断层与幔源二氧化碳气藏的形成和分布——以渤海湾盆地济阳坳陷为例

幔源CO_2气的形成和分布与不同级别断层早白垩世以来的活动密切相关。郯庐断裂带是研究区最主要的成气断层,拆离断层和变换断层这些地壳断层是次要的成气断层,二者于早白垩世143Ma、124Ma、新生代~43Ma、~24Ma和~8Ma的走滑或伸展活动,以及与之准同时的新生代碱性玄武岩浆活动,控制了幔源CO_2气的分散和聚集。它们与基底断裂、盖层断裂共同组成运移通道,其中拆离滑脱处的低速带和盖层断裂中的顺层断层是重要的水平运移通道。早白垩世古太平洋板块俯冲脱水脱气,产生的幔源CO_2气沿着郯庐断裂带向上分散聚集;新生代以来受控于太平洋板块俯冲方向和速度的改变以及印欧板块碰撞的远程效应,形成幔源CO_2气。与此同时郯庐断裂带切割深度亦逐渐加大,~43Ma碱性岩浆活动亦开始形成幔源CO_2气并主要位于断裂带,24Ma和8Ma(5Ma)为新近纪碱性岩浆活动脱气两个主要形成时期。郯庐断裂带的活动使地幔脱气形成的CO_2沿断层走向向上运移,并在作为重要横向运移通道的拆离断层拆离滑脱处,与因岩浆脱气形成的CO_2汇合,再通过陡倾斜、缓倾斜基底断层、盖层断层的接力传递在浅部聚集成藏。预测郯庐断裂带附近是无机成因油气重要的聚集分布区带。     

从地质—地球物理特征探讨甘肃西部扭压张构造变形

在地球物理场信息三维空间分析基础上,以走滑断裂尾端效应模式为指导,探讨了三危山、阿尔金左行走滑断裂产生尾端效应,在断裂东北端拉张凹陷,东南端挤压隆起,具备压、张、扭构造变形,同时认为不存在沿水系展布遥感解译的疏勒河断裂。     

华能宝兴电站引水隧洞富水涌泥断层破碎带施工中的 对策研究

华能宝兴电站引水隧洞工程开挖施工过程中,上游段遭遇T65断层带。因为这一断层破碎带的出现,该段曾发生4次突泥突水,严重影响了工程的进度。本文从工程地质角度研究该断层破碎带的工程特性,采用全断面帷幕注浆结合超前小导管注浆技术对富水涌泥断层破碎带进行加固止水,采用分步短进尺开挖,及时支护的方案进行隧道施工,保证了隧道施工的安全。该对策的有效实施为类似工程的施工起了一定的借鉴作用。     

The tectonic evolution of the Qiongdongnan Basin in the northern margin of the South China Sea

Qiongdongnan Basin is a Cenozoic rift basin located on the northern passive continental margin of the South China Sea. Due to a lack of geologic observations, its evolution was not clear in the past. However, recently acquired 2-D seismic reflection data provide an opportunity to investigate its tectonic evolution. It shows that the Qiongdongnan Basin comprises a main rift zone which is 50–100 km wide and more than 400 km long. The main rift zone is arcuate in map view and its orientation changes from ENE–WSW in the west to nearly E–W in the east. It can be divided into three major segments. The generally linear fault trace shown by many border faults in map view implies that the eastern and middle segments were controlled by faults reactivated from NE to ENE trending and nearly E–W trending pre-existing fabrics, respectively. The western segment was controlled by a left-lateral strike-slip fault. The fault patterns shown by the central and eastern segments indicate that the extension direction for the opening of the rift basin was dominantly NW–SE. A semi-quantitative analysis of the fault cut-offs identifies three stages of rifting evolution: (1) 40.4–33.9 Ma, sparsely distributed NE-trending faults formed mainly in the western and the central part of the study area; (2) 33.9–28.4 Ma, the main rift zone formed and the area influenced by faulting was extended into the eastern part of the study area and (3) 28.4–20.4 Ma, the subsidence area was further enlarged but mainly extended into the flanking area of the main rift zone. In addition, Estimates of extensional strain along NW–SE-trending seismic profiles, which cross the main rift zone, vary between 15 and 39 km, which are generally comparable to the sinistral displacement on the Red River Fault Zone offshore, implying that this fault zone, in terms of sinistral motion, terminated at a location near the southern end of the Yinggehai Basin. Finally, these observations let us to favour a hybrid model for the opening of the South China Sea and probably the Qiongdongnan Basin.     

呼和湖凹陷断裂特征及其对油气成藏的影响

断裂的形成演化过程对油气的运聚成藏具有重要的影响。本文系统分析了呼和湖凹陷断裂特征、断裂演化及其与油气成藏的关系。研究表明,呼和湖凹陷以T22和T04反射层为界,划分为3套构造层,分别为下部伸展断陷构造层、中部断坳构造层,上部坳陷构造层,其中上部构造层中断裂不发育。纵向上主要发育了两套断裂系统,下部断裂系统展布方向主要是北东东向、北东向和北北东向。上部断裂系统展布方向主要为北北东向和北北西向。发育4种类型的断裂,分别为早期伸展断裂,中期走滑断裂,早期伸展中期走滑断裂和早期伸展中期走滑晚期反转断裂。断裂的主要形成时期为南屯组末期、伊敏组末期和青元岗组末期。断裂的形成和演化影响烃源岩的分布和热演化程度,形成多种类型的圈闭,为油气垂向运移提供良好的运移通道。其中在主力生油洼槽及其周边的几个控陷断层附近有利于油气富集。     

西秦岭临潭-宕昌断裂第四纪最新活动特征

临潭-宕昌断裂是西秦岭造山带内一条重要的分支断裂,其最新活动特征是分析西秦岭构造变形的重要依据.临潭-宕昌断裂的新构造活动强烈,中强地震频繁,但目前对于断裂的新活动特征研究程度较低,未见有其全新世活动地质地貌证据的报道.文中基于遥感解译、宏观地貌分析研究断裂的长期活动表现和分段性;同时通过地质地貌考察、无人机摄影测量、...     

广西灵山地区的窗棂脊构造

在灵山地区北西向的六吉－蕉根坪断裂带上，存在着明显的窗棂脊构造地貌。叙述了该构造地貌的特征、形成时间及年变速率，并据此指出，该断裂具有较高的活动性，其地震危险值得注意。该构造地貌的发现为华南地区现今构造应力场和古地震的研究提供了新的信息。     

从地震信息看阿尔金断裂带构造和塔里木盆地花彩弧断裂体系

阿尔金断裂带由多条断裂组成,主要有阿尔金断裂、且末断裂、三危山断裂。其中阿尔金断裂为主断裂,它呈左旋走滑兼具逆冲性质,中生代—古近纪为左旋走滑,新近纪由东南向西北逆冲推覆。且末断裂和三危山断裂均具左旋走滑性质。且末断裂受统一的阿尔金断裂带左旋应力场控制,但又叠加了塔里木台盆区向南挤压的应力场,从而具有双重属性。塔里木盆地的断裂总体上组成古生界塔北花彩弧断裂束和塔南花彩弧断裂束,展布成全盆地的菱形断裂系统,且末断裂构成其东南边界。在该菱形断裂系统的北弧顶和菱形内的中央轴部为背冲式的构造断裂带,显示挤压特征;在花彩弧两翼转弯处展布正花状构造样式,显示走滑特征。阿尔金断裂带及其两侧,主要在柴达木、塔里木两大盆地发现了大油气田,两者都是由断层控制油气的垂向运移与分布。柴达木盆地具有双重断—坳的特点,但油气田只分布在中—新生界构造层内;塔里木盆地,南北翘板式的构造运动是其形成复式油气区的最重要的地质构造条件。     

鲁西隆起北部磁村断层走滑特征及其控藏意义

盆地周边地质调查是研究盆地构造演化的一种重要补充手段,露头区断层活动规律可以直观分析盆地内观察不到的断层性质。本文主要研究了磁村断层的野外地质特征及其对沉积的控制,并类比了沉积盆地内的断层对沉积的控制。研究发现磁村断裂带内地质现象丰富,发现有擦痕、阶步、碎裂灰岩、牵引褶皱、石香肠构造、菱形构造等,其中石香肠构造和菱形构造受控于岩性及断裂带内局部应力场变化,与其他证据共同指示磁村断层为一条右旋伸展-走滑断层。在此基础上分析了磁村断层走滑活动模式及对沉积扇体的控制,并针对断层走滑活动的沉积响应,在沉积盆地内找到了多处伸展-走滑型断层和走滑-伸展型断层控沉积的沉积迁移现象,且发现了走滑伸展作用产生的斜歪扇背斜现象。这种控制作用使沉积砂体沿断层走向展布,进而控制油气成藏和分布。综合分析认为,磁村断层形成于晚中生代以来鲁西地块的张扭性应力场,是鲁西隆起不同块体差异伸展所致,起调节不同块体应变的作用。     

Evaluation of geological factors in characterizing fault connectivity during hydrocarbon migration: Application to the Bohai Bay Basin

Faults play an intricate role in hydrocarbon migration and accumulation since they can serve either as a conduit or a seal. Quantitative evaluation of fault opening/sealing properties requires the selection of valid and optimal parameters among numerous geological factors to characterize the hydraulic behaviors of faults. The present study focuses on the Chengbei Step-Fault Area in the Qikou Depression, Bohai Bay Basin, NE China, because hydrocarbon migration and accumulation in this area occurred in a relatively short period so that accumulated hydrocarbons can be used as an indicator to deduce hydraulic connectivity of a fault zone between two sites. Various geological parameters pertinent to a fault, such as burial depth, dip angle, throw, strike, percentage of sandstone of faulted intervals, fluid pressure in faulted mudstone, stress normal to the fault plane, and shale gouge ratio, are analyzed to assess their effectiveness in characterizing fault connectivity. An index, the fault-connectivity probability (N_p), is proposed to evaluate the possibility that a fault has been once serving as a migration pathway. The statistical relationship between N_p and any a geological parameter may be used to indicate the effectiveness of this parameter in characterizing the connectivity of a fault during hydrocarbon migration. The correlation coefficient of a relationship is a good indicator of the effectiveness; and the results are generally in agreement with qualitative assessments. Parameters representing a single geological factor are generally ineffective, whereas those representing implicitly or explicitly two or more factors, such as shale gouge ratio, stress normal to the fault plane, and fault opening index, are more effective.