一个典型的寒武系油藏:塔里木盆地塔中62井油藏成因分析

塔里木盆地志留系沥青砂岩广泛发育,主要原因是来源于寒武系的原油在进入志留系储层后区域性的抬升剥蚀使油藏遭到严重破坏,但到目前为止,究竟是寒武系烃源岩还是中上奥陶统烃源岩或是两者都对现今的志留系沥青砂岩中的有机质有贡献还不清楚.对塔中62井原油的化学组成和油源的分析表明,其甾萜类组成具有寒武系烃源岩的组成特征,反映该油藏原油主要来源于寒武系.另一方面,塔中62井砂岩透镜体被泥岩圈闭,油藏具有较好的保存条件,且后期中上奥陶统生成的烃类难以充注进入油藏.塔中62井志留系油藏破坏作用较弱、保存较好,是塔里木盆地在志留系发现的第一例来源于寒武系的油藏.     

Depositional environment and tectono-provenance of Upper Kaimur Group sandstones,Son Valley,Central India

The Mesoproterozoic Upper Kaimur Group consists of Bijaigarh Shale, Scarp Sandstone, and Dhandraul Sandstone. Based on the lithofacies data set, two major facies associations were identified, namely—tidal sand flat/sand bar facies association (TSFA) and tidally influenced fluvial channel facies/tidal channel facies association (TIFCFA). The Dhandraul Sandstone has been interpreted as a product of TIFCFA and the underlying Scarp Sandstone in TSFA which endorses a tidal dominated estuarine setting. Detrital modes of the Dhandraul and Scarp Sandstones fall in the quartz arenite to sub-litharenite types. Petrographical data suggest that the deposition of the Upper Kaimur Group sandstones took place in humid climate and was derived from mixed provenances. The sandstone composition suggests detritus from igneous rocks, metamorphic rocks, and recycled sedimentary rocks. The sandstone tectonic discrimination diagrams suggest that the provenances of the Upper Kaimur Group sandstones were continental block, recycled orogen, rifted continental margin to quartzose recycled tectonic regimes. It is envisaged that the Paleo- and Mesoproterozoic granite, granodiorite, gneiss, and metasedimentary rocks of Mahakoshal Group and Chotanagpur granite–gneiss present in the western and northwestern direction are the possible source rocks for the Upper Kaimur Group in the Son Valley.     

Provenance sources of Upper Proterozoic and Lower Paleozoic clastic deposits of the Lesser Khingan terrane,Central Asian fold belt: U–Pb (LA–ICP–MS) geochronological results

Doklady Earth Sciences - The ages of detrital zircons from sandstones and silty sandstones from conditionally Upper Proterozoic–Cambrian rocks have been obtained for the first time. These...     

Microstructures in the Cretaceous Bima Sandstone,Upper Benue Trough,N.E. Nigeria: Implication for hydrocarbon migration

Faulting related to movements along major fault zones in the Upper Benue Trough during Albian times, with evidence of deformation in the Cretaceous Bima Sandstone are common especially around the Kaltungo, Gombe, Zambuk and Teli lineaments. Conjugate extensional systems of deformation bands show increased siliceous cementation of the sandstones adjacent to these lineaments. During the Late Cretaceous compressional event, the deformation bands and faults in the Upper Benue Trough were reactivated, resulting into dilational opening of fractures believed to have acted as fluid conduits and/or barriers. These deformation bands which decrease in density away from the major faults are characterized with increasing porosity and permeability in the host sandstone abruptly away from the tectonic barrier. It is proposed here that the master faults of the Benue Trough, linking it with the Anambra Basin and the Niger Delta probably served as conduits for the migration of hydrocarbons into the Cretaceous reservoirs of the Upper Benue Trough and by extension into the Niger Delta.     

上扬子地区下寒武统海相富有机质页岩形成环境与主控因素分析

对上扬子地区下寒武统富有机质页岩发育主控因素的研究是进行该区页岩气勘探有利区预测的基础问题之一。通过对上扬子地区下寒武统黑色页岩典型露头剖面样品特征的分析,运用岩石、矿物、有机质特点、特征元素等指标对该区海相富有机质页岩在早寒武世时的古环境进行恢复,建立上扬子地区下寒武统海相富有机质页岩沉积环境判别综合表,认为该套黑色页岩在早寒武世是典型的缺氧环境。上扬子地区下寒武统富有机质页岩的发育是古构造、古气候和古海平面变化、古洋流及海底热液活动等因素综合作用的结果。建立了上扬子地区古海平面上升―上升洋流―热液活动―水体分层―缺氧环境的页岩发育模式,指出海底热液活动和上升洋流促进生物体的勃发,为富有机质页岩形成提供物质基础;海平面上升和上升洋流不仅造成水体分层,而且共同影响富有机质页岩的分布范围。     

东昆仑造山带早古生代—早中生代构造演化的沉积地球化学记录

东昆仑地区发育一套显生宙碎屑岩地层,包括下寒武统沙松乌拉组、中—上奥陶统纳赤台群、上石炭统—下二叠统浩特洛哇组、下三叠统洪水川组、中三叠统希里科特组以及上三叠统八宝山组。研究区砂岩的CIA值反映沙松乌拉组砂岩源区化学风化程度较高,其余各组砂岩源区化学风化程度较低。主量和微量元素研究结果表明各组砂岩源区以长英质岩石为主,包含少量中性成分。La、Ce、Th、U、∑REE含量和La/Sc、Th/Sc、Sc/Cr、La/Y比值指示沙松乌拉组和纳赤台群砂岩沉积环境为大陆岛弧或活动大陆边缘,浩特洛哇组砂岩形成于被动大陆边缘环境,洪水川组砂岩沉积环境为活动大陆边缘,希里科特组砂岩的微量元素含量及其比值接近于活动大陆边缘和被动大陆边缘,八宝山组砂岩沉积环境为活动大陆边缘。综合分析认为沙松乌拉组和纳赤台群砂岩形成于原特提斯洋俯冲阶段,浩特洛哇组砂岩形成于古特提斯洋持续扩张阶段,洪水川组砂岩形成于古特提斯洋俯冲阶段,希里科特组砂岩形成于陆(弧)陆初始碰撞阶段,八宝山组砂岩形成于陆陆全面碰撞—碰撞后阶段。     

从岩石成因论华北地台“霍山砂岩”的时代归属

<正> 霍山砂岩由山根新次(1924)创名于山西中部的霍山,并描述为滹沱系之上的“由红色石英砂岩组成的厚的单一岩层组,底部常常有砾岩……可以作为华北最年轻的前寒武系。”自霍山砂岩创名以来始终存在两种不同的地质时代归属意见。主张归属震旦纪的有     

Facies change in upper devonian and lower carboniferous rocks of Southern Ireland

In south-west Ireland 8,000 ft (2,440 m) of marine sandstones and mudstones, the Cork Beds (?Upper Famennian to E Zone, Carboniferous, in age), overlie the Old Red Sandstone. Farther north the Old Red Sandstone is succeeded by thin Lower Limestone Shales overlain by thick Waulsortian bank limestones. A critical section (North Ringabella) west of Cork Harbour, in which 6,500 ft (1,981 m) of Old Red Sandstone and Cork Beds is exposed, is described and divided into ten formations. By comparison with sections to the south the upper beds of the Old Red Sandstone are shown to pass southward into marine sandstones (Cork Beds) of ?Upper Famennian age. The successions in the Cloyne and Cork Synclines are described and reveal the progressive northward change in the Lower Carboniferous from the argillaceous Cork Facies through a zone of isolated bank limestones (Cloyne) to a thick, 4,000 ft (1,219 m), Waulsortian bank complex (Cork). Finally an attempt is made with use of isopachyte maps to reconstruct the palaeogeography of southern Ireland in Upper Devonian and Lower Carboniferous times.     

地球内部物质物性的原位高温高压研究：大体积压机与同步辐射源的结合

四川盆地是一个大型复合含气为主、含油为辅的叠合盆地。多旋回的沉积演化过程,孕育了多套海相、陆相烃源岩,且不同区域发育不同成因类型的烃源岩。目前下寒武统、志留系、下二叠统、上二叠统和上三叠统五套主要烃源岩均已进入高演化阶段,并以成气为主。由于多阶成烃、混源聚集和后期遭受TSR次生蚀变等成藏过程的复杂性使得天然气组分较干、碳同位素组成复杂,常规方法进行气源对比较困难。文中在对四川盆地沉积演化背景分析的基础上,通过对有效烃源岩发育特征和分布规律的探讨,分区域进行了气藏的分析,特别是对天然气组分、非烃组成(H2S、CO2、N2等)和碳同位素等资料综合研究的基础上,基本确定了各区块各含气层系的主力源岩。认为川东主力产层石炭系、三叠系和二叠系的气源分别为志留系、上二叠统龙潭组和下二叠统;川南气区震旦系灯影组、寒武系、二叠系和三叠系产层的气源分别主要来自下寒武统,上、下二叠系源岩;川西气区侏罗系和三叠系须家河组主产层的气源主要来自三叠系须家河组煤系烃源岩,下二叠统和嘉陵江组产层气源则可能主要来自二叠系;川中主要为产油区,下侏罗统自流井群原油应来自侏罗系源岩,浅部层系气源为上三叠统须家河组的陆相烃源岩,深部气藏则为寒武系烃源岩。由于川东北部烃源岩发育层数最多,且质量都较好,因此川东北部是烃类最富集的地区,也是勘探潜力最大的地区。     

尼日尔Termit盆地上白垩统储层岩石学特征及控制因素分析

本文对尼日尔Termit盆地17口井218个井壁取芯样品开展普通薄片、阴极发光、X衍射、扫描电镜及重矿物分析,研究上白垩统储层的岩石学特征,并探讨其控制因素。实验分析结果表明,Termit盆地上白垩统储层的岩石类型主要为石英砂岩,成分成熟度高,以石英为主,含量达86%以上,钾长石、方解石及斜长石等含少量,占比约5%,这种岩石类型对原生孔隙的保存比较有利;填隙物主要为粘土杂基,含量为7%左右,矿物成分以高岭石为主,利于对晶间孔的保留;岩石中发育硅质、方解石和铁质等胶结类型,胶结物的含量占比较小,对储层的破坏作用不大;重矿物类型为磁铁矿、赤铁矿、锆石、磷灰石,推测物源区的母岩类型主要为花岗岩;以细粒结构和少量的不等粒结构为主,分选中等-差,磨圆度一般为次棱角-次圆状,磨圆差。与国内石英砂岩沉积于高能的滨浅海环境不同,研究区石英砂岩成分成熟度高,但分选程度和磨圆度较低,一方面反映了物源区母岩富含石英,同时也反映了这种石英砂岩沉积于近源的河流-三角洲环境。影响研究区上白垩统储层物性的主要因素是岩石类型及成岩作用,由于储层的岩石类型为石英砂岩,压实作用对储层的破坏作用较一般岩石类型偏小。砂岩埋深小于2500m时,主要发育原生孔隙,面孔率大于15%。溶蚀作用对本区储层产生一定的影响,最常见的为长石的溶蚀,溶蚀作用形成粒内溶孔和粒间溶孔,还会扩大原生孔隙形成混合孔,改善了砂岩的储集性能。     

The Precambrian–Cambrian nonconformity at the Ercall Quarries,The Wrekin,Shropshire, UK

The Precambrian–Cambrian boundary is iconic, marking the first appearance of shelly fauna in the fossil record, and opening the Phanerozoic Eon. In England and Wales, the transition from predominantly Precambrian igneous rocks to Cambrian sedimentary strata is generally unconformable. An exceptional exposure of this transition can be observed in the Ercall Quarries in Shropshire, a classic locality in all senses of the word.     

皖南—浙西下古生界碳沥青成因及南方海相“有效烃源岩”问题探讨

赋存于皖南—浙西的固体碳沥青分为古油藏裂解碳沥青和古油藏破坏次生充填碳沥青两种类型 ,阐明了两类碳沥青的不同成因机制。重新认定了浙西“康山沥青脉”为碳沥青而不是泥岩。论证了皖南、浙西碳沥青的烃源为下寒武统、中—上奥陶统至下志留统、中—上寒武统等。认为加里东运动—广西事件期间是下扬子盆地相区以下寒武统黑页岩为烃源的油藏形成和部分破坏的主要时期。针对南方的油气勘探 ,提出了只有在晚期成藏中作出贡献的源岩才是“有效烃源岩”的新概念。     

First results of U–Pb dating of detrital zircons from the Upper Ordovician sandstones of the Bashkir uplift (Southern Urals)

The first results of U–Pb dating of detrital zircons from Upper Ordovician sandstones of the Bashkir uplift in the Southern Urals and U–Pb isotopic ages available for detrital zircons from six stratigraphic levels of the Riphean–Paleozoic section of this region are discussed. It is established that the long (approximately 1.5 Ga) depositional history of sedimentary sequences of the Bashkir uplift includes a peculiar period lasting from the Late Vendian to the Emsian Age of the Early Devonian (0.55–0.41 Ga). This period is characterized by the following features: (1) prevalence of material from eroded Mesoproterozoic and Early Neoproterozoic crystalline complexes among clastics with ages atypical of the Volga–Urals segment of the East European Platform basement; (2) similarity of age spectra obtained for detrital zircons from different rocks of the period: Upper Vendian–Lower Cambrian lithic sandstones and Middle Ordovician substantially quartzose sandstones.     

黔东南地区震旦系-二叠系海相优质烃源层的时空分布

黔东南典型古油气藏的精细解剖对黔中隆起周缘乃至南方海相油气勘探研究具有重要意义。研究表明,在早寒武世初期、晚泥盆世早期和二叠纪,本地区均发育优质烃源岩,其中以下寒武统盆地相、斜坡相的黑色页岩发育最好,有机质丰度高(TOC普遍大于2%),类型好(偏腐殖型),厚度大,是麻江古油藏及凯里残余油气藏的主力烃源岩;早二叠世盆地相和澙湖相中发育的优质烃源岩与本层位中的沥青具亲缘关系,显示自生自储的特点。二叠纪烃源岩对黔中隆起及其周缘地区油气成藏具有重要作用。本地区缺乏扬子地区广泛发育的上奥陶统五峰组—下志留统龙马溪组底部那套优质烃源岩。     

油气充注对塔中志留系沥青砂岩储集性影响的模拟实验研究

志留系储层原油演化成沥青过程中，沥青充填于粒间孔及填隙物中，占据了孔隙空间，残余孔隙率、渗透率很低。通过模拟实验的方法分析了油气充注对沥青砂岩储集性的影响，早期充填沥青少而残余孔隙率、渗透率很低的砂岩，晚期油气仍不能充注，是非储层；早期沥青均匀充填、充填程度高，残余孔隙率、渗透率低的砂岩，晚期低粘度稀油仍能充注，孔隙率、渗透率有大幅度提高，是有效储层；早期沥青充填较均匀，残余孔隙率相对较高，不同粘度的原油充注后，孔渗条件发生明显的改善。常温的实验表明，原油的物理性质是决定沥青砂岩能否再次充注的关键因素之一，稀油充注是志留系沥青砂岩成藏的必要条件。     

湘西震旦—寒武纪交替时期古海洋环境的恢复

前寒武纪至寒武纪的交替时期是地质史和生命史的重要转折。中国南方地区广泛发育了上震旦统、下寒武统的黑色岩系。文中运用沉积学和沉积地球化学的理论和方法对湘西黑色岩系的岩石类型、矿物组成、元素地球化学特征、干酪根的结构以及碳同位素的组成等方面进行了研究 ,讨论了黑色岩系的形成条件 ,恢复了震旦纪 /寒武纪地史转折期的古环境。研究认为 ,湘西地区在晚震旦世和早寒武世地史转折期的生物爆发和高有机质的产率是形成缺氧环境的重要因素之一。     

The ordovician (caradoc) volcanic rocks of montgomery,Powys, N. Wales

The Ordovician (Caradoc, Soudleyan) rocks of Montgomery, Powys are shales interbedded with locally conglomeratic volcaniclastic sediments composed of andesitic detritus. New formal lithostratigraphic units are proposed: Montgomery Volcanic Group comprising in ascending order: Castle Hill Shale Formation, Castle Hill Conglomerate Formation and Quarry Sandstone and Shale Formation. The volcaniclastic strata are reinterpreted as deposits of a submarine volcaniclastic fan system sourced by contemporaneous andesitic island volcanism. The observed diagenetic sequence is typical of marine volcanic sandstones and was dominated by hydration reactions related to the degradation of abundant unstable volcanic detritus. Diagenesis has resulted in the virtual destruction of original porosity in the volcaniclastic rocks.     

塔里木盆地东部下志留统下砂岩段储层特征

塔里木盆地东部的志留系为一套海相碎屑岩沉积,现今仅保存有下志留统,分布在铁南2井、维马1井以南、阿南1井以北的东西向狭长地带内。下志留统的下砂岩段是油气勘探的主要目的层之一,发育扇三角洲沉积体系。下砂岩段储层岩性为岩屑砂岩,储集空间类型主要为剩余原生粒间孔,压实作用是影响储层物性的主要因素。在下砂岩段储层中,中砂岩的储集性能相对较好,其孔隙度多数在10%以上,是下砂岩段的主要含油气储层。后期的成岩作用改善了局部层段的储层物性。经历了漫长的地质演化后,下砂岩段依然保存有物性条件较好的储层段,可能蕴涵了商业油气储量。     

Facies relationships in the Upper Devonian-Lower Carboniferous of southwest Ireland and adjacent regions

In southwest Ireland 2,500 m of Upper Famennian to basal Namurian marine sandstones and mudstones, the Cork Beds, overlie rocks of Old Red Sandstone facies. Coastal exposures of the Cork Beds are interpreted as showing gradual upward change from alluvial strata, through thick subtidal and shelf sediments to pyritic muds. A review of recent palaeontological evidence shows that the thick shallow marine part of the Cork Beds is older than the major development of lime-stones north of the Cork Harbour—Kenmare Une, whose equivalents to the south are in the condensed basinal sediments. The Lower Carboniferous portion of the Cork Facies is shown to be thicker in South Cork than in West Cork. In Lower Carboniferous times a positive area–the Glandore High–separated two sub-basins with different depositional histories. Six palaeogeographic maps are used to demonstrate the progressive shift of facies belts as Lower Carboniferous marine transgression progressed. Finally, brief comparison is made with rocks of the same age in southwest England.     

塔里木含油气盆地沉积学研究进展

随着近年来塔里木盆地油气勘探的深化,各主要目的层的沉积学研究取得了长足的进展:对轮南-塔河亿吨级油田为代表的奥陶系碳酸盐岩非均质古岩溶储层形成机理认识的进步及其地震识别技术的建立,极大地提高了勘探成功率;近年来油气勘探新突破也展示了轮南奥陶系主风化壳区外围台地边缘区带存在广阔的勘探前景;以哈得4亿吨级油田为代表的上泥盆统-下石炭统东河砂岩滨岸穿时砂体层序地层格架及其分布模式的建立,拓宽了东河砂岩岩性圈闭及岩性-构造复合圈闭油气藏的勘探领域;以英南2气田为代表的侏罗系低孔低渗砂岩储层-含水网状粘土胶结砂岩因水锁效应成为气藏直接盖层的特殊储盖组合的发现,拓宽了天然气勘探领域;以克拉2特大型气田为代表的高压气藏储盖组合(干旱气候下形成的下白垩统巴什基奇克组辫状河三角洲及扇三角洲巨厚砂岩储层-早第三纪海湾-蒸发泻湖环境沉积的巨厚膏盐泥岩优质盖层),在库车及塔西南等地区普遍分布,具有广阔的勘探前景。