A new cheirolepidiaceous conifer from the Early Jurassic of the Junggar Basin, northern Xinjiang and its paleoclimatic implications

Mesozoic sediments are extensively developed in the vast area of Xinjiang and Jurassic strata are well exposed in the Junggar Basin. The Haojiagou geological section near Urumqi in the south of the basin is a typical section for the Lower Jurassic Badaowan and Sangonghe formations. The cheirolepidiaceous conifer Brachyphyllum (Hirmeriella?) sp., which exhibits strongly xeromorphic characters, was discovered in the Sangonghe Formation and is associated with a high relative abundance (up to 75%) of dispersed Classopollis pollen. The occurrence of cheirolepidiaceous foliage and Classopollis pollen in the Sangonghe Formation indicates that a warm and dry climate prevailed in the Junggar Basin during the Early Jurassic (Early Toarcian), supporting the hypothesis for a warming event at that time.     

准噶尔盆地腹部沙漠区煤下储层预测和流体识别技术

准噶尔盆地腹部莫索湾沙漠区侏罗系煤下储层三工河组是主要油气高产层系之一,主要发育构造-岩性复合圈闭,目的层受地表沙漠和西山窑强煤层影响,地震资料信噪比、分辨率低,反射能量弱,储层薄、横向变化快.将地质与地球物理技术有机结合,采用面向目标识别处理技术、岩石物理分析技术、叠前储层预测和流体检测技术,取得了丰富的地震地质结果,为该地区的储量升级提供了保障.     

莫西庄地区三维工区非线性反演与砂体识别

准噶尔盆地中部莫西庄的侏罗系三工河组储层砂体在纵向、横向上变化大,且物性不均匀。本文通过对钻井、测井、试油等地质资料的分析研究,以三维地震资料为基础,采用地震高分辨率非线性三维整体反演方法,对多种参数进行了反演和处理,获得了反映砂岩分布特征的速度、密度及伽马等属性参数的三维数据体,并综合地质资料进行沉积分析、砂岩累计厚度和有效砂岩累计厚度及储层分布研究。通过物性特征分析,建立了识别和评价三工河组砂体的物性标准,利用岩性划分标准和地震多属性数据,提取出三工河组砂体和有利砂体的空间展布特征。三工河组砂岩和有利砂岩发育,并以条带、砂坝和席状砂形式展布,展布方向与区域沉积方向一致。其中三工河组优质储层段J1s21和J1s22厚度较大,具备良好的物性条件,具有较高的产储能力和勘探开发前景。     

滕北煤系上覆地层的孢粉组合及其地层意义

本文根椐腾北煤田煤系上覆地层中发现的生物化石组合,进一步阐述了鲁西南地区晚侏罗世地层的存在,并首次发现了该区零星分布的老第三纪中—晚始新世官庄组沉积,为本区中、新生代地层层序的建立奠定了基础。     

征沙村地区三工河组低渗透砂岩储层孔隙结构研究

低渗透砂岩储层孔隙结构复杂,制约了该类型油藏的高效勘探开发,一直是地质学者研究的关键问题。以准噶尔盆地征沙村地区侏罗系三工河组低渗透砂岩储层为研究对象,利用岩石薄片、铸体薄片、扫描电镜、X射线衍射等微观测试方法,结合常规压汞、恒速压汞及核磁共振等岩石物理分析手段,系统地对孔隙结构进行了综合研究。结果表明:该区低渗透砂岩储层的岩石类型以长石岩屑砂岩为主,储集空间主要为残余粒间孔和粒间溶孔;喉道半径的差别是造成渗透率级差的主要控制因素;核磁共振横向弛豫时间T_2的分布与孔隙半径有较好的对应性,可以有效评价可动流体孔隙特征。研究对本地区的勘探开发具有积极作用,可以应用到其他相似低渗透砂岩油气藏评价中。     

准噶尔盆地莫西庄地区侏罗系三工河组层序地层学研究

应用Vail经典层序地层学的理论和方法,综合利用测井、岩芯、地震、野外露头等资料,对准噶尔盆地莫西庄地区侏罗系三工河组层序边界、三级层序内的最大湖泛面和初始湖泛面进行识别,划分出2个三级层序(Jsq1和Jsq2),每个三级层序又划分为3个体系域,即低位体系域、湖侵体系域和高位体系域。对准层序、准层序组进行识别,划分19个准层序,分别对应19个小层,对5口单井进行层序划分,在横向上进行连井层序对比。对2个三级层序的地层特征进行研究,在此基础上,研究三工河组层序形成的主要控制因素。研究结果表明:构造活动是层序形成的主要控制因素;沉积物供给条件和气候变化对层序形成有较大的影响,湖平面的变化是构造沉降、气候变化、沉积物供给等因素的综合反映。     

Middle-Late Jurassic marine dinoflagellate cysts from the eastern Qiangtang Basin in the Qinghai-Tibet Plateau, China

Dinoflagellate cysts from two Middle-Late Jurassic sections in the Wenquan and Yanshiping regions of the Qiangtang Basin comprise 24 genera and 36 species including one new taxon of the genus Tenua. Based on their stratigraphic distribution, six assemblage zones are recognized in ascending order as follows: 1) Tubotuberella egemenii Zone, probably Callovian, in the mid-upper part of the Xiali Formation; 2) Pareodinia ceratophora Zone, probably Oxfordian, in the lower part of the Suowa Formation; 3) Batiacasphaera floralis Zone, probably Oxfordian, in the middle part of the Suowa Formation; 4) Amphorula metaelliptica Zone, probably Early Kimmeridgian, in the upper part of the Suowa Formation; 5) Alisocysta spp. Zone, probably Early Kimmeridgian, in the base of the Xueshan Formation; 6) Tenua wenquanensis sp. nov. -Dichadogonyaulax schizoblata Zone, probably Late Kimmeridgian-Tithonian, in the lower part of the Xueshan Formation. Based on our analysis the Jurassic-Cretaceous Boundary in the Wenquan section is placed higher than previously.     

Middle-Late Jurassic marine dinoflagellate cysts from the eastern Qiangtang Basin in the Qinghai-Tibet Plateau, China

Dinoflagellate cysts from two Middle-Late Jurassic sections in the Wenquan and Yanshiping regions of the Qiangtang Basin comprise 24 genera and 36 species including one new taxon of the genus Tenua. Based on their stratigraphic distribution, six assemblage zones are recognized in ascending order as follows: 1) Tubotuberella egemenii Zone, probably Callovian, in the mid-upper part of the Xiali Formation; 2) Pareodinia ceratophora Zone, probably Oxfordian, in the lower part of the Suowa Formation; 3) Batiacasphaera floralis Zone, probably Oxfordian, in the middle part of the Suowa Formation; 4) Amphorula metaelliptica Zone, probably Early Kimmeridgian, in the upper part of the Suowa Formation; 5) Alisocysta spp. Zone, probably Early Kimmeridgian, in the base of the Xueshan Formation; 6) Tenua wenquanensis sp. nov. -Dichadogonyaulax schizoblata Zone, probably Late Kimmeridgian-Tithonian, in the lower part of the Xueshan Formation. Based on our analysis the Jurassic-Cretaceous Boundary in the Wenquan section is placed higher than previously.     

New discovery on dinosaur fossils from Early Jurassic, Sichuan, China

An early and primitive sauropod dinosaur, Gongxianosaurus shibeiensis (gen. et sp. nov.), from Lower Jurassic Dongyuemiao Member of Ziliujing Formation in Shibei Village, Gongxian County, Sichuan Province, China is described, which is among Gongxian dinosaur fossils discovered in 1997. Except for skull incomplete, fossils were well-preserved. It has concurrently some features of both sauropod and prosauropds. It is an intermediate type of evolution from prosauropod to sauropod, provides practical materials for studying of origin and evolution of sauropod dinosaur fauna, and a favourable way for stratigraphic correlation between Early Jurassic Ziliujing Formation and Lower Lufeng Formation, in the Sichuan Basin and the Central Yunnan Basin that lies to its southwest.     

六盘山盆地东部炭山地区下白垩统砾岩层位归属及地层对比新认识

六盘山盆地早白垩世地层称为六盘山群,由下至上划分为三桥组、和尚铺组、李洼峡组、马东山组和乃家河组,其中三桥组由紫红色砾岩组成。位于六盘山盆地东部的固原炭山剖面是六盘山盆地白垩系重点研究剖面,该剖面下白垩统六盘山群下部含有一套厚度为28.0 m的砾岩,以往一直归为三桥组,但本套砾岩的基质或填隙物为灰绿色,与三桥组的砾岩的基质或填隙物为紫红色明显不同,通过结合地震剖面地层解释和沉积演化规律研究,新确定了炭山下白垩统剖面的砾岩层位为李洼峡组边缘相,本剖面缺失六盘山群下部的三桥组、和尚铺组。     

用地震属性分析莫8井区J_1s_2~1砂体微相展布

地震属性分析和砂体微相划分在以往的储层研究中都是分开进行的,彼此间没有很好地结合,从而降低了储层砂体微相研究的精度和准确性.作者在建立的层序地层格架的基础上,以莫8井区为例,对储层各种地震属性参数进行了提取和分析,并利用属性特征进行了J1s21砂体微相的研究和刻画,划分了有利含油气区.     

西准噶尔白碱滩北部太勒古拉组深水沉积研究

论述了西准噶尔札依尔山南缘下石炭统（或包括部分上泥盆统）太勒古拉组中发现的深水火山碎屑岩沉积特征；根据粒序、沉积结构和构造、横向与垂向上的特点，将深水火山碎屑岩划分为６种岩组，并建立了４种岩相组合；剖面垂向层序表明：从底向上，粒序由粗变细，层厚由厚变薄，“近基”火山碎屑浊积岩逐渐被“远基”浊积岩代替，表明研究区泥盆纪末至早石炭世，洋盆扩张，火山喷发由强变弱，沉积环境由深海浊积中扇向外扇演化     

Stratigraphy and paleontology of the marine Jurrassic strata in Vietnam

Marine Jurassic strata in Vietnam have yielded characteristic ammonites and occur in: (1) west Quang Binh Province located in the eastern margin of the Nam Theun Basin (the main part of which is located in Middle Laos); (2) the Nong Son Basin situated in the north of the Kon Tum Geoblock; (3) the Da Lat Basin, the largest Jurassic basin in Vietnam, extending from the southern margin of the Kon Tum Geoblock to southeast of Ho Chi Minh City. In the first two, Lower Jurassic marine beds occupy the lower part of the section and grade up into Middle Jurassic red beds. In central Da Lat Basin the section consists completely of marine strata containing many ammonite levels dated from Early Sinemurian to Bajocian, whereas the marginal basin section is like the first two areas. Based particularly on biostratigraphical evidence, a marine transgression is considered to have entered the Indochina Block as early as the Late Hettangian. During the early transgression the fauna was distinctly endemic, showing the separate character of the basins, but since the Late Sinemurian, communication between the Da Lat and other basins was established; the marine regime in Da Lat Basin ended around the Late Bathonian.     

Stratigraphy and paleontology of the marine Jurrassic strata in Vietnam

Marine Jurassic strata in Vietnam have yielded characteristic ammonites and occur in: (1) west Quang Binh Province located in the eastern margin of the Nam Theun Basin (the main part of which is located in Middle Laos); (2) the Nong Son Basin situated in the north of the Kon Tum Geoblock; (3) the Da Lat Basin, the largest Jurassic basin in Vietnam, extending from the southern margin of the Kon Tum Geoblock to southeast of Ho Chi Minh City. In the first two, Lower Jurassic marine beds occupy the lower part of the section and grade up into Middle Jurassic red beds. In central Da Lat Basin the section consists completely of marine strata containing many ammonite levels dated from Early Sinemurian to Bajocian, whereas the marginal basin section is like the first two areas. Based particularly on biostratigraphical evidence, a marine transgression is considered to have entered the Indochina Block as early as the Late Hettangian. During the early transgression the fauna was distinctly endemic, showing the separate character of the basins, but since the Late Sinemurian, communication between the Da Lat and other basins was established; the marine regime in Da Lat Basin ended around the Late Bathonian.     

元素录井分析在复杂构造带超深钻井地层识别的应用——以准噶尔南缘中段上侏罗统-下白垩统为例

准噶尔盆地南缘中段下组合地层总体埋藏深度为6 000～7 000 m,构造条件复杂,常规地层岩性识别依靠人为判定,缺乏定量判定标准。元素录井对岩屑样品的元素含量进行检测,为岩性和地层定量识别提供了数据基础。以准噶尔盆地南缘中段为例,在上侏罗统的喀拉扎组和下白垩统的清水河组超深地层中获取627个岩屑样品,利用手持式X射线荧光光谱仪对岩屑元素含量进行检测。通过元素箱型图和图谱分析建立元素的含量与岩性对应关系,对敏感性元素的含量进行交会分析,建立不同岩性元素定量标准,探讨标志层的元素定量特征。结果表明,样品的SiO₂和Fe含量与岩性相关性强,其中Fe含量与泥质含量呈正相关性;SiO₂含量与砂质含量呈正相关性。SiO₂含量与Fe含量之比大于24.53为砂岩,两者含量之比小于等于24.53为泥岩。岩屑的Ca元素含量突增是清水河组和喀拉扎组分界标志。元素录井分析实现了准噶尔南缘中段上侏罗统-下白垩统复杂构造带超深钻井地层岩性和地层定量判别,为山前复杂构造带的构造解释提供新依据。     

准噶尔盆地滴南地区原油地球化学特征及油源

对准噶尔盆地东道海子凹陷滴南地区的滴南1、滴南7、滴南8等井原油与烃源岩地球化学特征分析,探论该区油源关系。通过对原油的族组成、碳同位素、饱和烃色谱、甾萜烷化合物及轻烃参数、烃源岩的生物标志化合物的研究,结果表明：东道海子凹陷二叠系平地泉组烃源岩处于低成熟－成熟阶段,三环萜烷含量高,Ts＜Tm,γ蜡烷含量低,甾烷中 C27、C28、C29呈反“L”形分布。滴南地区二叠系原油和储层抽提物地球化学参数及甾萜烷特征与平地泉组烃源岩相似,具有亲缘关系。侏罗系原油具有侏罗系烃源岩来源的特征。     

储层临界物性对岩性圈闭油气成藏的意义——以准噶尔盆地东部白家海凸起侏罗系储层为例

准噶尔盆地东部白家海凸起侏罗系岩性油气藏发育,同一个区带上不同岩性圈闭的成藏机理存在差异性.针对岩性圈闭多元控油、主元成藏的特征,从岩性圈闭成藏主控因素中的储层临界物性出发,采用孔渗交会法和含油产状法,结合试验分析,对白家海凸起彩43井区侏罗系西山窑组的地层条件含油临界孔隙度进行研究.同时尝试从地层条件下的含油临界孔隙度、含油临界渗透率及含油孔喉特征等方面,对西山窑组现今及白垩纪末期的储集层含油性进行分析,发现常规实验室条件下侏罗系储集层的含油临界渗透率为0.1×10-3μm2,临界孔隙度值约为11.5%.垂向上储集层的含油临界孔、渗物性随埋深变化.采用有效含油孔隙度、有效含油渗透率和优势流动系数3个储集层临界物性参数进行分析,发现储层临界物性对白家海凸起侏罗系油气藏形成具有明显的控制作用.     

准噶尔盆地彩参2井侏罗纪孢粉化石及层序地层分析

对准噶尔盆地彩参 2井侏罗纪孢粉化石研究表明 ,八道湾组具有deltoidospora cycadopites protoconiferus classopollis组合 ,三工河组具有cyathidites osmundacites pinuspollenites classopollis组合 ,西山窑组为cyathidites dic tyophyllidites cycadopites perinopollenites组合 ,石树沟群为cyathidites klukisporites classopollis concentrisporites组合 ,它们对地层时代有较好的指示意义。对孢粉古生态和沉积岩颜色、岩性及粘土矿物成分综合研究表明 ,研究区八道湾为暖温带潮湿气候 ;三工河早期为亚热带干旱、半干旱气候 ;三工河中晚期至西山窑期为亚热带潮湿气候 ;石树沟群早期为亚热带半干旱气候 ,但发生过两次时潮时旱的气候波动 ,石树沟群晚期气候干旱炎热 ,并促使湖盆急剧收缩、消亡。侏罗系可划分为 6个层序 ,层序界面附近的孢粉丰度及分异度最小 ,而最大湖侵期的孢粉丰度及分异度最大     

鄂尔多斯盆地陕北斜坡带三叠系延长组和侏罗系油气成藏期研究

通过对鄂尔多斯盆地烃源岩的生烃史、构造运动特征、包裹体均一温度和伊利石K-Ar同位素定年的研究,结合研究区的裂缝发育特征,综合分析了三叠系延长组和侏罗系油气成藏期.鄂尔多斯盆地形成演化过程中经历了多期构造运动,其中影响最大的是早白垩世末期的构造运动.长7段泥质烃源岩在早白垩世初期开始大量生烃,对侏罗系延9段裂缝储层和三叠系延长组伊利石K-Ar同位素定年以及对储层流体包裹体均一温度分析显示,陕北斜坡带三叠系延长组油藏形成于早白垩世的早中期,而侏罗系延安组的油藏则形成于早白垩世末的构造抬升期,对应时间为晚白垩世早—中期.     

准噶尔盆地侏罗系层序格架中油气藏的分布规律及其主控因素

以 17条统一流程处理的区域地震大剖面为骨架网 ,综合分析地震、钻井和露头资料的结合 ,并经过 6次反复标定 ,建立起准噶尔盆地侏罗系统一的层序地层格架。将 5 8个已发现的侏罗系油气藏归位到层序和体系域中 ,分析其在层序和体系域中的分布规律。研究发现 ,在层序级别上 ,不同地区油气富集的层位不同 ,总体上有从西到东层位变新的趋势 ;在体系域级别上 ,侏罗系油气主要富集在低位域 ,只在腹部有少量的油气藏位于水进域和高位域。层序格架对油气富集的控制作用主要表现为储盖组合条件对油气聚集的控制 ,不同体系域内储集层物性的差异对油气富集也有控制作用。因此 ,在今后对准噶尔盆地侏罗系的油气勘探中 ,应重视低位域和盆地的边缘地带。