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1.
多边断层(polygonal fault)是指主要发育干海相细粒沉积物中、具层控特征、平面上走向多方位且常相互交叉成多边形的小型伸展正断层,又称层内变形断层,一般认为属非构造成因.与构造正断层相比,多边断层明显具有层控性、多边性和放射等方性等特点.对多边断层几何形态特别是成因机制的深入研究对进一步认识泥岩压实、泥岩中流体活动和油气运移等都具有重要的指导作用.在调研大量国内外文献基础上,系统阐述了多边断层的几何特征和成因机制,并在此基础上尝试提出了一种新的综合机制--超压泥岩层幕式脱水收缩作用作为多边断层的成因. 相似文献
2.
根据新采集的三维地震资料,在西沙海域南部发现了多边形断层,其发育分布具有层控特征明显、在富泥地层中发育、多方位走向、纵向断距小、平面延伸长度小且形态为不规则多边形等特征。由于研究区东西两侧应力条件的差异,导致多边形断层发育特征的差异明显。通过对多边形断层发育控制因素的分析,认为地层岩性(特别是西沙海域上构造层的远源细粒沉积物)是其发育的主控因素之一,同时水道砂岩、成岩作用及构造作用等也是影响其发育分布的因素。多边形断层可以作为流体运移的通道,它与下部构造断层连接可将深部烃源岩中的油气运移到上部储层中聚集,或继续向上运移到浅部地层中形成天然气水合物。 相似文献
3.
松辽盆地三肇凹陷“T11”多边断层非构造成因机制探讨 总被引：4，自引：0，他引：4
地质学家过去一直关注松辽盆地“T2”高密度断层系,其成因机制存在很大的争议,但并没注意到“T11”也为高密度断层系。笔者系统研究了三肇凹陷肇州地区“T11”断层系几何学特征和形成的地质背景,首次提出“T11”断层为典型的多边形断层,仅从目前构造演化历史难以解释其成因,基于断层与较厚的青山口组具异常高孔隙流体压力的泥岩分布一致,认为多边断层为长期发育断层反转期再活动诱导青山口组泥岩层密度反转的成因机制,随着超压的积累断层周期性活动,是葡萄花油层油气运移的长期通道。 相似文献
4.
《中国地质》2020,(1)
多边形断层是一种非构造成因的小型层控伸展断层,多发育于细粒沉积物中,数量多且断距小,断层面在平面上呈不规则多边形排布,在剖面上呈倾向相近或相反的伸展断层。多边形断层的形成机制主要包括"密度反转"、"脱水收缩"和"剪切破裂",不同形成机制所主导的断层形态各有特点。"密度反转"的标志是波状地层接触面;"脱水收缩"的特征是犁状断层和生长层序,直接证据是海底沟纹和沉积物样品中的微裂缝;"剪切破裂"的特征是平直状断层和地堑-地垒式断层组合。多边形断层提高了细粒沉积层的渗透率,可作为烃类气、流体垂向运移的通道。脱水收缩形成的犁状断层流体输导性能可能弱于剪切破裂形成的平直状断层。天然气水合物作为浅表层烃类气、流体运移的产物,其赋存区域也可能会受到多边形断层的控制。分布较深的多边形断层可为天然气水合物提供气、流体运移通道,而分布较浅的多边形断层可为天然气水合物提供储集空间。 相似文献
5.
松辽盆地青一段发育大量密集分布的小型张性断层系,其成因一直以来颇受争议。本文选取松辽盆地三肇凹陷为研究区,通过新连片三维地震剖面精细解释及沿层相干切片分析等手段,详细描述了三肇凹陷青一段密集张性断裂系统的剖面和平面特征,提出:1青一段张性断裂系主体为非构造成因的多边形断层,其成因可能是由青山口组青一段泥岩超压幕式排烃破裂所导致,同时盆地构造反转活动对断层发育特征具有重要影响;2凹陷内多边形断层主要发育于嫩江组沉积末期,明水组沉积末期盆地强烈构造反转致使早期形成的多边形断层再活动,且对部分多边形断层的发育进行改造;3多边形断层起到沟通青一段烃源岩和分别位于其上部与下部的葡萄花、扶杨2个油气储层的作用,是凹陷内油气成藏的重要运移通道;4嫩江组沉积末期,超压使油气通过多边形断层从青一段短距离向下部扶杨储层"倒灌"运聚成藏;明水组沉积末期,超压导致油气沿重新开启的多边形断层向上部葡萄花储层或向下部扶杨储层运移聚集形成油气藏,同时垂向延伸较长的多边形断层对下部扶杨油藏可能具有一定的破坏作用。 相似文献
6.
为了对三肇凹陷T11反射层断层成因机制做出符合实际地质理论解释,本文鉴于前人各种非构造成因观点所存在的问题,从构造变形层间剪切力、断层线面密度关系、与国外哈默费斯特盆地典型的非构造成因多边断层解释特征对比3 方面, 对其成因机制做了定量分析。研究结果认为：1） T11 反射层断层为构造成因机制,是姚家组一段泥包砂地层结构受到上覆载荷作用构造变形时,在其泥岩层界面或层内优先发生层间滑动产生的内部作用力-层间剪切力所形成的切层断层和层内变形断层;2） 从断层线面密度关系计算结果来看,二者存在密切相关性,断层线密度越大面密度越大,这与构造成因断层空间分布规律相一致;3） 与哈默费斯特盆地的对比得出,T11反射层断层展布存在近南北向和东西向优势方位,其次是北北东向和北北西向,仅在几个鼻状构造带内发育走向随机的小断层,这些内部走向相对多方位的小断层实际上是由波状起伏的层间滑动断层及其伴生构造所形成的一种特殊构造现象。 相似文献
7.
塔里木盆地顺北地区奥陶系碳酸盐岩中广泛发育穹隆构造。为研究盆地深部穹隆构造的发育特征、成因机制及石油地质意义,基于顺北地区高精度三维地震资料,对穹隆构造开展几何学定量解析,确定其空间分布规律及内部结构样式;结合区域构造背景及盆内构造发育特征,明确其成因机制;在此基础上,结合生产动态数据探讨穹隆构造的控储—控藏作用。研究揭示：① 穹隆构造平面形态为椭圆形至近圆形,长轴主频方向为NE40°,展布趋势主频方向为NW20°,与邻近主干走滑断裂的距离呈正态分布;② 穹隆构造发育边部逆断裂和内部环形断裂,空间表现为锥体结构,其平面投影面积与隆起幅度正相关,隆起幅度自T74界面向下逐渐变小;③ 穹隆构造与走滑断裂处于同一区域应力背景下,但其与主干走滑断裂不具有成因关系,而是受控于岩浆热流体沿次级走滑断裂的垂向侵入,引起上覆地层隆起变形;④ 碳酸盐岩地层内,穹隆构造的边界逆断裂及顶部张裂缝均可作为良好的储集空间,其中“串珠体”(储集体地震响应)分布与边界逆断裂发育部位相稳合,推测为优质储集体发育部位。本研究可以深化盆地深部穹隆构造的成因认识;同时对顺北地区甚至塔里木盆地新油气目标类型的勘探评价提供指导意义。 相似文献
8.
断层对油气运移作用研究的新进展 总被引：11，自引：0，他引：11
断层与油气运移关系复杂 ,它对油气运移的作用一直受到广泛的重视。近年来 ,国内外学者在这一领域进行了大量研究 ,取得了一系列新成果和进展。在油气初次运移方面 ,Ｊ .Ａ .Ｃａｒｔｗｒｉｇｈｔ( 1994 )用水力压裂成功地解释了北海盆地早新生代超压泥岩层序中高密度分布的层间断层的成因和流体排出的机制。这些断层是小型伸展构造 ,成簇发育、几何形态复杂 ,其成因与盆地范围的超压封闭箱的幕式崩溃及大量流体流出有关。水力压裂或流体压裂 (ｈｙｄｒｏｆｒａｃｔｕｒｉｎｇ)是由于孔隙中流体压力的增大而导致低渗岩石的破裂 ,破裂面通常… 相似文献
9.
盆地深部穹隆构造发育特征、成因机制及石油地质意义——以塔里木盆地顺北地区为例 总被引：1，自引：0，他引：1
塔里木盆地顺北地区奥陶系碳酸盐岩中广泛发育穹隆构造.为研究盆地深部穹隆构造的发育特征、成因机制及石油地质意义,基于顺北地区高精度三维地震资料,对穹隆构造开展几何学定量解析,确定其空间分布规律及内部结构样式;结合区域构造背景及盆内构造发育特征,明确其成因机制;在此基础上,结合生产动态数据探讨穹隆构造的控储—控藏作用.研究... 相似文献
10.
准噶尔盆地中部地区侏罗系压扭断裂体系样式及其控藏作用研究 总被引：1，自引：0，他引：1
中国西部盆地的腹部压扭断裂体系比较发育,但对其断裂组合样式及其成因机制认识程度较低,这已成为重点勘探领域由盆缘向盆内战略展开的瓶颈问题。基于对准噶尔盆地中部地区侏罗系多个构造单元压扭断层几何学特征及其应力-应变状态分析,明确了燕山Ⅱ幕压扭断层是深部基底强烈压扭形变发育至中浅层的直接响应,具有以压为辅、以扭为主的成因机制。与准中地区"棋盘格"底形构造密切相关,侏罗系压扭断层具有"三带一区"四类典型组合样式和展布规律。两组不同走向断层大致呈共轭剪切关系,在平面上构成完整或不完整菱形几何学形态。据库伦破裂准则和地震剖面特征可判识出,锐角区具有明显挤压性质,而钝角区具有伸展性质。较高勘探程度区块钻探成果及试油效果证实,锐角挤压区断面封闭性较好,是油气主要富集单元;钝角伸展区断面普遍开启,是油气纵向输导区。研究成果反映了我国西部陆内坳陷区压扭断裂体系组合样式、成因机制及其控藏作用研究的新进展,对准中地区侏罗系下一步油气勘探具有很大启示意义。 相似文献
11.
深水盆地中多边形断层的几何特征与形成机制探讨 总被引：4，自引：0，他引：4
多边形断层是指一种在平面上呈多边形具有微小断距的张性断层系。自1994年被提出以来, 已有十余年的研究历史, 并在世界50多个被动大陆边缘盆地中被识别出来。研究多边形断层需要高精度的3D地震资料。我们根据琼东南盆地3D地震资料并利用相干切片技术, 首次在琼东南盆地南部发现了多边形断层, 并对其进行了初步研究。多边形断层的成因机制是前期多边形断层研究的重点, 许多学者认为深水沉积物早期压实脱水体积收缩形成的; 也有学者认为重力扩展控制断裂的发育。岩石物性、成岩作用及构造应力是影响多边形断层发育的重要因素。多边形断层对深水盆地的油气储集体的性质和分布; 以及油气、天然气水合物的运移和聚集有着重要的意义。 相似文献
12.
中国西部盆地台盆区高角度断层的成因及控油气作用分析 总被引：2，自引：0，他引：2
给出了中国西部盆地台盆区普遍发育高角度(倾角 > 45°) 断层的证据, 从断裂形成的力学机制上分析了高角度断层的成因, 认为中国西部盆地台盆区高角度断层的形成主要受压扭性应力场控制, 同时与脆性地层的变形特点有关.断层面静封闭压力由岩石泊桑比、上覆地层容重、断层埋藏深度和倾角、最大和最小主应力以及断层走向与最大主应力方向的夹角等计算, 作为断层开启性评价的一个指标, 断层面静封闭压力的计算表明, 断层的开启性随断层倾角的增加而增加, 同时, 沿断层面运移的油气所受浮力在平行断层面方向上的分力也随着断层倾角的增加而增加, 这就决定了高角度断层更有利于油气的垂向运移.结合西部盆地的具体分析, 认为中国西部盆地区域性高角度断层是沟通深部成藏动力学系统与中上部成藏动力学系统的重要通道, 是中上部系统成藏的关键, 直接决定着中上部系统中油气的分布, 在每一系统内部发育的高角度断层具有使油气在断层断开的最新层位中优先充注成藏的基本规律.这些认识对指导油气勘探具有重要意义, 而且, 这些认识同样可推广到其他存在高角度断层的盆地中. 相似文献
13.
Eugenio E. Veloso Daniele Tardani Daniel Elizalde Benigno E. Godoy Pablo A. Sánchez-Alfaro Felipe Aron 《International Geology Review》2020,62(10):1294-1318
ABSTRACT Geothermal exploration in the Central Andean Volcanic Zone (CAVZ) focuses on heat capacities of known geothermal systems, yet the role of faults, veins, fractures and folds on the evolution and migration of fluids is far from complete. Here, we present a compilation of He and Sr isotope data and newly generated structural maps to examine if particular tectonic configurations are associated with fluids migrating from different crustal levels. Accordingly, we defined three tectono-geothermal environments (T1–T3) depicting specific structural arrangements and spatial relation with geothermal and volcanic manifestations. T1 is dominated by left-lateral strike-slip NW-striking faults, and geothermal and volcanic manifestations occur along the traces of these structures. T2 is dominated by N-striking thrust faults and parallel fault-propagated folds, cut and displaced by NW-striking faults. Here, geothermal manifestations occur at fault intersections and at fold hinges. T3 is defined by left-lateral/normal NW-striking faults, with geothermal and volcanic manifestations lying along fault traces. Each tectono-geothermal environment yields distinctive isotope ratios and geothermal reservoir temperatures. T1 shows high helium and low strontium ratios, and temperatures between 220° and 310°C. T3 shows low helium and high strontium ratios and temperatures between 260° and 320°C. T2 isotope ratios fall between T1 and T3, with lowest (130°-250°C) reservoir temperatures. We argue that these particular isotope signatures are due to a structural control on reservoir location and orientation. The orientation of the fracture mesh genetically associated with each tectono-geothermal environment is a first-order control on the migration pathway of fluids. Our model shows that T1 allows fluxing of deeper fluids, T2 promotes storage and favors longer residence times and T3 enhances subvertical fluid migration. Results here help to explain the evolution of geothermal systems in a wider context, including fault systems and Sr and He isotope variations, thus providing a framework for geothermal exploration in the CAVZ. 相似文献
14.
Abstract The definition of the active fault geometry and kinematics in young evolving orogens may be difficult owing to changes in the structural architecture which may occur with a frequence of few hundred thousand years. Cases from the central Apennines well illustrate this problem. The Avezzano-Bussi and Vallelonga-Salto Valley fault systems (65 and 85 km long, respectively) show clear evidence of Pliocene-early Pleistocene activity and have been responsible for the formation of intermontane basins. Available geological data, however, indicate that only minor segments (the Tre Monti and Trasacco faults, both 7 km long) of the mentioned faults have to be considered active during the late Pleistocene-Holocene, as faults accommodating minor deformations inside an intermontane basin. The L'Aquila fault system underwent significant geometrical and kinematic modifications during the Quaternary, with the reactivation of minor portions of parallel normal faults to draw a new system of en-echelon normal-oblique left-lateral faults. The Laga Mts. fault experienced an along-fault activity migration. The portion of the fault which was active earlier during the Quaternary shows a significant decrease or end of the activity while a portion previously not active displays impressive evidence of late Pleistocene-Holocene displacements. Structural changes in the intermontane basins bounded by the Colfiorito fault system also indicate that the intensity of the tectonic activity decreased during the Quaternary. Not defining the structural evolution in the above mentioned cases would imply wrong conclusions for both the fault geometry and kinematics which may be delivered for seismotectonics and seismic hazard assessment. This typically leads to overestimate the fault length and the expected magnitude or to the increase in the number of seismogenic sources affecting an area. Finally, the definition of the structural evolution permits to select between different geometrical options in terms of active faulting framework (e.g. a system of parallel normal faults vs. a system of en-echelon normal oblique faults as in the case of the L'Aquila fault system) related to different geometries at depth (detachment normal fault vs. high-angle oblique fault). © 2001 Éditions scientifiques et médicales Elsevier SAS 相似文献
15.
Deformation studies require that geological bodies are kinematically moved along faults. Fault-parallel flow is one of a small number of kinematic restoration algorithms developed for this purpose. This scale-independent method describes how material nodes are displaced parallel to the fault plane, in the direction of fault movement. The one-dimensional strain of linear objects and two-dimensional strain of bodies within the hanging-wall during the restoration is shown for all cutoff angles and all angles of fault bends. A line moving over a fault bend is either shortened or extended depending on its initial orientation. However, the elongation of the line is significantly different under shortening and extension, with respect to the fault bend angle. The geometries of compressional fault systems, in which faults change angle by about 20 to 40°, generate low values of elongation. Modeling of extensional faults, which typically have steeper dips (60 to 80°) and therefore have tighter fault bends, causes high, unnatural values of elongation. The calculated strain ellipse ratios are directly proportional to the fault bend angle, corroborating the one-dimensional results. The fault-parallel flow method should be used primarily to kinematically restore and forward-model compressional faults, and other faults where the fault bend angles do not exceed 40°. 相似文献
16.
WU Guanghui YUAN Yajuan HUANG Shaoying Thomas Matthew Vandyk XIAO Yang CAI Quan LUO Bingxu 《《地质学报》英文版》2018,92(1):74-88
Recent studies, focused on dihedral angles and intersection processes, have increased understandings of conjugate fault mechanisms. We present new 3-D seismic data and microstructural core analysis in a case study of a large conjugate strike-slip fault system from the intracratonic Tarim Basin, NW China. Within our study area, "X" type NE and NW trending faults occur within CambrianOrdovician carbonates. The dihedral angles of these conjugate faults have narrow ranges, 19° to 62° in the Cambrian and 26° to 51° in the Ordovician, and their modes are 42° and 44° respectively. These data are significantly different from the ～60° predicted by the Coulomb fracture criterion. It is concluded that:(1) The dihedral angles of the conjugate faults were not controlled by confining pressure, which was low and associated with shallow burial;(2) As dihedral angles were not controlled by pressure they can be used to determine the shortening direction during faulting;(3) Sequential slip may have played an important role in forming conjugate fault intersections;(4) The conjugate fault system of the Tarim basin initiated as rhombic joints; these subsequently developed into sequentially active "X" type conjugate faults; followed by preferential development of the NW-trending faults; then reactivation of the NE trending faults. This intact rhombic conjugate fault system presents new insights into mechanisms of dihedral angle development, with particular relevance to intracratonic basins. 相似文献
17.
Fracture-fissure systems found at mid-ocean ridges are dominating conduits for the circulation of metallogenic fluid. Ascertaining the distribution area of active faults on both sides of mid-ocean ridges will provide a useful tool in the search for potential hydrothermal vents, thus guiding the exploration of modern seafloor sulfides. Considering the Mid-Atlantic Ridge 20°N–24°N (NMAR) and North Chile Rise (NCR) as examples, fault elements such as Fault Spacing (?S) and Fault Heave (?X) can be identified and quantitatively measured. The methods used include Fourier filtering of the multi-beam bathymetry data, in combination with measurements of the topographic slope, curvature, and slope aspect patterns. According to the Sequential Faulting Model of mid-ocean ridges, the maximal migration distance of an active fault on either side of mid-ocean ridges—that is, the distribution range of active faults—can be measured. Results show that the maximal migration distance of active faults at the NMAR is 0.76–1.01 km (the distance is larger at the center than at the ends of this segment), and at the NCR, the distribution range of active faults is 0.38–1.6 km. The migration distance of active faults on the two study areas is positively related to the axial variation of magma supply. In the NCR study area, where there is an abundant magma input, the number of faults within a certain distance is mainly affected by the variation of lithospheric thickness. Here a large range of faulting clearly corresponds to a high proportion of magmatism to seafloor spreading near mid-ocean ridges (M) value, and in the study area of the NMAR, there is insufficient magmatism, and the number of faults may be controlled by both lithospheric thickness and magma supply, leading to a less obvious positive correlation between the distribution range of active faults and M. 相似文献
18.
走滑断控油气藏作为一种全新类型油气藏,其勘探潜力已初步显现。在对中国三大海相克拉通盆地内部走滑断裂发育特征与控藏作用开展对比分析的基础上,揭示了塔里木盆地、四川盆地、鄂尔多斯盆地内部走滑断裂空间结构与活动特征的相似性与差异性,并结合盆地动力学演化特征探讨了不同盆地内部走滑断裂成因机制,系统分析了三大盆地内部走滑断裂的控藏作用:(1)中国三大海相克拉通盆地内部均发育中小尺度滑移距走滑断裂,普遍具有“纵向分层,平面分段,垂向多期叠加”的空间结构特征。(2)三大克拉通盆地内部走滑断裂体系具有成因、分布和期次的差异性。塔里木盆地内部走滑断裂体系形成时间早,演化时间长,在盆地北部具有“南北对接,东西分区”特征;鄂尔多斯盆地西南缘受燕山期(侏罗纪—白垩纪)陆内挤压影响,形成了北西西向走滑断裂体系;四川盆地受控于二叠纪峨眉山大地幔柱影响,在盆地内部先存基底断裂基础上,形成了北西向、北西西向、近东西向张扭型走滑断裂。(3)中国三大海相克拉通盆地内部走滑断裂对油气成藏和富集具有重要的控制作用。在控储方面,受断裂-流体耦合改造控制,可形成断控缝洞型储集体、断-溶缝洞型或断控裂缝-孔隙型储集体;在控圈方面,在碳酸盐岩地层中可形成断控缝洞型、断溶缝洞型岩性圈闭;在控运方面,走滑断裂产状高陡,可直接沟通烃源岩和储层,构成重要的油气垂向输导体系。 相似文献
19.
Detailed analysis of 3D seismic data shows how hundreds of large scale conical sandstone intrusions interact with a polygonal fault network in the Faroe-Shetland basin. The intrusions were injected upwards during the Late Miocene through polygonally faulted claystones of Eocene–Oligocene age. Three types of interactions are recognized: (1) intrusions that are unaffected by polygonal faults, (2) intrusions partially or fully intruded into fault planes, and (3) intrusions arrested by polygonal faults. Type 2 intrusions are generally thinner, taller and wider, whereas those unaffected by faults are thicker and characterized by low dips of intrusive limbs (wings). It was found that Type 2 intrusions preferentially intruded into faults striking NW–SE, whereas Type 3 intrusions were arrested by faults striking NE–SW. Comparison of structural data and simple mechanical predictions allows paleostresses to be reconstructed at the time of intrusion. We have established that the basin was undergoing anisotropic horizontal stresses at the time of intrusions in which σH and σh were oriented N145°E and N055°E, respectively. Intrusion depth, polygonal fault dips and strikes have been used to quantify paleostress intensity and to give a σH/σV ratio close to 0.95 and a σh/σH ratio of 0.8. These ratios support the conclusion that sandstone intrusion emplacement occurred just after a Mid-Late Miocene SSE–NNW (N145°E) compressional phase when the compression direction had decreased in intensity and became smaller than lithostatic stress (σv). 相似文献
20.
《International Geology Review》2012,54(2):133-144
The Wagner basin occupies the northernmost spreading centre in the Gulf of California, located along the Pacific‐North America plate boundary. It is filled with sediments from the Colorado River that obscure its bathymetric expression; therefore it is not as well defined as other basins in the central and southern Gulf of California. To define the geometry and extension of the Wagner basin, a 2D multi‐channel seismic reflection database was used. Data were collected by Petroleos Mexicanos (PEMEX) in 1979–1980. The most important regional structural features identified are the Consag and Wagner normal faults and the Cerro Prieto strike‐slip fault. These structures play an important role in the development of the basin. The Consag fault, described for the first time in this paper, marks the western side of the basin. The eastern and northwest limits are bound by the Cerro Prieto and Wagner faults respectively. The Wagner fault intersects the Cerro Prieto fault at an angle of 130°, bending the depocentre in a NW direction, adjacent to the Cerro Prieto fault zone. The northernmost segment of the Consag fault bends 25° in a NE direction and joins the Cerro Prieto fault at an angle of 110°. Greater subsidence (up to 300 m) takes place along the northern trace of the Cerro Prieto fault, with a downthrown displacement of 400 m. The Consag and Wagner breaks obliquely intersect the Cerro Prieto fault, and, inasmuch as both are normal faults, they have small horizontal slip components which generated oblique displacement. This structural pattern is different relative to the pattern of basins located south of Wagner basin, such as the Upper and Lower Delfin basins. The orientations of the normal faults are perpendicular to the master fault (Ballenas transform fault). The relationship between normal and transform faults in the Wagner basin and the observed ‘S’ shape are typical of a basin that has not yet reached maturity. As a result of this study, the previously uncertain area (～1330 km2) and perimeter (158 km) of the Wagner basin were defined. 相似文献