海拉尔盆地牧原凹陷油气勘探前景与有利区带目标优选          下载免费PDF全文

易立 《中国地质调查》2014,6(4):104-111

牧原凹陷是海拉尔盆地群中研究程度和勘探程度均较低的凹陷,尚未取得勘探突破。为明确牧原凹陷的油气资源潜力与勘探前景,开展了野外地质调查、老井复查与烃源岩有机地球化学特征研究等,基本明确了凹陷油气地质条件: ①牧原凹陷具有单断箕状结构,可划分为陡坡带、洼槽带和缓坡带3个构造单元; ②发育大磨拐河组、南屯组和兴安岭群3套有效烃源岩,南屯组、大磨拐河组烃源岩厚度大,分布面积广,有机质类型好,以II₁-I型为主,有机质丰度高,生烃潜量大,热演化进入成熟阶段,是凹陷主力烃源岩,兴安岭群烃源岩有机质丰度高,处于高成熟阶段,虽然厚度与分布有限,也是一套有价值的烃源岩; ③发育兴安岭群的自生自储或上生下储、大磨拐河组与南屯组的自生自储、伊敏组的下生上储3套储盖组合。对比高勘探程度区单断箕状凹陷的成藏规律,结合牧原凹陷自身的地质特点,构建了牧原凹陷油气成藏模式。通过开展区带的初步评价,优选出2个有利区带,提出了勘探目标。  相似文献   

A 2000-yr reconstruction of air temperature in the Great Basin of the United States with specific reference to the Medieval Climatic Anomaly   总被引：1，自引：0，他引：1  

Scott A. Reinemann  David F. Porinchu  Glen M. MacDonald  Bryan G. Mark  James Q. DeGrand 《Quaternary Research》2014

A sediment core representing the past two millennia was recovered from Stella Lake in the Snake Range of the central Great Basin in Nevada. The core was analyzed for sub-fossil chironomids and sediment organic content. A quantitative reconstruction of mean July air temperature (MJAT) was developed using a regional training set and a chironomid-based WA-PLS inference model (r²_jack = 0.55, RMSEP = 0.9°C). The chironomid-based MJAT reconstruction suggests that the interval between AD 900 and AD 1300, corresponding to the Medieval Climate Anomaly (MCA), was characterized by MJAT elevated 1.0°C above the subsequent Little Ice Age (LIA), but likely not as warm as recent conditions. Comparison of the Stella Lake temperature reconstruction to previously published paleoclimate records from this region indicates that the temperature fluctuations inferred to have occurred at Stella Lake between AD 900 and AD 1300 correspond to regional records documenting hydroclimate variability during the MCA interval. The Stella Lake record provides evidence that elevated summer temperature contributed to the increased aridity that characterized the western United States during the MCA.  相似文献   

Diagenesis in the Middle Jurassic Khatatba Formation sandstones in the Shoushan Basin,northern Western Desert,Egypt     

Mohamed R. Shalaby  Mohammed H. Hakimi  Wan Hasiah Abdullah 《Geological Journal》2014,49(3):239-255

The Middle Jurassic Khatatba Formation acts as a hydrocarbon reservoir in the subsurface in the Western Desert, Egypt. This study, which is based on core samples from two exploration boreholes, describes the lithological and diagenetic characteristics of the Khatatba Formation sandstones. The sandstones are fine‐ to coarse‐grained, moderately to well‐sorted quartz arenites, deposited in fluvial channels and in a shallow‐marine setting. Diagenetic components include mechanical and chemical compaction, cementation (calcite, clay minerals, quartz overgrowths, and a minor amount of pyrite), and dissolution of calcite cements and feldspar grains. The widespread occurrence of an early calcite cement suggests that the Khatatba sandstones lost a significant amount of primary porosity at an early stage of its diagenetic history. In addition to calcite, several different cements including kaolinite and syntaxial quartz overgrowth occur as pore‐filling and pore‐lining cements. Kaolinite (largely vermicular) fills pore spaces and causes reduction in the permeability of the reservoir. Based on framework grain–cement relationships, precipitation of the early calcite cement was either accompanied by or followed the development of part of the pore‐lining and pore‐filling cements. Secondary porosity development occurred due to partial to complete dissolution of early calcite cements and feldspar. Late kaolinite clay cement occurs due to dissolved feldspar and has an impact on the reservoir quality of the Khatatba sandstones. Open hydraulic fractures also generated significant secondary porosity in sandstone reservoirs, where both fractures and dissolution took place in multiple phases during late diagenetic stages. The diagenesis and sedimentary facies help control the reservoir quality of the Khatatba sandstones. Fluvial channel sandstones have the highest porosities and permeabilities, in part because of calcite cementation, which inhibited authigenic clays or was later dissolved, creating intergranular secondary porosity. Fluvial crevasse‐splay and marine sandstones have the lowest reservoir quality because of an abundance of depositional kaolinite matrix and pervasive, shallow‐burial calcite and quartz overgrowth cements, respectively. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Sedimentary stylolite networks and connectivity in limestone: Large-scale field observations and implications for structure evolution     

《Journal of Structural Geology》2014

Stylolites are rough surfaces, formed by localized rock dissolution, and prevalent in carbonates and other sedimentary rocks. Their impact on porosity and permeability, and capacity to accommodate compactive strain, are well documented. This paper presents a meso-scale field study on sedimentary stylolites in carbonates, characterizing large-scale distributions of stylolites, including measurements conducted on longer than kilometer-long stylolites. Our field study suggests that on large scales connections between stylolites become important. Since connectivity, and also lack of connectivity, are expected to play a significant role in strain accommodation and hydraulic rock properties, we suggest that large-scale analysis may require a new characterization scheme for “stylolite populations”, based on their connectivity. We therefore divide sedimentary stylolite populations into three end-member types, which are correlated with the three possibilities for percolation of such systems: isolated stylolites (with zero percolation/connectivity), long-parallel stylolites (with 2-dimensional percolation/connectivity), and interconnected stylolite networks (with 3-dimensional percolation/connectivity). New statistical parameters and measures are devised and used to quantitatively characterize the different population types. Schematic mechanistic models are then offered to explain the evolution of the three end-member connectivity-classes. In addition we discuss the effect on fluid flow of the different population types.  相似文献   

塔里木盆地西南部麦盖提斜坡构造演化过程的 记录——生长地层及生长不整合   总被引：2，自引：0，他引：2  

吕明  汤良杰  岳勇 《地质论评》2014,60(1):91-101

根据塔里木盆地西南部麦盖提斜坡生长地层的发育模式,并结合不整合类型及发育特征的变化规律,探讨了麦盖提斜坡的构造演化过程。认为在早古生代时期,麦盖提斜坡为一北倾的斜坡,构造高点位于斜坡南部;晚古生代,麦盖提斜坡的构造演化过程具有明显的分段性,斜坡西段主要的构造演化时期始于早石炭世,并持续至早二叠世,构造高点迁移至斜坡中部,呈现出"中间高、两头低"的古构造特征;而斜坡东段的主要构造演化时期推迟至晚二叠世。新生代,麦盖提斜坡已反转为南倾的斜坡,构造高点已迁移至斜坡北部,斜坡东段从前中新世开始进入构造演化时期,而西段则推迟至中新世,且东段的构造活动强度要大于西段。  相似文献   

羌塘盆地白垩系海相油页岩特征及其形成条件分析   总被引：2，自引：0，他引：2  

曾胜强  王剑  付修根  冯兴雷  陈文彬  孙伟 《地质论评》2014,60(2):449-463

近年来,在羌塘盆地胜利河、长梁山、长蛇山、托纳木等地发现的油页岩为目前我国规模最大的海相油页岩矿床,具有重要的工业开采价值。海相油页岩的主要矿物成分为碳酸盐、粘土矿物和石英,并见有黄铁矿、石膏、菱镁矿等矿物。粘土矿物以伊利石为主,少量高岭石,不含蒙脱石。有机地球化学分析表明,这些油页岩的有机质丰度较高,有机质类型较好。胜利河油页岩TOC含量在4.31%~21.37%之间,均值为8.40%;托纳木油页岩的TOC含量也较高,最大值为25.68%,平均为9.32%;长梁山剖面油页岩的TOC含量在2.96%~23.47%之间,平均值为9.56%;长蛇山油页岩的TOC含量在4.53%~9.49%之间,平均值为7.74%。长蛇山油页岩干酪根类型主要为Ⅱ1型,少数为Ⅱ2和Ⅲ型;胜利河油页岩主要为Ⅱ1和Ⅱ2型干酪根,而托纳木油页岩的干酪根类型主要为Ⅱ1型和Ⅰ型。白垩系海相油页岩的形成受多方面因素控制,包括缺氧富氧状态、古生产力、古气候、粘土矿物的混积作用、古地形条件以及海平面变化等。其中,油页岩的总有机碳含量(TOC)与古环境元素指标Mo、V存在较强的相关关系,相关系数分别为0.975和0.917,而与古生产力指标P/Ti、Ba/Al之间为弱相关或无相关关系,相关系数分别为0.481和-0.739。因此,本文认为海相油页岩的形成以"保存模式"为主,有机质沉积时的水体环境对高有机质含量的油页岩的形成起主导作用,并在此基础上建立了海相油页岩的形成演化模式。  相似文献   

柴达木盆地西部油族划分及成因研究     

王强  王飞宇  陈琰  冯伟平  袁莉 《地球化学》2014,(2):122-130

对柴达木盆地西部各油田的151个原油进行了分子地球化学分析,并选取伽马蜡烷/C30藿烷、升藿烷指数、甾烷C27/C29和三环萜烷/C30Hop四个参数作为变量进行SAS聚类分析。结合常规二维散点图法,柴西原油可以分为3个油族7个亚族：油族Ⅰ以强水体分层、强还原环境为特征,主要分布于西端的七个泉、红柳泉地区,该油族可以分为两个亚族,油亚族②相比于油亚族①具有更高的甾烷 C27/C29比值;油族Ⅱ主要分布于狮子沟、花土沟、跃进和南翼山油泉子地区,在七个泉、红柳泉等地区也有分布,以相对较强的水体分层、还原环境为特征;油族Ⅲ主要分布于东（南）部的切克里克、乌南、绿草滩、咸水泉、跃西和跃进Ⅱ号等地区,以水体分层变差、较还原环境为特征,该油族可以分为3个亚族,其中油亚族⑤则具有异常低的三环萜烷/C30Hop 比值,油亚族⑥具有异常高的甾烷 C27/C29比值,油亚族⑦则具有异常高的三环萜烷/C30Hop 比值。油族空间分布特征受下干柴沟组源岩有机相在空间上的变化制约,下干柴沟组源岩发育时期,自西向东地层沉积速率增大,水体的分层变差、还原性降低,导致陆源输入的增加以及有机质保存条件变差。  相似文献   

准噶尔盆地陆东-五彩湾石炭系烃源岩特征及生烃动力学研究     

颜永何  ;邹艳荣  ;屈振亚  ;蔡玉兰  ;王绪龙  ;潘长春  ;彭平安 《地球化学》2014,(5):502-509

准噶尔盆地陆东-五彩湾地区石炭系具有良好的勘探前景,该地区石炭系烃源岩有机质丰度较高,成熟度范围宽,主要处于成熟-高成熟演化阶段,主要由Ⅲ型有机质组成。在对烃源岩样品进行常规评价的基础上,用开放体系进行了热解实验和动力学模拟,对陆东-五彩湾地区的生烃特征进行了研究,尝试了高成熟烃源岩生烃过程研究及Ⅲ型干酪根液态烃排烃时间的估计,并对石炭系地层产烃率进行了计算。结果显示,陆东-五彩湾地区石炭系最早在二叠纪（距今264 Ma左右）开始生烃,后期由于地层抬升,在古近纪早期（距今61 Ma左右）结束生烃。下石炭统产烃率大,液态烃排出时间估计在距今232~196 Ma之间;上石炭统产烃率较小,液态烃排出时间估计在距今196~178 Ma 之间,但天然气生成相对较晚,有利于天然气的保存。天然气可能主要来源于上石炭统烃源岩。  相似文献   

三塘湖盆地二叠系干酪根热模拟气体产物的地球化学特征     

杜军艳  程斌  廖泽文 《地球化学》2014,(5):510-517

针对三塘湖盆地的主力烃源岩二叠系芦草沟组泥质烃源岩开展封闭体系和半开放体系热模拟实验,前者将干酪根密封在金管中开展实验、后者直接对烃源岩样品进行压机半开放体系热解模拟,对实验中生成气体的组分和稳定碳同位素进行分析。实验结果显示,两种热解方法以无机气体生成为主,包括CO2、H2、H2S 和 N2等,其中 CO2含量最丰富,这与样品干酪根中丰富的氧含量一致。半开放体系模拟实验温度达到480℃时,气态烃的含量达40.64%,其中甲烷含量达到26.10%,封闭体系中随着模拟温度升高烃类气体产物的碳同位素呈现先变轻后变重的趋势,但同位素分馏程度不大, CH4气体的δ13C 值分布在-40.2‰~-46.6‰之间, C2H6分布在-34.3‰~-38.0‰之间, C3H8分布在-33.6‰~-36.0‰之间,而CO2气体δ13C值分布在-32.8‰~-28.8‰之间。三塘湖盆地针对气藏的勘探已经有所发现,但有关气藏的地球化学特征报道较少,该工作中的模拟实验结果可为三塘湖盆地深入的气藏地球化学勘探提供基础数据。  相似文献   

塔中地区奥陶系喜马拉雅山期S干气充注的证据          下载免费PDF全文

何宏  李红霞  张科  陶小晚  蔡春芳 《地质科学》2014,49(4):1327-1336

塔中地区奥陶系天然气成因多样;Ⅰ号坡折带中东部奥陶系天然气以高干燥系数、 甲烷同位素值重为特征;与塔深1井寒武系原油裂解气接近;应主要来自寒武系原油裂解气成因。寒武系贫H₂S、 高成熟原油裂解气在喜马拉雅山期时;气侵奥陶系油气藏;得到了以下主要证据的支持: 1）天然气甲烷δ¹³C值大多比Chung et al.（1988）天然气模式甲烷δ¹³C值计算值高3‰以上;2）干燥系数与甲烷δ¹³C值大体上具有正相关关系;3）天然气干燥系数与H₂S含量大体上具有负相关关系。这些特征表明;存在贫H₂S、 相对富¹³C甲烷为主的干气与富H₂S、 相对贫¹³C甲烷的湿气混合作用。奥陶系中H₂S-δ³⁴S 值为14‰～20‰;远低于中深1井寒武系原地热化学硫酸盐还原作用（TSR）成因的H₂S（33‰）;支持了奥陶系中H₂S并不是来源于寒武系古油气藏。于是提出;来自寒武系贫H₂S的干气在喜马拉雅山期对良里塔格组和鹰山组油气藏发生了气洗;油气藏的气/油比值增大、 导致了原油蜡含量增高、 甲烷δ¹³C值发生正偏移。  相似文献