Origin and significance of the Toolebuc gamma‐ray anomaly in parts of the Eromanga Basin

The Toolebuc Formation, which is a potentially important source of oil shale in the Eromanga Basin of NW Qld, exhibits a marked gamma‐ray response that has long beeen used as a stratigraphic marker. At Julia Creek, a large area of the Formation contains low‐grade oil shale that is accessible to mining. Detailed investigation, by gamma‐ray spectrometry and neutron activation analysis, of drill core samples from this deposit and from the type section of the Toolebuc Formation at Boulia (BMR Boulia 3A stratigraphic drill hole) show that the Toolebuc gamma‐ray anomaly in the northern Eromanga Basin is due to the presence of uranium. Analyses for organic carbon and phosphorus show that the uranium is associated primarily with organic matter in the oil shales and with phosphatic skeletal fish debris in the accompanying coquinites.

Drill core samples from Tibooburra, N.S.W. were also analysed (BMR Urisino‐1 stratigraphic drill hole) to investigate whether the gamma‐ray anomalies observed in the Bulloo Embayment on the southern margin of the Eromanga Basin (possibly correlative with the Toolebuc Formation) might also be indicative of oil shale. The results show that the much weaker anomaly at this locality is due principally to potassium and reflects the presence of an argillaceous siltstone within glauconitic sandstones.     

再论鄂尔多斯盆地延长组长73砂层组与烃源岩相关的高伽马砂岩

针对自然伽马等常规测井系列长期仅能将鄂尔多斯盆地延长组长7₃砂层组大规模发育的与烃源岩相关的高伽马砂岩解释为“油页岩等优质烃源岩”的问题,根据岩心观察及测录井资料、电子探针薄片和大量页岩油实际生产资料的分析,对长7₃砂层组内与烃源岩相关的高伽马砂岩的定义、成因以及其发育特征与长7油层组页岩油试油效果的关系进行了探索性的研究。研究表明,鄂尔多斯盆地长7₃砂层组内与烃源岩相关的高伽马砂岩可划分为狭义和广义两种类型,高放射性的成因可能与深部热水作用有关,首次发现其发育特征与长7油层组页岩油试油效果关系密切。该项研究对鄂尔多斯盆地延长组长7油层组页岩油的大规模高效勘探与开发具有重要的理论和现实意义。     

利用测井技术评价松辽盆地南部油页岩

为了利用松辽盆地南部已有钻井的测井资料评价油页岩,分析了松辽盆地南部嫩二段油页岩的测井响应特征,充分利用测井资料连续性的优势,采用5口井93块油页岩岩心的有机碳、含油率化验分析数据和测井响应特征,建立嫩二段油页岩的有机碳含量与含油率之间定量关系式T^a=0.548 6TOC+0.18和△logR、自然伽玛与有机碳含量之间的定量关系式TOC=6.262 8×△logR+1.05,进而建立利用测井资料定量评价油页岩含油率模型T^a=0.546 8a×△logR＋0.548 6×△TOC＋0.18。通过模型计算出的油页岩段的含油率与油页岩实测含油率数据基本一致,而且计算出的含油率值连续。     

松辽盆地农安地区上白垩统油页岩含油率影响因素

农安油页岩含矿区地处松辽盆地东南隆起区,主要发育于上白垩统青山口组一段、嫩江组一、二段。油页岩有机质的干酪根类型为Ⅰ-Ⅱ₁型,质量较好,处于成岩的未成熟阶段。油页岩含油率与有机碳和氢元素含量间存在明显的线性正相关关系,当有机碳质量分数＞6％或氢质量分数＞1％时构成油页岩。此外,有机质干酪根的显微组分可以反映有机质的类型,与含油率之间也存在一定的相关性。青山口-嫩江组沉积时期,该区温暖湿润的古气候条件、大规模的海侵和缺氧事件影响了油页岩中有机质的丰度和类型,从而影响了油页岩的含油率。     

Relation between source rock properties and wireline log parameters: An example from Lower Jurassic Posidonia Shale, NW-Germany

The relationships between source rock quality and wireline log parameters were established for the Lower Jurassic Posidonia Shale, the most prolific petroleum source rock of Central Europe. Wireline logs used are the gamma ray spectrometry, density, sonic and various resistivity logs. The organic geochemical parameters considered include the organic carbon content, hydrogen index, and the hydrocarbon potential expressed by pyrolysis yield. The case history presented is based on a continuous core through the entire Posidonia Shale interval from a location where this source rock is immature. Care was taken to detect and to avoid samples and log values influenced by bore hole roughness and fractures. Fair correlations were observed only between uranium content from gamma ray spectrometry log and organic carbon content. No correlation was recognized between uranium content and kerogen type as defined by hydrogen indices. For various reasons density, sonic, and resistivity logs did not provide useful data in this study.Three rock units with irregular, high and low uranium contents could be differentiated. Possible causes for this tripartition are different environments during deposition and postdepositional redistribution of uranium during early diagenesis and in association with fractures.     

西藏伦坡拉盆地丁青湖组油页岩特征及勘探有利区评价

西藏伦坡拉盆地出露大规模的油页岩。通过研究油页岩的剖面、探槽、钻井及相关实验数据,根据油页岩厚度、分布范围及沉积相特征,结合油页岩品质特征,对蒋日阿错、伦坡日及爬爬3个油页岩分布区进行了评价。研究表明,伦坡拉油页岩总体为高灰分(平均81.76%)、中高含油率(平均7.2%)、特低含硫量(小于1%)型油页岩,其有机碳含量高(平均8.07%),产烃潜量较大,可作为烃源岩为伦坡拉盆地的油藏提供油源。油页岩厚度受沉积相带控制,主要呈北西-南东向断续分布于盆地半深湖-深湖相区。油页岩平均含油率、有机碳含量总体呈北西部低、南东部较高的趋势。综合油页岩厚度及油页岩展布范围,爬爬地区油页岩具有厚度较大、东西向展布最广、平均含油率及有机碳含量高的特征,是最有利的油页岩勘探区,伦坡日、蒋日阿错地区则次之。     

Geology of the Devonian black shales of the Appalachian Basin

Black shales of Devonian age in the Appalachian Basin are a unique rock sequence. The high content of organic matter, which imparts the characteristic lithology, has for years attracted considerable interest in the shales as a possible source of energy. The recent energy shortage prompted the U.S. Department of Energy through the Eastern Gas Shales Project of the Morgantown Energy Technology Center to underwrite a research program to determine the geologic, geochemical, and structural characteristics of the Devonian black shales in order to enhance the recovery of gas from the shales. Geologic studies by Federal and State agencies and academic institutions produced a regional stratigraphic network that correlates the 15 ft black shale sequence in Tennessee with 3000 ft of interbedded black and gray shales in central New York. These studies correlate the classic Devonian black shale sequence in New York with the Ohio Shale of Ohio and Kentucky and the Chattanooga Shale of Tennessee and southwestern Virginia. Biostratigraphic and lithostratigraphic markers in conjunction with gamma-ray logs facilitated long-range correlations within the Appalachian Basin. Basinwide correlations, including the subsurface rocks, provided a basis for determining the areal distribution and thickness of the important black shale units. The organic carbon content of the dark shales generally increases from east to west across the basin and is sufficient to qualify as a hydrocarbon source rock. Significant structural features that involve the black shale and their hydrocarbon potential are the Rome trough, Kentucky River and Irvine-Paint Creek fault zone, and regional decollements and ramp zones.     

松辽盆地东南隆起超大型油页岩矿床特征及成因

研究区内已发现的超大型油页岩矿床位于吉黑地槽褶皱系松辽中断陷的一个三级构造单元--松辽盆地东南隆起内。研究区主要发育白垩纪地层,属于陆源碎屑岩沉积。经钻井岩心观察和采用“费舍尔”方法对含油率测试分析表明,油页岩层主要赋存在早白垩世青山口组和晚白垩世嫩江组。含油页岩层系整体为一套厚层的暗色泥页岩和油页岩组合。井间油页岩层对比和油页岩平面展布特征显示,该区油页岩呈层状、规模大、分布范围广、矿层稳定、连续性好。研究证实矿石含油率与有机质组分及总有机碳关系密切,矿石灰分大,属低品质油页岩矿石。通过对油页岩特征及成矿环境分析,认为矿床成因属于腐泥型页岩-油页岩。     

川东焦石坝地区页岩气特征及其意义

焦石坝地区五峰组-龙马溪组页岩富集有大量的天然气,但针对页岩气地球化学特征研究还较薄弱,其蕴含的地质意义不甚明确.通过页岩气组分及其碳同位素特征和页岩干酪根的碳同位素特征分析,讨论了页岩气的来源、成因类型和完全倒转的碳同位素分布特征.五峰组-龙马溪组页岩具有很好的生烃能力、有机质丰度与含气量的关系有明显的正相关性、甲烷与干酪根相似的碳同位素特征、地层的超压特征等,综合表明研究区天然气应为页岩自生自储的页岩气;页岩气的甲烷含量均超过98%,其碳同位素平均为-29.93‰,反映了成熟度已经达到过成熟干气阶段;相对稳定的ln（C₁/C₂）和快速增大的ln（C₂/C₃）揭示其成因主要为二次裂解气;页岩气碳同位素完全倒转的分布特征主要受到在相对封闭环境中的原油裂解生气作用的影响,其完全倒转的碳同位素分布特征也反映了研究区良好的页岩气保存、富集条件.      

吉林松江盆地大拉子组上段油页岩特征及成矿机制

吉林省延边地区早白垩世大拉子组上段地层以含油页岩为特征。松江盆地大拉子组上段油页岩呈灰褐色或灰黑色,表现为纸片状和致密块状。有机质类型为腐泥型-腐殖腐泥型,含油率为3.8%～6.2%。大拉子组上段发育7个含油页岩层位,2号层和7号层为具有工业开采价值的矿层,产状不稳定,自东向西、由南向北累计厚度增大。致密块状油页岩发育于松江向斜轴部杨木屯地区、向斜北翼的老偏坡—东山一线,纸片状油页岩见于向斜南翼的杨木屯—松江镇北以及胜利屯一带。大拉子组上段地层可划分为两个三级层序,2号和7号油页岩矿层皆为半深湖-深湖成因,分别形成于层序I、层序II的高位体系域时期。湖水分层稳定、藻类勃发、半深湖-深湖长期滞水缺氧的还原环境、有机质有效聚集保存有利于油页岩成矿,频繁发育的重力流湖泊水下扇沉积则不利于成矿。     

湘中涟源凹陷上泥盆统佘田桥组页岩地球化学特征及有机质富集机理

上泥盆统佘田桥组是湘中地区页岩气勘探的重要层系之一.为了探讨湘中地区涟源凹陷上泥盆统佘田桥组黑色泥页岩有机质富集机理,系统采集了区内湘新地3井佘田桥组20个泥页岩岩心样品,开展有机碳含量、主量元素、微量元素以及稀土元素等地球化学特征测试,分析佘田桥组页岩的古盐度、古气候、古氧化还原条件和古生产力等古沉积环境.结果表明:佘田桥组底部层段有机碳含量较高（1.28%~2.68%）,平均值为1.69%.页岩主要成分为SiO₂（50.27%）、Al₂O₃（13.66%）、CaO（11.55%）.微量元素Rb、Sr和Zr富集而Co、Mo、Sc和Hf亏损.Sr/Ba、化学蚀变指数（CIA）、Th/U、V/Sc、V/Cr、δU比值表明佘田桥组富有机质页岩段沉积环境为淡水-半咸水、干旱的贫氧-次富氧环境,贫有机质页岩段为咸水、干旱-半干旱的富氧环境.结合区域层序地层特征,综合对比佘田桥组有机碳含量（TOC）与古氧化还原条件、古生产力条件的相关性,揭示出涟源凹陷佘田桥组富有机质页岩段有机质富集的主控因素为古氧化还原环境,而贫有机质页岩段有机质主要来源于陆源供给.      

柴北缘团鱼山地区中侏罗统石门沟组油页岩有机地球化学特征及古湖泊条件

根据Leco（莱科）、岩石热解、GC（气相色谱）和GC-MS（气相色谱/质谱）等分析,开展了柴达木盆地北缘团鱼山地区中侏罗统石门沟组油页岩有机地球化学特征研究,探讨了油页岩的生烃潜力、有机母质来源、沉积环境及成矿差异。结果表明：石门沟组页岩段共发育3层油页岩（自下而上分别为油1、油2和油3）,油页岩w（TOC）较高,平均值为8.16%,有机质类型为Ⅰ型和Ⅱ₁型,整体生烃潜力较好,且油1、油2的生烃潜力高于油3;样品中检测出丰富的正构烷烃、类异戊二烯烷烃、甾类化合物、萜类化合物和芳香烃化合物,其中,正构烷烃呈单峰式分布,主峰碳数为nC₂₃或nC₂₇,Pr/Ph值为0.20~1.08,油1、油2的C₂₇/C₂₉值、芳基类异戊二烯烃、藿烷和藿烯质量分数明显比油3高,揭示油1、油2形成于强还原条件,有机母质来源以低等水生生物为主,油3形成于弱还原-还原条件,有机母质来源具有陆源高等植物与低等水生生物双重生源特征。结合油页岩特征的差异及古湖泊条件,说明较深的湖水并不是形成优质油页岩的必要条件,藻类、细菌等提供优质有机质的生物输入以及底层水的强还原条件更有利于优质油页岩的形成。     

页岩沉积环境对其油气潜力的影响:以中国和北美对比研究为例

页岩油气是当前全球油气勘探和研究的热点,但其潜力评价一直是难点。该文以中国和北美的四套典型页岩为例,包括北美湖相Green River组、内陆海相Niobrara组、中国环境来评价相龙马溪组和济阳坳陷湖相页岩,发现页岩沉积环境与其油气潜力具有密切关系,因此可通过分析发现这四套页岩的沉积环境都具有页岩沉积环境评价其页岩油气潜力。通过微量元素、生物标志化合物、扫描电镜、X-CT和X射线衍射等方法,发现这四套页岩都具有一定的还原性和较高的生产力,且具有差异性。内陆海相Niobrara组页岩具有弱还原的沉积环境,在四套页岩中有机碳含量较低,呈块状沉积构造,裂缝与微裂缝较少,储集空间相对有限。焦石坝海相龙马溪组页岩为还原的沉积环境,岩石以富含有机质的硅质岩为主,可观察到大量的大孔隙与少量的微裂缝。Green River页岩和济阳坳陷页岩形成于陆相咸化的强还原沉积环境,有机碳含量高,页岩以纹层状结构为主,岩石组成脆性矿物含量高,含有大量的裂缝。可见,具有强还原沉积环境的页岩通常具有较好的勘探前景。     

黑龙江省依兰盆地古近系达连河组油页岩沉积特征

达连河油页岩含矿区位于黑龙江省依兰地区,该区是一个半地堑式断陷盆地。古近系达连河组为一个完整的三级层序,油页岩形成于水进体系域和高水位体系域发育时期。油页岩沉积相类型为半深湖相沉积,与泥炭沼泽相煤层伴生,为煤层的顶板,含油率为3.75%~8.37%,有较高的开采价值。煤层顶部发育的巨厚湖相劣质油页岩,分布广,层位稳定,含油率<3.5%。研究区油页岩成因类型为混合型和腐殖型。根据油页岩工业划分标准,达连河油页岩属于中灰分、低含油率的油页岩。     

中国陆相油页岩含油率与总有机碳的响应机理

为了建立稳定可靠的利用油页岩总有机碳预测含油率的模型,揭示中国陆相不同成因类型油页岩含油率与总有机碳的内在关系极其重要。通过不同类型盆地油页岩钻井取心测试的关键参数,结合沉积学、有机地球化学、热模拟等学科技术,探讨油页岩含油率与总有机碳的响应机理。结果表明：不同盆地类型与沉积背景下发育的油页岩含油率与总有机碳质量分数均呈现良好的正相关性（R²=0.81~0.97）;中国陆相油页岩的成因类型进一步划分为5种类型,制约着含油率与总有机碳的内在关系;油页岩的升温加热模拟呈现3个失重阶段（温度<150、300~550、600~750℃）,明确了含油率与总有机碳参数的物理意义;相同类型盆地与沉积背景下形成的油页岩具有相近的母质生源组合,从而具有大致相当的再生烃效率。中国陆相油页岩成因类型的细划、含油率与总有机碳物理意义的明确、油页岩再生烃能力的分析,有助于理解中国陆相油页岩含油率与总有机碳的内在响应关系。     

金衢盆地上白垩统金华组湖相页岩油气地质特征

以金衢盆地白垩系金华组为研究对象,在钻井资料分析的基础上,结合区域沉积背景,通过分析暗色泥页岩有机质丰度、厚度和分布范围,研究和探索了金衢盆地上白垩统金华组湖相页岩油气地质特征。金衢盆地金华组湖相暗色泥页岩样品的有机质丰度特征表明,TOC值一般小于0.5%,属于非烃源岩,个别样品达到1.57%,属于优质烃源岩; 富有机质层段以富砂夹泥型或富泥夹砂型为主,具多产层特征,盆地北部凹陷具备一定的页岩油气勘探潜力。金华组湖相暗色泥页岩主要发育在西北部衢州—龙游沉积中心区,区域较为局限,厚度不均,范围5~100 m,平均孔隙度3.867%,平均最大渗透率0.087 2×10^-3 μm²,属于典型的致密型储层。将富有机质层段砂泥地层作为一个整体进行页岩油气勘探,源储一体是今后陆相页岩油气的重要勘探思路。     

The REE Characteristics of Oil Shales in the Lower Eocene Celtek Formation (Yozgat,Turkey) and their Relation to Tectonic Provenance

The Lower Eocene Celtek Formation is located in the Sorgun district of thecity of Yozgat in Turkey.In the study area,Paleozoic,Campanian-Maastrichtian,Eocene,Miocene and Quaternary units are exposed.The Celtek Formation is noteworthy with its coal and oil shale deposits.Samples were collected from one exposure(YCOSK)and two boreholes(SJ and C boreholes)at the facility operated by the Yeni Celtek Coal Management.Concentrations of REE in oil shales from these localities were determined using the ICP-MS technique.REE and total organic carbon(TOC)values of a total of 32 samples were compared with normalized REE contents of various environments.TOC contents of the samples ranged from 1.37wt%to 11.8wt%(mean 4.96wt%).The averages of all samples for the all normalized values show similar patterns.Normalized REE patterns are represented by the enrichment in the order of LREE>MREE>HREE and display negative Ce and positive Eu anomalies.ΣREE vs.TOC were compared.ΣREE vs.TOC showed a weak positive correlation,whereasΣLREE vs.(M+HREE)andΣLREE vs.ΣREE were positively correlated.Regarding tectonic provenance characteristics,the Celtek Formation oil shales were formed in microenvironments with physicochemical conditions changing in character from oxic to euxinic,representing a transitional terrestrial–marine environment.     

鄂西地区陡山沱组页岩储层孔隙特征及影响因素

页岩储层孔隙结构是评价页岩气资源潜力的基础。本文基于有机碳含量、沥青反射率、X射线衍射、场发射扫描电镜(FE-SEM)及低温氮气吸附等方法,探讨鄂西地区震旦系陡山沱组页岩沉积组成、孔隙结构及其控制因素。结果表明:(1)陡山沱组为硅质和钙质页岩,TOC介于3.29%～6%,主要为I型干酪根,处于高-过成熟阶段;(2)陡山沱组页岩有机孔发育程度较低,无机孔提供主要储集空间,包括脆性矿物和黏土矿物的粒间孔、层间孔和部分溶蚀孔,以及少量微裂缝;(3)孔径分布范围为1.1～284nm,总孔体积平均为0.034ml/g,微孔、介孔和大孔体积分别为0.005ml/g、0.023ml/g和0.006ml/g,以介孔为主;(4)陡山沱组页岩TOC与孔体积无明显相关性,表明有机孔对孔体积贡献较小。硅质矿物和黏土矿物含量与页岩孔体积正相关性较好,表明矿物组成是陡山陀组页岩孔隙发育的主要控制因素。鄂西地区陡山沱组页岩具有良好的物质条件、生烃条件和页岩气储集空间,是潜在的页岩气勘探开发层系。     

湘中涟源凹陷上二叠统龙潭组和大隆组海陆过渡相泥页岩孔隙结构特征及对比

以湘中坳陷涟源凹陷上二叠统龙潭组和大隆组海陆过渡相泥页岩为研究对象,重点选取12块典型泥页岩钻井岩心样品开展有机碳含量、岩石热解、X射线衍射、密度法孔隙度、高压压汞、二氧化碳和氮气吸附等测试分析,利用氩离子抛光-场发射扫描电镜（FE-SEM）观察了泥页岩孔隙特征,通过定性描述和定量测定相结合的方法研究了海陆过渡相泥页岩纳-微米级孔隙结构特征及孔隙发育影响因素.研究结果表明:龙潭组和大隆组泥页岩有机碳含量均较高,热演化程度处在凝析油和湿气生成阶段早期,对应R_o为1.22%~1.43%;泥页岩孔隙类型主要为粒间孔、粒内孔、有机孔和微纳米缝.龙潭组与大隆组样品在孔隙形态、孔隙大小和影响因素上均有差异:龙潭组样品氮气吸附滞回环开口宽,有机孔形态多为圆形和椭圆形,孔径较大;大隆组样品氮气吸附滞回环开口窄,有机孔形态多为不规则状,孔径较小;龙潭组泥岩和大隆组泥页岩样品有机碳含量与黏土矿物含量呈正相关关系,2套样品的微孔孔隙积体与有机碳和黏土矿物含量均呈正相关性;龙潭组样品介孔+宏孔的孔隙体积与有机碳和黏土矿物含量呈正相关性,与石英+长石含量呈负相关性;大隆组样品中的碳酸盐矿物对其孔隙性有明显影响,大隆组样品介孔+宏孔孔隙体积与有机碳、黏土矿物和石英+长石含量相关性不明显.      

辽西金羊盆地下侏罗统北票组页岩气地球化学特征及其成因

金岭寺-羊山盆地(金羊盆地)是中国北方侏罗系发育最完备的地区之一,盆地内充填的下侏罗统北票组为一套湖相泥岩,具有良好的油气潜力。在金羊盆地章吉营子凹陷西缘布置实施的4口地质调查井中,有3口井见油气显示。通过对SZK2及SZK3钻井岩心进行现场解析,北票组泥页岩在浅层测试到可观的页岩气含量,且随着深度的变化,总含气量及甲烷含量有所增加。另外,其总含气量与有机碳含量呈良好的正相关关系,是影响页岩含气量的关键因素。对比金羊盆地北票组泥页岩吸附气C同位素特征,其气体成因主要存在生物成因气和煤型气2种类型,表明下侏罗统北票组页岩气具有混合多成因的特征。通过X衍射分析综合评价,金羊盆地下侏罗统北票组泥页岩压裂条件好、天然气吸附能力强,具备一定的页岩气勘探前景,是有利的页岩气勘探开发新层系。