湘鄂地区海相地层36口井的钻探效果

<正> 湘鄂地区属中扬子区,是南方海相油气勘探的重要领域之一。总面积6×10~4 km。湘鄂地区勘探三十余年,共钻探井41口,其中5口井工程报废,其余36口探井的基本情况和位置见图1和表1。表1中:类型Ⅰ的井钻达上古生界;类型Ⅱ的井钻达下古生界及震旦系。Ⅱ_1型为生储盖组合不全;Ⅱ_2型为生储盖     

中国南方古生界-中生界油气藏成藏规律及勘探方向

中国南方古生界—中生界古油藏主要分布于黔中—雪峰 -江南隆起北侧 (以下古生界及上震旦统灯影组古油藏为主 ,其烃源主要是下寒武统 )及南盘江—十万大山地区上古生界及下三叠统台地及孤立台地边缘 (主要是上古生界及下三叠统自生自储型古油藏 ) ;现存古生界—中生界油气藏主要分布于四川盆地。根据南方多期构造改造及油气演化复杂性的特点 ,将南方古生界—中生界油气藏分成原生、次生及再生烃油气藏 3类。认为南方现存的古生界—中生界原生油气藏很少 ,绝大部分原生油气藏均已破坏成为古油藏 ,四川盆地现存的大多数油气藏是典型的次生油气藏。提出次生气藏有利勘探领域有川东南及大巴山前缘上石炭统—下三叠统、乐山 -龙女寺隆起东南斜坡上震旦统灯影组及下古生界、川西北地区及楚雄盆地北部凹陷上三叠统—下侏罗统煤成气藏 ,再生烃油气藏有利勘探地区有苏北盆地阜宁—盐城—海安—兴化—宝应地区、江汉盆地沉湖地区南部潜江—仙桃—牌州—汊参 1井地区及江西鄱阳盆地南部凹陷。这一认识已经得到苏北盆地盐城凹陷朱家墩气田、川东方斗山背斜带寨沟湾石炭系气田及江汉盆地沉湖地区南部开先台西油藏勘探发现的证实。     

下扬子地区重建型海相烃源油气领域评价及勘探对策

下扬子及邻区的岩石圈演化经历了五个阶段:太古宙古陆核形成期;元古宙下扬子板块形成期;古生代南方古陆形成期;中生代南、北陆拼贴期;中—晚燕山运动以来的大陆边缘离裂期。其中的第三个阶段即古生代南方古陆形成期是下扬子地区海相油气领域的形成期,海相中—古生界厚度可达上万米,含三套生烃岩系,厚度大,叠合连片,原始生烃条件属于一流,且有两大套区域性盖层,形成下古和上古两套成油气组合。在中生代南、北陆拼贴期,上述原生海相油气领域遭受重创,但主要是对当时已形成的油气系统的破坏,对烃源岩的破坏不是太严重,大部分生烃潜力得以保存,这为喜马拉雅期重建型海相烃源油气领域的形成保存了基础,这也是下扬子地区海相油气勘探的前提。对下扬子地区重建型海相油气领域可划分出五种类型:陆相中一新生界覆盖型:火山岩覆盖型;推覆体上盘覆盖型;龙潭煤系致密砂岩含油层领域;龙潭煤系煤层气领域。下扬子地区重建型海相烃源油气领域属于大盆地的范畴,其中最主要的是陆相中一新生界覆盖型,但这是一个极为复杂的油气领域。文中对勘探思路、勘探部署、综合研究、方法攻关及老资料利用等多个方面提出了具体的意见和建议。     

下扬子区海相中、古生界地质结构分区及其油气勘探选区意义

基于对下扬子区海相中、古生界构造及沉积沉降特征的研究, 以影响和反映构造稳定及晚期生烃的基底性质、构造变形特征、印支面埋深、沉积沉降中心迁移特征等为依据, 将下扬子区划分为5个一级、17个二级地质结构区。以构造稳定、有效保存及晚期生烃、晚期成藏等为评价标准, 综合评价南黄海中部晚期隆起稳定区(Ⅰ₂)、江都-东台-南黄海南部晚期沉降深冲断区(Ⅰ₃)、泰兴-海安晚期沉降深冲断区(Ⅱ₁)、南通-南黄海南部晚期沉降浅推覆区(Ⅱ₂)及太湖晚期沉降浅推覆区(Ⅱ₄)为下古生界油气勘探有利区; 南黄海北部晚期沉降深冲断区(Ⅰ₁)、江都-东台-南黄海南部晚期沉降深冲断区(Ⅰ₃)、滨海-大丰晚期沉降深下古卷入区(Ⅰ₄)和泰兴-海安晚期沉降深冲断区(Ⅱ₁)为上古生界油气勘探有利区; 南黄海北部晚期沉降深冲断区(Ⅰ₁)、滨海-大丰晚期沉降深下古卷入区(Ⅰ₄)、金湖-高邮晚期沉降深下古卷入区(Ⅰ₅)及泰兴-海安晚期沉降深冲断区(Ⅱ₁)为古潜山油气勘探有利区。研究对于该区海相中古生界勘探选区具有重要意义。      

中东地区古生界油气分布规律及成藏主控因素分析

古生界是中东地区重要的天然气和轻质原油勘探层系,阿拉伯板块构造--沉积演化为古生界油气聚集成藏提供了有利的石油地质条件。分析认为,前寒武纪—寒武纪早期Huqf群和志留纪Qusaiba段两套优质成熟的烃源岩、多套有利的储盖组合以及一系列大型基底隆起或盐拱成因背斜、断背斜圈闭控制着古生界油气的分布,构成了古生界Huqf和Qusaiba两套主要的含油气系统,每套含油气系统均包括多个油气成藏组合。受早期继承性古隆起和盐构造、有利储盖组合以及断裂通道3个主控因素的影响,古生界油气成藏以下生上储侧向+垂向断裂输导运聚成藏模式为主。     

在1996年南方油气勘探工作会议上的讲话(主要部分) 努力实现南方海相油气勘探重大突破

南方地质条件有四方面的特点:碳酸盐岩区与特提斯域有关,具有良好的含油气前景;叠置在碳酸盐岩区上的南、北两大前陆盆地带,对古生界原型盆地烃源岩的演化、油气藏形成和保存起到重要作用;南方海相地层具有丰富的烃源岩;后期多旋回构造运动,使南方海相油气系统变得十分复杂。南方油气选区评价的关键是保存条件,在含油气系统中“保存单元”是优选勘探目标的重要依据。“九五”期间,一要主攻中、下扬子区,获重大突破;二要积极做好滇黔桂地区三个盆地(南盘江盆地、楚雄盆地、十万大山盆地)的预探;三要进一步搞好区域评价。     

阜阳地区古生界层序地层特征

在综合研究岩石地层资料和测井曲线特征的基础上，对阜阳地区古生代沉积相进行了分析，并对地层层序作了进一步的的划分。整个古生界的沉积演化可看成是一个完整的巨型海进海退旋回。由下古生界和上古生界两个超层序组成。下古生界超层序以频繁的海侵和高水位沉积体系发育为特征，可以进一步划分为6套三级层序，整体为碳酸盐岩台地。上古生界超层序在缓慢抬升的区域构造背景下，表现为一个逐渐海退的沉积序列，缺失下石炭系，可划分为4套三级层序，主要为海陆交互相的含煤碎屑岩沉积。在上述三级层序中，早古生代第一、第五层序和晚古生代第一层序为Ⅰ型层序，其余皆为Ⅱ型。     

下扬子地区海相盆地演化及油气勘探选区评价

从晚震旦世开始至中三叠世,下扬子地区沉积了三套巨厚的海相烃源岩系(Z2-O3、C-P、T1).三套烃源岩热演化特点不同,下古生界烃源岩经历了加里东、印支-燕山期构造阶段的热演化(已达过成熟干气阶段);上古生界烃源岩基本处于生油阶段晚期;三叠系大部烃源岩处于成熟生油阶段,少数处于未成熟阶段.区内下古生界烃源岩经历了两次成油过程,即加里东运动前的盆地沉降阶段和加里东运动后晚古生代陆表海沉积阶段.海相油气储盖条件发育,配置有利,经多年油气勘探证实,下古生界油气勘探应立足于苏北地区;上古生界油气勘探除苏北地区外,尚有皖南与浙西地区.中生界海相油气勘探应集中在几个发育较好的中生代盆地,如常州、句容、无为、望江等盆地.     

中、下扬子区中、新生代陆内对冲带的形成及解体

中、下扬子对冲带是扬子板块在秦岭-大别-苏鲁中央造山系和江南隆起南北向相向挤压作用下的必然结果.对中、下扬子对冲带的空间构造格局以及中、新生代的形成与解体的揭示有助于了解该对冲带的时空演化以及与南、北两大造山带的响应关系、郯庐断裂南端的性质以及区内海相油气的宏观勘探方向.研究认为中扬子对冲过渡带与下扬子对冲过渡带在印支一燕山早期基本同时形成,向西过渡到上扬子区以递进变形的方式稍晚定型.对冲带在燕山晚期以来遭受伸展作用的改造,逐渐解体和分异.郯庐断裂南端介于中、下扬子闻,基于中、下扬子对冲带的完整性和连续性判断断裂南延可能性较小.中、下扬子对冲带是海相油气成藏的有利地区,是南方海相油气勘探潜在的领域之一,但对冲带不同段油气成藏具有较大的差异性和复杂性.     

中国南方海相含油气保存单元的层次划分与综合评价

以最近十年中国南方的海相新区油气勘探评价成果为依托 ,以油气成藏和整体封闭保存体系评价为核心 ,在渝东—湘鄂西、中下扬子和滇黔桂三大区域划分出 9个有利区块 5 1个含油气保存单元 ,并将其归纳为四个层次。综合评价认为 ,方西和石柱保存单元具有较好的整体封存体系 ,属持续性含油气保存单元 ,为首选勘探目标 ;江汉盆地南部、句容—海安区块、南鄱阳坳陷、楚雄盆地东北部具备或基本具备整体封存条件 ,属于沉积重建型含油气保存单元 ,通过精细勘探可望获得商业性油气流 ;楚雄盆地西北部、南盘江坳陷、十万大山盆地和渝东—湘鄂西地区利川复向斜由于晚期强烈构造改造而仅存在部分封存体系 ,需要攻关探索 ;思茅、渝东—湘鄂西地区的花果坪和桑植—石门地区已失去整体封闭保存条件 ,仅局部存在封存体系 ,地质条件高度复杂 ,勘探风险甚高。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861