Callovian-Oxfordian sedimentary microfacies in the middle of Block B on the right bank of the Amu Darya Basin,Turkmenistan

The right bank of the Amu Darya Basin enjoys abundant natural gas resources,on which the Callovian-Oxfordian strata in the middle of Block B serve as the major horizons for natural gas production.However,the characteristics and distribution patterns of the sedimentary microfacies in these strata are yet to be further explored.Based on the analysis of data on drilling,logging,cores,and thin sections from 29 typical wells,as well as the regional sedimentary background,this study inferred that the middle of Block B evolved from the Callovian ramp platform into the Oxfordian rimmed platform.Moreover,this study determined that the inner-ramp intertidal-subtidal shallow-water subfacies mainly developed during the Callovian and transitioned into the shallow shelf subfacies during the Oxfordian.This study identified eight sedimentary microfacies,namely reef knoll,reef-shoal complex,bioclastic shoal,psammitic shoal,bioherm,lime mud mound,intershoal(intermound),and static-water mud.Based on research into the high-precision sequence-sedimentary microfacies framework,this study built a geological model for the development of sedimentary microfacies in the study area.According to this geological model,the sedimentary microfacies in the study area are characterized by vertical alternation of reef-shoal complex,bioclastic(psammitic)shoal,bioherm,and intershoal microfacies.Moreover,they show the development of reef knoll,reef-shoal complex,bioclastic(psammitic)shoal,and bioherm(or lime mud mound)laterally from west to east,with the physical properties of the reservoirs deteriorating from west to east accordingly.The microfacies of reef-shoal complex and the bioclastic(psammitic)shoal predominate in the study area,and their deposition and development are controlled by sequence boundaries and are also affected by paleo-landforms.The Oxfordian reef-shoal complexes were largely inherited from the Callovian uplifts and show lateral seaward progradation.

An intelligent automatic correlation method of oilbearing strata based on pattern constraints:An example of accretionary stratigraphy of Shishen 100 block in Shinan Oilfield of Bohai Bay Basin,East China

Aiming at the problem that the data-driven automatic correlation methods which are difficult to adapt to the automatic correlation of oil-bearing strata with large changes in lateral sedimentary facies and strata thickness,an intelligent automatic correlation method of oil-bearing strata based on pattern constraints is formed.We propose to introduce knowledge-driven in automatic correlation of oil-bearing strata,constraining the correlation process by stratigraphic sedimentary patterns and improving the similarity measuring machine and conditional constraint dynamic time warping algorithm to automate the correlation of marker layers and the interfaces of each stratum.The application in Shishen 100 block in the Shinan Oilfield of the Bohai Bay Basin shows that the coincidence rate of the marker layers identified by this method is over 95.00%,and the average coincidence rate of identified oil-bearing strata reaches 90.02% compared to artificial correlation results,which is about 17 percentage points higher than that of the existing automatic correlation methods.The accuracy of the automatic correlation of oil-bearing strata has been effectively improved.

Formation Mechanism and Sedimentary Pattern of Abandoned Channels

Accurately identifying and quantitatively describing abandoned channels in meandering rivers are of great significance for improving hydrocarbon recovery. By using modern deposition analogy, field outcrop analysis, a dense well spacing, core observations and a review of the literature, this paper studied the formation process and space–time amalgamation of abandoned channels in meandering river. The results reveal that formation mechanisms of abandoned channels include chute cutoff patterns(shoal-cutting, ditch-scouring and embayment-eroding patterns) and neck cutoff patterns. The chute cutoff pattern forms a gradually abandoned channel, while the neck cutoff pattern forms a suddenly abandoned channel. From upstream to downstream, the sedimentary pattern of the abandoned channel transforms from a chute cutoff pattern to a neck cutoff pattern, where the main controlling factors transition from the grain size and gradient to the flow and vegetation. An abandoned channel formed by a chute cutoff pattern consists mainly of siltstone, fine sandstone and thin gravel layers, which form a lithological-physical barrier. The abandoned channel formed by a neck cutoff pattern consists mainly of mudstone and argillaceous siltstone, forming a lithological barrier. Based on the amalgamation and structure of the reservoir architectural elements, the abandoned channel can be divided into three planar sedimentary patterns(crescent, semilune and horseshoe) for a single channel and five vertical sedimentary patterns for composite channels.

Control of paleogeographic pattern on sedimentary differentiation of evaporite-carbonate symbiotic system:A case study of the sixth sub-member of Ordovician Majiagou Formation M5 Member in central-eastern Ordos Basin,NW China

The relationship between paleogeographic pattern and sedimentary differentiation of evaporite-carbonate symbiotic system is examined based on logging,core and thin section data,by taking the sixth sub-member of fifth member of Ordovician Majiagou Formation(M56)in the central-eastern Ordos Basin as an example.(1)Seven sub-geomorphic units(Taolimiao west low,Taolimiao underwater high,Taolimiao east low,Hengshan high,East salt low,North slope and Southwest slope)developed in the study area.(2)The“three lows”from west to east developed dolomitic restricted lagoon,evaporite evaporative lagoon and salt evaporative lagoon sedimentary facies respectively,the"two highs"developed high-energy grain beach and microbial mound,and the north and south slopes developed dolomitic flats around land.(3)The paleogeographic pattern caused natural differentiation of replenishment seawater from the northwest Qilian sea,leading to the eccentric sedimentary differentiation of dolomite,evaporite and salt rock symbiotic system from west to east,which is different from the classic“bull's eye”and“tear drop”distribution patterns.(4)As the Middle Qilian block subducted and collided into the North China Plate,the far-end compression stress transferred,giving rise to the alternate highland and lowland in near north to south direction during the sedimentary period of M56 sub-member.(5)Taolimiao underwater high and Hengshan high developed favorable zones of microbial mounds and grain shoals in south to north strike in M56 sub-member,making them favorable exploration areas with great exploration potential in the future.

Controls of accommodation to sediment-supply ratio on sedimentary architecture of continental fluvial successions

The applicability of sequence stratigraphic models to continental fluvial successions has long been topic for debate. To improve our understanding of how fluvial architectures record responses to changes in the ratio between accommodation rate and sediment-supply rate (A/S), two case studies are analyzed, including a densely drilled subsurface fluvial reservoir imaged with a seismic cube, and an outcropping fluvial succession. The subsurface dataset provides a larger, three-dimensional perspective, whereas the outcrop dataset enables observation at higher resolution. On the basis of both datasets, channel-body density, channel-body stacking patterns and their formative river types are interpreted at different scales, and how these may reflect responses to A/S change (the rate of accommodation creation relative to the rate of sediment supply) are discussed. The results indicate that (i) channel-body stacking patterns undergo four evolutionary stages along with the A/S increase, i.e., multi-story, mixed multi- and two-story, two-story, and isolated patterns;(ii) channel-body density decreases along with the channel-body stacking patterns varying from multi-story to isolated;(iii) formative rivers types are interpreted as evolving from braided planforms to braided-meandering planforms and then to meandering ones, with the increase of A/S.

Pliocene hyperpycnal flow and its sedimentary pattern in D block of Rakhine Basin in Bay of Bengal

Based on core,logging,lab test and seismic data,sedimentary characteristics and pattern of marine hyperpycnal flow,the distribution rules of hyperpycnal flow reservoir,prediction method of favorable hyperpycnal flow reservoir zones,hydrocarbon accumulation model in hyperpycnal flow reservoir in D block of Bay of Bengal were investigated,and the favorable exploration zone and well sites were predicted.Pliocene in D block has typical hyperpycnal flow sediment,which is a set of fine-medium sandstone held between thick layers of marine mudstone and features a series of reverse grading unit and normal grading unit pairs.The hyperpycnal flow sediment appears as heavily jagged box shape,bell shape and tongue shape facies on log curves with linear gradient,and corresponds to multiple phases of deep channels on the seismic section and high sinuous channel on stratal slices.The sedimentary bodies formed by a single phase hyperpycnal flow which include five types of microfacies,namely,supply channel(valley),channel complex,branch channel,levee and sheet sand.The hyperpycnal flow sediments appear in multiple branches,multiple generations and stages in space,forming high-quality reservoirs in strips on the plane and superposition vertically,with fairly good physical properties.The channel complex sandstone,with large thickness,coarse particle size and good physical properties,is the most favorable exploration facies.Based on the guidance of the sedimentary model,distribution of the channel complex microfacies was delineated in detail by seismic reflection structure analysis,spectrum waveform characteristic analysis,slice and attribute fusion,and combined with the structural feature analysis,the favorable drilling zone was sorted out,effectively guiding the exploration deployment of the block.

库车坳陷侏罗系腐殖煤三环萜烷异常分布原因探究

三环萜烷类化合物普遍存在于各类原油与烃源岩中,具有较强的抗生物降解能力及环境指相意义。通过地球化学分析手段对库车坳陷10个腐殖煤样品进行分子化合物研究,发现库车河剖面与卡普沙良河剖面腐殖煤三环萜烷的分布模式差异迥然,库车河剖面主要分布模式为“C_(19)下降型”(C_(19)>C_(20)>C_(21)<C_(23)),卡普沙良河剖面主要分布模式为“C_(21)主峰型”(C_(19)<C_(20)<C_(21)>C_(23))与“C_(23)主峰型”(C_(19)<C_(20)<C_(21)<C_(23))。研究还发现库车河剖面与卡普沙良河剖面腐殖煤成熟度存在明显差异,成熟度的增长会引起三环萜烷的总量上升以及单个三环萜烷化合物绝对量的变化,但在一定成熟度范围内(镜质体反射率(R o)<1.5%),三环萜烷分布模式不发生改变。卡普沙良河剖面腐殖煤三环萜烷分布模式的变化主要受还原环境以及海侵作用引起的细菌等微生物对高等植物的生物改造及低等水生生物输入的影响。

中国典型陆相盆地细粒沉积环境和岩相特征

细粒沉积环境和岩相时-空分布规律是控制页岩油富集高产的主要因素。在前人细粒沉积环境和岩相研究的基础上,分析研究了松辽、渤海湾、鄂尔多斯和准噶尔等中国典型陆相盆地的细粒沉积环境及主要特征。研究认为:①淡水-微咸水湖盆发育粉砂质纹层、黏土质纹层、有机质纹层的黏土岩、粉砂岩以及二者之间过渡岩性,咸水湖和盐湖多发育具方解石(白云石)纹层及黏土级灰泥纹层的细粒碳酸盐岩和细粒混积岩。②陆相湖盆不同演化阶段发育不同细粒岩相组合。裂陷期细粒沉积岩以富碳酸盐矿物的岩相组合发育为特征,拗陷期形成的富有机质页岩层系则以长英质+黏土质沉积岩相组合为主。③湖盆泥页岩沉积机制主要为悬浮沉降、风成输入、浊流、异重流和泥质碎屑流。④中国陆相页岩油类型多样且资源丰富,松辽、鄂尔多斯、准噶尔、渤海湾等中生代—新生代陆相盆地是中国页岩油勘探开发的重要领域。⑤未来细粒沉积环境和岩相研究重点发展方向:开展天文旋回研究,建立系统有效的沉积古环境判识参数及标准;建立陆相湖盆页岩型、夹层型和混合型细粒沉积岩岩相分类和沉积模式,有效地预测细粒沉积岩岩相时空分布;开展细粒沉积成因过程物理和数值模拟,研究细粒沉积物物理、化学和生物沉积耦合过程和形成发育机理;关注数据集成与深度挖掘、人工智能大数据与计算机辅助技术,研究细粒沉积物分布规律。

玛湖凹陷及周缘白碱滩组勘探突破与新认识

为明确玛湖凹陷白碱滩组砂体分布规律和油气成藏模式,评价其油气勘探前景,综合钻井、测井、地震、分析化验等资料,系统梳理白碱滩组二段沉积规律和成藏特征。白碱滩组二段为辫状河三角洲—滩坝—浊积扇沉积序列,发育水下分流河道砂、滩坝砂和浊积砂3种不同类型的砂体,辫状河三角洲前缘亚相以河道砂为主,滨—浅湖发育滩坝砂,半深湖—深湖受坡折带控制发育多个浊积扇体,浊积砂呈朵叶状分布,建立了水下分流河道—滩坝—浊积扇的沉积控砂模式。研究区发育9大走滑断裂体系,其中,走滑断裂直通型、走滑断裂伴生型和走滑断裂接力型3种断裂组合能够有效沟通二叠系风城组烃源岩,作为油气垂向高效运移通道,白碱滩组二段整体具有走滑断裂通源、断裂砂体配置控藏和优质储集层富集的成藏模式。

黔西水城区立火锰矿床成因的地质地球化学约束

二叠纪是华南地区重要的锰富集成矿期。本文以贵州省西部水城区立火锰矿含锰岩系为研究对象,分析影响贵州二叠纪成锰作用的岩相古地理,讨论锰质来源及成因、沉积环境及锰沉淀方式。采用光学显微镜、XRF、XRD和ICP-MS对水城立火锰矿含锰岩系、顶板及底板进行矿物组成、主量、微量及稀土元素分析测试。结果表明,该矿床含锰岩系形成于伸展拉张的台地内部裂陷盆地,锰矿石中见重晶石、石膏、天青石、菱锰矿及菱铁矿等热水沉积矿物,发育热水沉积典型纹层状构造及火山活动长石斑晶硅质交代结构,富含Fe、Mn、Co、Ni、V、Mo等热水沉积元素,具有显著Ce/Ce^(*)负异常稀土配分模式。Mn/Fe、SiO_(2)/Al_(2)O_(3)、Al_(2)O_(3)/TiO_(2)、Co/Ni、Co/Zn、Y/Ho比值及Fe-Mn-(Cu+Co+Ni)×10、Co-Ni-Zn、Co/Zn vs.(Cu+Co+Ni)、LogU/LogTh及Fe/Ti vs.Al/(Al+Fe+Mn)地球化学图解显示水城立火锰矿是热水沉积成因;V/Cr、V/(V+Ni)及Ce_(anom)特征值指示该锰矿床形成于氧化-弱氧化-弱还原海相沉积环境。综合地质、地球化学特征,该矿床锰成矿作用经历了铁锰氧化物(氢氧化物)初始沉淀及铁锰氧化物(氢氧化物)相转化为菱锰矿相的地质演化过程。

塔里木盆地哈拉哈塘—哈得地区中生界物源转换及沉积充填响应

通过矿物成分分析、砂地比计算、地震属性分析及测井响应特征识别等技术手段,对塔里木盆地哈拉哈塘—哈得地区中生界典型沉积时期的古地貌形态、沉积体系展布、地层及砂体发育特征等进行了研究。研究结果表明:(1)塔里木盆地哈拉哈塘—哈得地区三叠系物源主要来自东北部的天山造山带,其ZTR系数由东北部向凹陷中央逐渐增大;侏罗系和白垩系物源主要来自东南部和南部的昆仑山造山带,其ZTR系数由北部、南部向凹陷中央逐渐增大。(2)三叠纪晚期,随着古特提斯洋的增生,研究区北部天山的隆升强度减弱与南部昆仑山的隆升强度增大是此次物源转换的主要原因。(3)三叠纪,研究区的沉降-沉积中心位于南部,主要发育了一套北东—南西向的辫状河三角洲—深水湖泊沉积;侏罗纪和白垩纪,沉降-沉积中心则跃迁到研究区北部,主要发育了一套南东—北西向和南—北向的辫状河三角洲—浅水湖泊沉积。(4)三叠纪,砂体叠置样式的前积方向主要为北东—南西方向;侏罗纪和白垩纪,砂体叠置样式的前积方向主要为南东—北西方向和南—北方向。(5)三叠系岩性油气藏主要发育于研究区西南部,侏罗系和白垩系岩性油气藏主要发育于研究区西北部和北部。

柴达木盆地西部地区新生代盆地性质

含油气盆地不同阶段的性质对于恢复盆地的演化过程、评价油气资源生储运条件具有重要意义。本文在总结前人关于新生代柴达木盆地西部地区性质与演化研究的基础上,重新解译现有地震剖面,系统地开展了盆地构造几何形态、沉积速率、沉积相、沉积旋回、沉积中心迁移以及盆地内不整合的接触关系等方面研究。研究表明:作为陆内挤压背景下的巨大坳陷,新生代的柴达木盆地西部地区具有几何剖面形态不对称、沉积速率较高但又低于西部典型前陆盆地、过补偿状态下强烈缩短致使沉积中心迁移、沉积-构造反旋回性质明显发育等特点。柴达木盆地西部地区以狮子沟组为界线,前期发育细粒远源沉积,属压陷盆地;后期沉积速率显著增加,粗颗粒沉积发育,具有非典型的类前陆盆地性质,并由周缘山体构造活动及盆地过补偿状态共同控制。

Automatic discrimination of sedimentary facies and lithologies in reef-bank reservoirs using borehole image logs

Reef-bank reservoirs are an important target for petroleum exploration in marine carbonates and also an essential supplemental area for oil and gas production in China. Due to the diversity of reservoirs and the extreme heterogeneity of reef-banks, it is very difficult to discriminate the sedimentary facies and lithologies in reef-bank reservoirs using conventional well logs. The borehole image log provides clear identification of sedimentary structures and textures and is an ideal tool for discriminating sedimentary facies and lithologies. After examining a large number of borehole images and cores, we propose nine typical patterns for borehole image interpretation and a method that uses these patterns to discriminate sedimentary facies and lithologies in reeI^bank reservoirs automatically. We also develop software with user-friendly interface. The results of applications in reef-bank reservoirs in the middle Tarim Basin and northeast Sichuan have proved that the proposed method and the corresponding software are quite effective.

大型红层缓倾岩层滑坡形成机制——以川北断渠滑坡为例

大型缓倾岩层滑坡在红层地区广泛分布,由于滑前迹象不明显,很难做到早期防范。为了探索此类滑坡的风险斜坡判识和早期识别,以四川北部南江县断渠滑坡为例,从孕灾地层沉积相和岩性组合特征、区域地质构造演化和层间剪切带发育特征等角度,分析了该滑坡的形成机制。该滑坡体积约为1153×10^(4)m^(3),主滑方向总体向南(170°),为一特大型缓倾岩层古滑坡。滑坡发育于侏罗系中统沙溪庙组上段和沙溪庙组下段交界部位,是岩性和岩相的转换面。沉积相的组合特征决定了斜坡上硬下软的坡体结构。滑坡位于四川盆地北缘新华向斜北西翼,受到了多期地质构造作用,米仓山南缘前陆盆地盖层底部楔入冲断构造模式产生了上部地层原地掀斜效应,增加了层间机械破碎作用,并且软硬2个系列地层交界处应力更易集中,在孕灾地层上下厚度约80 m范围内共计发育了数10条层间剪切带。在地下水大量参与下,破碎程度高且原岩含大量黏土矿物的层间剪切带被逐渐泥化,为滑坡下滑提供了力学条件。

鄂尔多斯盆地奥陶系马家沟组一段—三段构造沉积演化及其油气地质意义

基于测井、岩心、薄片、地球化学分析,重建鄂尔多斯盆地奥陶系马家沟组一段—三段(简称马一段—马三段)构造-岩相古地理格局,探讨构造沉积演变特征及其油气地质意义。研究表明:①马家沟组底部稳定发育一套穿时的、高自然伽马值段、边缘相泥质白云岩,分布于怀远运动期构造不整合面之上,具有与早奥陶世弗洛期全球海侵可对比的δ13C正漂移特征;②奥陶系马一段—马二段沉积期全球海平面上升、古陆淹没为水下隆起,形成一隆两坳构造格局,中央隆起首次接受沉积;随后马三段沉积期盆外俯冲挤压、盆内隆坳分异,乌审旗—靖边凸起活化;③构造格局演变对沉积古环境产生显著影响,马一段沉积期向西超覆,东部坳陷内海侵封隔形成大规模盐质蒸发潟湖;马二段沉积期持续海侵并沟通广海,环东部坳陷发育大规模颗粒滩,晚期干化收缩形成小规模蒸发潟湖;马三段沉积期受高地封隔影响,向东侧水体渐次分异分别形成云膏质和盐质蒸发潟湖,同时颗粒滩环凹沿高地展布;④马家沟组底部发育烃源岩,马二段和马三段滩相储层环坡展布,源储配置良好,有利于天然气成藏,具有一定勘探潜力。

白狼城地区长2辫状河砂体叠置样式与沉积特征

为研究白狼城地区延长组长2砂体叠置样式及沉积特征,利用野外露头、岩芯和测井相分析辫状河沉积相、砂体连通模式、砂体叠置和沉积模式等。结果表明:白狼城地区长2辫状河主要为河道、泛滥平原亚相,河道亚相可细分为心滩、水道2种沉积微相,发育槽状交错层理、板状交错层理、平行层理、块状层理等;辫状河砂体为叠覆泛砂体,分布范围广、厚度大、连续性强、物性好、非均质性强,心滩与水道相间分布,具有“滩道相间、宽滩窄道”的特征;辫状河河道亚相是辫状河沉积砂体主要区域,水道砂体与心滩砂体相互叠置,两侧泛滥平原亚相为良好的隔夹层,为油气成藏提供良好的盖层。研究结果对白狼城地区辫状河沉积特征及砂体构型具有指导意义,对不同盆地的辫状河沉积研究具有借鉴意义。

川西南部地区下二叠统栖霞阶层序地层特征及岩相古地理

【目的】西接康滇古陆的四川盆地西南部下二叠统栖霞阶近年来展示出良好的勘探潜力,然而针对该地区地层充填规律及古地理格局的观点还并不统一,严重制约了下一步盆内精细的油气勘探和井位部署。【方法】以四川盆地西南部下二叠统栖霞阶梁山组和栖霞组为研究对象,综合利用野外剖面、钻井岩心和测录井等资料,在岩石类型与沉积相分析的基础上,运用海相碳酸盐岩层序地层学原理与方法,对栖霞阶层序界面进行识别。并采用单因素分析多因素综合作图法,以三级层序为编图单位,结合优势相原则,分别绘制研究区栖霞阶SQ0+SQ1和SQ2层序岩相古地理图。【结果】在栖霞阶中识别出4个三级层序界面,从下到上分别为梁山组底界面(I型)、栖一段内部界面(II型)、栖一段\栖二段界面(II型)和栖霞组\茅口组界面(I型),并将其划分为3个三级层序,每个层序均由海侵域和高位域组成。通过层序地层格架的对比分析,认为栖霞阶下部的SQ0层序大致对应于传统划分的梁山组+栖一段下部地层,仅发育于研究区内的栖霞阶地层沉积前古地貌低地,并且具有向古地貌高地超覆的层序充填特征,中部的SQ1层序和上部的SQ2层序则遍布全区。川西南栖霞阶层序岩相古地理格局总体上表现为西接康滇古陆的海相碳酸盐岩台地,古地貌和沉积相带分异比较明显,自西向东依次为:康滇古陆及其东缘的潮坪、台内洼地、台内丘滩体,以及开阔—半局限海台地,而且沿台内坡折带发育的台内丘滩体往往具有环洼规模分布的趋势。【结论】通过剖析台内坡折带对碳酸盐岩成储的影响,指出SQ2层序(栖二段)是研究区栖霞阶最有利于台内丘滩体这一潜力储集相带发育的层位,环台洼坡折带发育的丘滩体相带附近是有利的勘探区。从层序地层学角度重新认识栖霞阶充填模式及岩相古地理特征,为川西南部下二叠统栖霞阶的下一步储层预测及勘探开发提供全新的理论支撑。

渤海湾盆地黄河口凹陷SC7区块古近系东营组二段下亚段滩坝储集体构型特征

渤海湾盆地黄河口凹陷SC7区块滩坝是滨浅湖区的重要储集体,厘清其砂体内部结构特征对油气开发具有重要指导意义。根据现代沉积和岩心、录井、测井资料研究,对SC7区块古近系东营组二段下亚段(东二下亚段)砂体进行构型解剖,将厚泥-薄砂式滩坝划分为坝中心、坝侧缘、内缘滩、外缘滩和湖相泥5种沉积微相类型。基于厚泥-薄砂式滩坝成因和内部结构特征分析,研究了滩坝沉积特征、沉积模式和生长过程。将滩坝构型分为复合砂坝、单一坝和增生体3个级别,探讨各滩坝砂体构型单元空间展布特征。提出了单一坝坝间泥岩、测井曲线特征、相对高程差和单一坝侧向相变4种识别标志。用识别标志对密井网区单一坝进行划分,分析了单一坝规模、演化过程及连通性。在单一坝内部划分出4期增生体,最终确定了4级构型界面、单一坝侧向相变和单一坝内部增生体对油气分布的影响。

海上L区稀疏井网沉积微相刻画研究

海上L区井网稀疏井数少、目标储层地震分辨率差、制约储层沉积微相刻画精度,为解决小层沉积微相刻画难的问题,建立了以沉积模式为指导、单井微相作约束、多地震属性综合对比的沉积微相刻画方法,完成稀疏井网小层沉积微相识别刻画研究,明确工区微相展布特征,相演化模式验证结果可靠。形成的稀疏井网沉积微相刻画方法,为海上稀疏井网储层沉积微相刻画提供参考和借鉴意义。

渤海海域明下段早期区域沉积格局及其勘探意义

新近系是渤海油田增储上产的重要领域,由于缺乏区域沉积体系系统研究,导致规模型砂体发育规律及岩性勘探方向不明。以明下段早期为研究对象,针对高精度地层格架、河-湖分布格局、沉积体系展布特征、规模砂体成因机制等关键问题开展研究。研究首次建立了明下段内部“基于古气候旋回”的区域等时层序格架,为高频相变背景下的沉积体系研究奠定了基础。明确了湖盆萎缩期“平原为主、湖泊伴生”的区域沉积环境格局。确立了“河流相为主、局部河-湖交互”的区域沉积格局,建立了稳定型曲流河、迁移型曲流河、河-湖交互沉积发育模式,明确了不同类型规模砂体的成因机制与分布规律。上述新认识为一系列新近系大中型油田的发现提供了理论支撑,对渤海油新近系未来岩性勘探具有重要的指导作用。