供了有利条件。
关键词: 滑脱构造/
不整合面/
潜山/
储层/
输导网络/
埕岛—桩海地区
Abstract:By means of three dimensional seismic and drilling data, the basic characteristics and formation mechanism of the contact slip structure in Chengdao-Zhuanghai region are analyzed, and its role in oil and gas exploration is analyzed. Detachment surface is the unconformity surface between Lower Paleozoic and Archaeozoic, it shows that there are many overlaps and low angle slip faults with a low elevation along the unconformity surface. The tip terminal converges to the unconformity, without cutting through the stratum of Archaeozoic, the formation of different blocks formed by slip fault cutting is significantly warped or defeceted. There are significant differences in the slip strength and slip distance from west to east. The slip strength is the largest and the slip distance is the furthest in the west, resulting in the severe absence of the Lower Paleozoic stratum. Mesozoic strata are directly unconformable on the Archaeozoic basement. Sliding action is strong in central, and the slip distance is large, the Paleozoic buried hill presents a series of triangular hill forms similar to “klippe”. The decollation activity in the eastern section is relatively weak, and the Paleozoic buried is divided into a series of reverse fault blocks. The comprehensive analysis shows that the sliding movement of buried hill in the study area mainly occurs in the conversion period in which the Tancheng-Lujiang fault(Tan-Lu fault)from sinistral strikeslip to dextral strikeslip. The decollation improves the reservoir property of the buried hill. Detachment surface, detachment faults and oil source faults constitute the three-dimensional transport network in the region, which provides favorable conditions for the integrated oil and gas interconnects in this area.
Key words:Detachment structure/
Unconformity surface/
Buried hill/
Reservior transport network/
Chengdao-Zhuanghai region/
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