济阳坳陷车镇凹陷车66块沙三下段精细沉积相分析

根据测井、地震、岩心资料,运用地质综合方法确定济阳坳陷车镇凹陷北部陡坡带砂体成因类型,搞清深水沉积边界。通过岩心观察与描述、地质地震剖面对比以及沉积相平面分布的研究,认为:车66井区沙三下段发育湖底扇、滑塌浊积扇,它们夹持于暗色深水泥岩之中,以内扇沉积为特色,在主水道及水道间堆积了中、细砾岩碎屑流与背景相泥岩。纵向上,沙三下段具有下部富砂、上部富泥的特征;平面上,自北而南由湖底扇内扇碎屑流→中扇颗粒流、浊流变化,沉积相变化具有从近源到远源发展的趋势,表明了物源来自于北部的埕子口凸起。     

鄂尔多斯盆地三叠系延长组长7段浊积扇对油气聚集的控制

鄂尔多斯盆地三叠系延长组长7段为湖盆环境,盆地深湖区以深湖泥岩沉积为背景,普遍发育浊流沉积,沉积范围广、厚度大,近源的先天优势使其成为油气充注的最先储集单元。弄清浊积扇的沉积特征及不同微相形成的砂体对油气聚集具有重要意义。通过野外剖面分析与岩心观察统计,对浊积扇微相进行精细划分,明确浊积岩的形状、展布与沉积特征。根据前人研究成果,将有固定补给水道的浊积扇和无固定补给水道的浊积扇划分为坡移浊积扇和滑塌浊积扇。通过单砂体厚度、浊积岩类型与发育位置的不同,将坡移浊积扇划分为内扇、中扇、外扇3个亚相和主沟道、溢岸沉积等6个微相;滑塌浊积扇相划分出中心扇和边缘扇2个亚相。浊积扇微相的划分及其成因的讨论能够指导测井对有利砂体的解释,区分不同的油气储集体,为寻找有利油气储层的分布提供依据。     

鄂尔多斯盆地南部延长组浊积岩体系及油气勘探意义

鄂尔多斯盆地南部的浊积岩体系主要发育于三叠系延长组长7、长6油层组。按其沉积特征可分为坡移浊积扇和滑塌浊积扇,前者相带发育相对齐全,垂向上多期互相叠加,可划分为:斜坡—槽道—内扇相、辫状水道、辫状水道间、辫状水道前缘—中扇相、外扇相和盆地平原相,后者多呈透镜状夹于较深湖亚相的深灰色泥岩中,相带分异不明显,仅可分为中心相和边缘相。两类浊积扇主要分布在近源斜坡带及远源末梢斜坡带。滑塌浊积岩主要由阵发性的偶然因素诱发而成,规模相对较小,储集物性较差;而坡移浊积扇则与地形坡度的有利配置和较稳定的物源补给有关,其沉积厚度大,分布广,储集物性好,是深湖区岩性油藏勘探的主要目标。     

准噶尔盆地阜东斜坡带深水浊积扇沉积及油气勘探意义

通过对准噶尔盆地阜东斜坡带侏罗系三工河组的岩性组合、粒度分析和地震反射特征等方面的研究,认为储油砂体主要为浊积岩,岩性为灰色泥岩、灰色中砂岩和灰色粗砂岩夹砂砾岩.岩石成份成熟度和结构成熟度均较低,见典型鲍马沉积序列,浊积扇是不稳定三角洲前缘砂质沉积物向坡折带及深水盆地的再分配的结果.研究该区具有多个浊积扇体,其中阜16井已获得低产油气流,说明阜东斜坡带具有良好的勘探前景.     

湖平面变化对王58地区浊积扇形成与演化的控制作用研究

在陆相断陷盆地内,湖平面变化、构造作用等外部因素对浊积扇体的形成与演化有明显的控制作用。以东营凹陷南斜坡王58地区沙四上浊积扇为例,分析了湖平面变化对浊积扇发育的控制作用。湖平面变化控制了沉积物供给,从而控制了扇体的发育期次。研究区纯上4砂组沉积时期,湖平面相对较低,研究区浊积扇体并不发育;浊积扇体发育在纯上2、3砂组沉积时期;纯上1砂组沉积时期,湖平面上升,研究区不再发育浊积扇。海平面变化控制了沉积物供给,控制了浊积扇体的发育类型。在纯上3砂组沉积时期,水体较浅,发育带水道的浊积扇;在纯上2砂组沉积时期,湖水较深,发育无水道的滑塌浊积扇。总之,随着湖平面的变化,王58地区沙四上浊积扇经历了从出现、发展直到消亡的整个过程,并且随着湖平面的变化,扇体由带水道的浊积扇体向元水道的滑塌浊积扇体转变。     

安徽绩溪新元古代海底扇沉积环境分析

研究区位于安徽绩溪县杨溪镇,区内主要发育一套新元古代浅变质碎屑岩系,厚度为639.7 m。碎屑岩以泥岩、泥质粉砂岩、砂岩、含砾砂岩和砾岩为主,发育水平层理,粒序层理,韵律层理等沉积构造,可见鲍马层序Ta、Tc、Td、Te段。碎屑组分以跃移组分为主,含量为35%～58%。地层上段厚为254.8 m,包含粉砂岩、泥质粉砂岩和粉砂质泥岩,水平层理和粒序层理发育,为中扇-外扇扇叶沉积,中段厚为192.5 m,主要为细砂岩、粉砂岩和泥质粉砂岩,砂岩条带广泛发育,属于中扇水道沉积,下段厚为192.4 m,为一套砾岩层,砾石分选较差,砾岩层间夹有粉砂质泥岩,为上扇水道滞留沉积。总体上,形成一套退积的海底扇沉积序列。     

滇东南法郎组含锰地层沉积相分析

滇东南中三叠统法郎组是重要的含锰地层,前人对其沉积环境的认识却存在着深水浊流沉积和浅水潮坪沉积的争议。本文通过对建水-开远地区典型剖面的研究,认为法郎组为浊积扇沉积。法郎组底部为碳酸盐滑塌沉积、碎眉流沉积与泥岩粉砂岩互层,中上部逐渐由外扇渐变为中扇辫状水道和辫状水道间沉积,顶部为内扇补给水道和溢岸沉积。相对海水深度总体表现为在拉丁早期逐渐加深,到拉丁中晚期有逐渐变浅。锰矿层主要发育在底部的碎屑流沉积中,其彤成可能与拉丁早期相对水深的增高有关。     

南襄盆地泌阳凹陷深凹区核三段沉积特征及演化

通过测井、录井、粒度分析资料,结合区域地质资料、前人研究成果、岩心描述和地震反射资料,认为核三段发育辫状河三角洲、近岸水下扇、滑塌浊积扇及湖泊沉积,并进一步识别出5个亚相及6个微相。其中,近岸水下扇发育于研究区西南部和东南部的控边断层处,辫状河三角洲发育于东北部,滑塌浊积扇发育于辫状河三角洲前端的半深湖-深湖区域。近岸水下扇岩性主要为灰白色中、细砾岩,砾石成分复杂,分选差,磨圆程度低。辫状河三角洲发育平行层理、交错层理及冲刷充填构造,垂向上构成间断正韵律,其岩性为浅灰色砾岩、砾质砂岩、砂岩,中-厚层或块状,自然电位曲线和电阻率曲线呈钟形或箱型。辫状河三角洲前缘砂体失稳,产生滑塌,在深湖区形成滑塌浊积扇,其岩性为细砂岩、粉砂岩、泥质粉砂岩,多呈正韵律,发育块状层理、液化变形层理、波状层理及泥岩撕裂屑、槽模、沟模构造等,电测曲线表现为钟形、箱形、漏斗形等。湖泊沉积主要发育于三角洲前缘和近岸水下扇前方的深凹区。从H38-H31研究区经历了水体由深到浅再略加深的沉积演化。     

鄂尔多斯盆地华庆油田延长组长6油层组深水沉积组合特征

华庆地区位于晚三叠世鄂尔多斯盆地湖盆沉积中心,长6油层组沉积复杂,具有多物源控制、深水沉积的特征。主要沉积类型可划分为半深湖—深湖沉积、重力流沉积及深水三角洲沉积。不同流态的流体在不同阶段和位置可以相互转化、相伴出现。在湖退背景下长6发育厚层砂体,成因复杂,主要包括深水三角洲砂体、滑塌砂体、砂质碎屑流砂体和浊积砂体等类型。其中三角洲砂体发育各种交错层理;滑塌砂体多顶底突变,发育滑动面;砂质碎屑流沉积颗粒大小混杂,含泥岩撕裂屑;浊积砂体通常为正粒序,或呈块状。从平面上分析,东北物源控制区主要为进积的三角洲砂体、滑塌砂体夹浊积砂体;西部、西南物源影响区主要为浊积砂体、滑塌和砂质碎屑流砂体;混源区和东北物源体系的前端主要为砂质碎屑流砂体、滑塌砂体和浊积砂体。     

水下扇岩相特征及形成机制

20世纪50年代初期以来，沉积物重力流研究得到沉积学家们的广泛重视，特别是自60年代末期,与沉积物重力流密切相关的水下扇研究成为沉积学领域的热点。通过对国内外大量沉积物重力流及水下扇研究成果的总结，结合我国中新生代陆相断陷盆地水下扇发育的特点，将水下扇的组成岩相划分为基质支撑砾岩相，颗粒支撑砾岩相，砾质砂岩相，块状砂岩相，经典浊积岩相。水下扇的形成机制系重力流成因。内扇以杂基支撑，颗粒支撑砾岩组合为特征；中扇以砾质砂岩、块状砂岩组合为特征；外扇以CDE序及DE序经典浊积岩发育为特征。     

浊流沉积研究的新进展:鲍马序列、海底扇的重新审视

本文在总结前人对浊流沉积研究的基础上,分析前人对浊流与浊积岩、浊流沉积与浊流相模式的对应关系之间的认识,并对鲍马序列进行重新审视。在海底扇研究过程中,鲍马序列已经不能充分反映浊流沉积的全过程。鲍马序列所反应的沉积模式其实是由碎屑流、浊流、底流等多种形式流体组合和改造后的结果,海底扇沉积模式不能笼统归结为浊流沉积作用的结果。在完善重力流、底流等沉积作用的同时,建立一个与沉积作用相互联系的深海沉积系统,以对深海研究提供更好地指导和预测。     

二连盆地白音查干凹陷早白垩世腾格尔组沉积特征及物源探讨

根据岩芯、录测井、地震以及其它分析化验资料,对白音查于凹陷早白垩世腾格尔组的沉积特征、沉积相类型及其分布规律进行了详细研究.结果表明,腾格尔组发育扇三角洲、辫状河三角洲、湖泊和浊积扇4种沉积相类型,扇三角洲分布在北部陡坡带,辫状河三角洲分布在南部缓坡带,从盆地边缘到盆地中心,沉积相由扇三角洲、辫状河三角洲沉积逐渐转变为半深湖-深湖沉积,在三角洲侧翼发育滨-浅湖相沉积,在三角洲前缘、前三角洲以及半深湖中发育浊积扇沉积,整体呈东西洼凸相问、南北隆凹成带的格局,这种沉积格局受盆地周边断层和古地形控制.利用岩石组分和重矿物成分进行物源分析,认为白音查干凹陷沉积物丰要来自凹陷北部的巴音宝力格降起和凹陷南部的赛呼都格凸起方向,并具有多期次、阵发性、近物源的特点,母岩岩性主要为沉积岩,其次为岩浆岩,见少量变质岩.     

惠民凹陷西部早第三纪沙河街组浊积扇及砂岩体沉积特征研究

惠民凹陷是渤海湾地区新生代断陷盆地之一，其西部地区下第三系发育完整。沙三组中、上段发育大量的浊积扇及典型的浊积岩，后者具深湖相、半深湖相泥岩、油页岩韵律，成因上与三角洲沉积体系的形成、演化关系密切。浊积岩砂体是油气聚集的有利地带，构成了研究区重要的油气储集体。本文阐述了区内沙三组中—上段浊积岩分布、发育样式、形成及演化规律。     

Deposits of depletive high-density turbidity currents: a flume analogue of bed geometry, structure and texture

Flume experiments were performed to study the flow properties and depositional characteristics of high‐density turbidity currents that were depletive and quasi‐steady to waning for periods of several tens of seconds. Such currents may serve as an analogue for rapidly expanding flows at the mouth of submarine channels. The turbidity currents carried up to 35 vol.% of fine‐grained natural sand, very fine sand‐sized glass beads or coarse silt‐sized glass beads. Data analysis focused on: (1) depositional processes related to flow expansion; (2) geometry of sediment bodies generated by the depletive flows; (3) vertical and horizontal sequences of sedimentary structures within the sediment bodies; and (4) spatial trends in grain‐size distribution within the deposits. The experimental turbidity currents formed distinct fan‐shaped sediment bodies within a wide basin. Most fans consisted of a proximal channel‐levee system connected in the downstream direction to a lobe. This basic geometry was independent of flow density, flow velocity, flow volume and sediment type, in spite of the fact that the turbidity currents of relatively high density were different from those of relatively low density in that they exhibited two‐layer flow, with a low‐density turbulent layer moving on top of a dense layer with visibly suppressed large‐scale turbulence. Yet, the geometry of individual morphological elements appeared to relate closely to initial flow conditions and grain size of suspended sediment. Notably, the fans changed from circular to elongate, and lobe and levee thickness increased with increasing grain size and flow velocity. Erosion was confined to the proximal part of the leveed channel. Erosive capacity increased with increasing flow velocity, but appeared to be constant for turbidity currents of different grain size and similar density. Structureless sediment filled the channel during the waning stages of the turbidity currents laden with fine sand. The adjacent levee sands were laminated. The massive character of the channel fills is attributed to rapid settling of suspension load and associated suppression of tractional transport. Sediment bypassing prevailed in fan channels composed of very fine sand and coarse silt, because channel floors remained fully exposed until the end of the experiments. Lobe deposits, formed by the fine sand‐laden, high‐density turbidity currents, contained massive sand in the central part grading to plane parallel‐laminated sand towards the fringes. The depletive flows produced a radial decrease in mean grain size in the lobe deposits of all fans. Vertical trends in grain size comprised inverse‐to‐normal grading in the levees and in the thickest part of the lobes, and normal grading in the channel and fringes of the fine sandy fans. The inverse grading is attributed to a process involving headward‐directed transport of relatively fine‐grained and low‐concentrated fluid at the level of the velocity maximum of the turbidity current. The normal grading is inferred to denote the waning stage of turbidity‐current transport.     

辽河盆地大凌河油层湖底扇沉积特征

辽河盆地位于辽宁省南部,渤海湾盆地东北角,是继中生代发育起来的第三纪断陷盆地。分东部凹陷,西部凹陷和大民屯凹陷等二级构造单元(图1)。     

珠江口盆地白云深水扇特征及油气成藏主控因素

揭示中国南海北部珠江口盆地白云深水扇的时空展布和油气成藏规律.无论在理论上、还是在向深海进军的油气勘探实践上都具有十分重要的意义.以层序地层学理论为指导的地震剖面精细解释,在白云凹陷北部陆坡区发现了大量深水扇沉积体,它由众多的盆底扇、斜坡扇、低位楔和下切水道构成.盆底扇和斜坡扇多期叠加,平面上成朵叶状,并与下切水道相连.研究表明,白云深水扇成藏的主控因素包括:(1)白云凹陷具有适合油气生成的活跃烃源岩;(2)拥有包括断层、不整合面、连续分布的砂体以及流体底辟带在内的发达的输导网络;(3)低水位期发育的深水扇体与其上覆的高水位期泥岩共同形成了有利的储盖组合;(4)超压的累积和释放对深部烃源岩的排烃起到了重要作用.因此,白云深水扇具有良好的成藏条件,是珠江口盆地深水勘探的有利目标.     

东营三角洲-浊积扇高频层序叠加样式与岩性圈闭

东营三角洲砂体及与之伴生的各类浊积扇体是东营凹陷沙河街组三段重要的储油砂体。以高分辨率层序地层学理论为指导,分析基准面旋回变化对三角洲发育演化的控制作用,将三角洲发育过程中的高频层序叠加样式划分为3种类型。通过分析短期基准面的升降变化对与三角洲有关的岩性圈闭形成与分布的影响,指出短期基准面上升期形成的坡移浊积扇圈闭厚度大,分布广,储集物性好,是三角洲发育区岩性油藏勘探的主要目标。该类扇体的分布主要受基准面旋回变化、同生断裂及沉积古地貌等因素所控制,垂向上主要位于中期基准面由下降到上升的转换位置,平面上主要分布于同生断层下降盘及其之间的古地貌低洼处。     

Sedimentary Patterns and Stratigraphic Trap Models of Deeply Buried Intervals in the Baxian Depression, North China

The Baxian depression is a typical half-graben located in the Jizhong sub-basin, north China. Commercial petroleum traps have been discovered in the Jizhong sub-basin. However, the 3rd and 4th members of the Shahejie Formation in this sub-basin have been poorly explored. These two members, belonging to the Lower Paleogene age, are buried deeply in the depression. Favorable petroleum reservoir conditions exist in such deep intervals of the half-graben due to the presence of different types and extent of deltas and turbidity fans in various areas. In fact, three types of turbidite fans are developed in the sag below the transitional belt on the eastern gentle slope. This work summarized three stratigraphic trap belts, i.e., the steep slope, gentle slope, and sag. On the steep slope, structural-stratigraphic traps with small-scale delta fronts and turbidite sandbodies are well developed. On the gentle slope, hydrocarbons generally accumulate in the large-scale delta front, onlapping beds and those sandbodies adjacent to unconformities. In the sag, petroleum trap models are typically characterized by pinched-out turbidite sandbodies. Stratigraphic traps were easily formed in turbidite fans below the eastern transitional belt. The petroleum traps that have already been discovered or predicted in the study area indicate that stratigraphic traps have favorable petroleum exploration potential in deeply buried areas (depth >5000 m) in a half-graben basin or depression.