【作者】 孙永河；

【导师】 吕延防； 漆家福；

【作者基本信息】 大庆石油学院 ， 矿产普查与勘探， 2008， 博士

【摘要】 在区域地震剖面解释的基础上,研究了盆地结构特征及断裂构造特征,再结合盆地沉降史特征,从分析盆地变形序列、构建不同阶段的构造变形场特征入手,研究盆地的形成和演化过程及其动力学模式,从而揭示构造演化对油气运聚的控制。研究表明,渤中坳陷渤东-庙西地区为NW(NWW)断SE(SEE)翘的半地堑结构;秦南-石臼坨地区南段的半地堑结构为NW断SE翘,中段为不对称的地堑结构,北段为SE断NW翘的箕状半地堑;渤南地区为北断南翘的半地堑结构;渤中地区南段为拗断结构,中段和北段为SEE断NWW翘的半地堑盆地结构。渤中坳陷发育四种类型的断裂:即早期伸展断裂、中期走滑伸展断裂、晚期走滑断裂和长期活动的断裂。平面上划分渤东、秦南-石臼坨、渤南和渤中伸展断裂系统以及NNE向右旋走滑和NW-NWW向左旋走滑断裂系统等六个断裂系统。断裂强活动期主要有三期,其中,沙三段沉积时期主要形成NNE向、NE向、近EW向伸展断层和NW-NWW向伸展变换断层,东营组沉积时期叠加了NNE向右旋走滑伸展断层和NW-NWW向左旋走滑伸展断层,明一段—第四系沉积时期受郯庐断裂带走滑活动的影响使NNE向断裂再次发生右旋走滑活动。渤中坳陷古近纪裂陷阶段可进一步分为四个演化阶段,相当于孔店组-沙四段、沙三段、沙一二段和东营组沉积时期;新近纪-第四纪的后裂陷阶段可分为二个演化阶段,即馆陶组-明二段和明一段-第四系沉积时期。不同演化阶段的原型盆地结构特征不同,孔店组-沙四段沉积时期为“伸展拗陷盆地或伸展拗断盆地”;沙三段沉积时期为“伸展断陷盆地”;沙一、二段沉积时期为“伸展断拗盆地”;东营组沉积时期为“走滑伸展断拗盆地”和“伸展断拗盆地”的叠加复合。新近纪以来为受热地幔冷却下沉及郯庐断裂带右旋走滑活动等因素影响的“拗陷盆地”。盆地结构及构造演化特征表明,地幔底辟作用、区域构造应力场以及深大断裂是控制渤中坳陷演化的主导因素,地幔热底辟引起的地壳伸展作用具有双向伸展特征,控制伸展断裂系统的形成演化,区域构造应力场及深断裂带走滑作用控制NNE向郯庐断裂带和NWW向北京-蓬莱断裂带的共轭剪切走滑构造变形,形成走滑断裂系统。渤中坳陷的构造演化控制油气的运移和聚集。构造活动形成断裂为油气垂向穿层运移提供良好的通道条件,长期活动的断层是油气有效垂向运移的通道;构造强活动期的构造变形方式控制圈闭类型,沙三段沉积时期的伸展构造变形形成基底潜山和基底断块圈闭;东营组沉积时期走滑伸展构造变形形成扭动背斜、断背斜、断块、断鼻等圈闭;明一段-第四系沉积时期走滑构造变形形成扭动背斜和反转背斜圈闭。渤中坳陷重点勘探目的层为馆陶组和明二段,预测郯庐断裂带辽东湾与渤东段、渤东段与庙西段之间的转折凸起部位、渤中凹陷西斜坡南段的BZ8-4构造为相对最为有利的目标区。更多还原

【Abstract】 Based on interpretation of regional seismic sections, this paper researches basin structure and fault structure, and researches basin’s forming and evolutionary processes and dynamic mode which combined with subsidence history of basin and analysised deformation sequence of basin and constructed structural deformation field of different period, then reveals structural evolution controlled to migration and accumulation of hydrocarbon. Rsearch indicate that in Bodong and Miaoxi area, basin structures were half-graben of downward broken in NW (NWW) and upward warped in SE (SEE). In Qinnan and Shijiutuo area, basin structures are half-graben of downward broken in NW and upward warped in SE in south segment, are asymmetric graben in middle segment, and are half-graben of downward broken in SE and upward warped in NW in north segment. In Bonan area, basin structures are half-graben of downward broken in N and upward warped in S. In Bozhong area, basin structures were down-warped broken basin in south segment, and are half-graben of downward broken in SEE and upward warped in NWW in middle and north segment. In Bozhong depression, there were four types faults which were early extensional faults, middle strike-slip extensional faults, late strike-slip faults and long-term active faults. There were also six fault systems which were Bodong, Qinnan and Shijiutuo, Bonan and Bozhong extensional fault systems and NNE right-lateral strike-slip and NW-NWW left-lateral strike-slip fault systems. There were three fault active periods in Bozhong depression. First, there formed NNE, NE, closely EW extensional faults and NW-NWW extensional transfer faults during sha-3 member sedimentary period, then, superposed NNE right strike-slip extensional faults and NW-NWW left strike-slip extensional faults during Dongying group sedimentary period. Final, the NNE faults occurred right strike-slip movement which influenced by strike-slip displacement of Tanlu fault zone from Ming-1 member to Quaternary sedimentary period. In Bozhong depression, rifting stage of Paleogene was divided four evolutionary stages which were from Kongdian group to Sha-4 member, Sha-3 member, Sha-1 and Sha-2 member and Dongying group sedimentary period. While, later rifting stage was divided two evolutionary stages which were from Guantao group to Ming-2 member and from Ming-1 member to Quaternary sedimentary period. Structure of prototype basins was different on various evolutionary stages, that were extensional down-warped basin or extensional down-warped broken basin at form Kongdian group to Sha-4 member sedimentary period, were extensional faulted basin at Sha-3 member sedimentary period, were extensional broken down-warped basin at from Sha-1 to Sha-2 member sedimentary period, were strike-slip extensional broken down-warped basin and extensional broken down-warped basin at Dongying group sedimentary period, and were down-warped basin influenced by thermal mantle subsidence cooled and left strike-slip displacement of Tanlu fault zones since Neogene. Characteristics of basin structures and structural evolutions indicate that dominant factors of Bozhong depression’s formation and evolution were mantle diapirism, regional tectonic stress field and deep faults. Crustal extension induced by thermal mantle diapirism had bi extension and controlled formation and evolution of extensional fault systems. Regional tectonic stress field and deep faults controlled NNE Tanlu fault zones and NWW from Beij to Penglai fault zones conjugate shear strike-slip structural deformation and formatted strike-slip fault systems. In Bozhong depression, structural evolution controlled migration and accumulation of hydrocarbon. Structural activity formatted faults which provided vertical migration pathway of hydrocarbon. Long-term active faults were effective vertical migration pathway of hydrocarbon. Structural deformation of structural active period strongly controlled trap types. Extensional structural deformation of Sha-3 member sedimentary period formed basal buried-hill and basal fault-block traps. Strike-slip extensional structural deformation of Dongying group sedimentary period formed shear anticline, faulted anticline, fault-block and fault-nose trap and so on. Strike-slip structural deformation of from Ming-1 member to Quaternary sedimentary period formed shear anticline and reversal anticline traps. This paper thinks that Guantao group and Ming-2 member are mainly exploration target beds in Bozhong depression, and indicates that transition salient between Liaodongwan and Bodong segment and between Bongdong and Miaoxi segment of Tanlu fault zones and BZ8-4 structure locating the south of Bozhong sag’s western slope are most favorable target areas relatively.更多还原