利用气体吸附法和压汞法研究烃源岩孔隙分布特征——以松辽盆地白垩系青山口组一段为例

烃源岩中微观孔隙空间是油气初次运移的重要通道,同时也是残留烃主要的储集空间.本文对烃源岩中不同尺度的孔隙分别使用气体吸附法和压汞法进行测定,进而对孔隙分布进行系统分析.实验结果表明,青山口组一段烃源岩孔隙度较低,分布于1.2％～3.87％之间,平均为2.17％,主要以微孔和介孔为主,孔容分布于1.8～ 30 mL/mg之间,平均为9.49 mL/mg;比表面积分布于0.91 ～31.02m2/g之间,平均为7.02 m2/g.同时本文探讨了不同岩石组成对烃源岩内孔隙发育与分布的影响,发现有机质、伊利石及黄铁矿含量与孔容之间具有较好的正相关关系,孔隙的大小及数量随其含量的增高而增加,而粘土矿物中的绿泥石以及非粘土矿物中石英、方解石、斜长石含量与孔容之间呈负相关关系,烃源岩中的孔隙可能会随其含量的增高而减少,高岭石含量与孔容之间相关性较差,表明烃源岩孔隙可能不受其影响.此外,烃源岩中孔隙发育及分布还受有机质类型、丰度、热演化程度、粘土矿物排列形式、非粘土矿物的次生变化等因素的影响.     

渤海莱州湾凹陷不同类型烃源岩活化能影响因素分析

选取不同干酪根类型的低熟烃源岩作为剖析对象,从干酪根类型、干酪根中有机硫含量、可溶有机质和黏土矿物对烃源岩活化能的影响进行研究,结果表明:Ⅱ₁和Ⅰ干酪根活化能分布范围窄,Ⅱ₂和Ⅲ干酪根活化能分布范围宽,干酪根平均活化能Ⅲ>Ⅱ₂>Ⅰ>Ⅱ₁;有机硫含量高的干酪根平均活化能低,有机硫对烃源岩生烃起催化作用;可溶有机质的存在影响烃源岩平均活化能的大小和分布特征,可溶有机质分布在活化能低值区间,对烃源岩生烃起催化作用;烃源岩黏土矿物中伊/蒙混层含量高,平均活化能高;伊利石含量高,平均活化能低,伊利石对烃源岩生烃起催化作用。      

黔南下石炭统打屋坝组页岩气储层物性特征及控制因素

黔南下石炭统打屋坝组页岩气储层孔隙主要包括残余原生粒间孔、晶间孔、有机质孔、粘土矿物间微孔、溶蚀孔和裂缝等类型。以细孔喉、分选差,细歪度的微孔微喉型孔隙结构为特征,具有比表面积大、孔容中等,孔隙度低而渗透率低的特点。打屋坝组泥（页）岩总有机碳含量为082%316%,有机质镜质体反射率为213% 327%,粘土矿物含量平均434%。有机质丰度、粘土矿物含量、成岩演化和构造作用是控制打屋坝组页岩气储层的主要因素。     

黔南坳陷下寒武统烃源岩地球化学特征及成因

为明确黔南坳陷下寒武统烃源岩地球化学特征及成因,采用岩石热解、GC、GC-MS等方法对3个典型剖面样品进行了系统分析。结果表明:黔南坳陷下寒武统黑色岩系为一套区域性海相优质烃源岩,厚约50~150 m;烃源岩TOC值为0.13%～15.40%,平均3.31%(n=169);烃源岩干酪根δ13C值为-35.79‰～-29.88‰,平均-32.85‰(n=35),显微组分主要为腐泥组;烃源岩干酪根海相镜质体反射率值为1.95%～3.96%,其等效镜质体反射率值为2.02%～3.47%;烃源岩饱和烃正构烷烃分布多为单峰形,主峰碳多为C22,C30藿烷和C27规则甾烷含量高,规则甾烷多为C27>C29>C28,Pr/Ph值为0.27～0.62,具较高的伽马蜡烷和硫芴含量,OEP值为0.82~1.11,C31升藿烷22S/(22S+22R)值为0.56~0.63,平均0.59;烃源岩总体具有富集轻稀土元素,Ba、Mo、V、U等元素含量高,具较强Ce负异常、Eu正异常和较高U/Th值等特征。总之,黔南坳陷下寒武统海相烃源岩分布广,厚度较大,有机质丰度高,类型好,热演化程度高,是高古生产力和缺氧环境共同作用的产物,可为黔南坳陷油气生成提供雄厚的成烃物质。     

粘土矿物对有机质生烃的催化作用

烃源岩的有机质主要以有机粘土复合体的形式存在。有机质生烃是一种有机粘土化学反应。反应过程中,有机质与粘土之间存在质子和电子迁移,粘土通过对水分子的吸附和离解为有机质加氢裂解提供H+,而有机质生成的有机酸激活了粘土的催化活性,也为蒙皂石伊利石化反应创造了条件。烃源岩不同粘土矿物的选择性催化特征是影响油气组成的最重要因素。粘土的催化活性大小和发育时间是决定烃源岩生烃潜力大小的因素。由于烃源岩在蒙皂石伊利石化阶段具有最大的催化活性,而且与有机质生烃反应同步,因此富含伊$蒙混合层的烃源岩是世界含油气盆地的最有利烃源岩。不同地质时期的烃类地质储量与烃源岩膨胀性粘土的丰度有密切关系。     

鄂尔多斯盆地泾川地区三叠系延长组烃源岩特征及其沉积环境

泾川地区位于鄂尔多斯盆地西南缘,烃源岩发育情况尚不明确。通过野外地质调查和钻井岩心观察,结合烃源岩测试及元素地球化学资料,对长10—长7烃源岩进行评价,在环境分析的基础上研究影响烃源岩发育的主要因素。结果表明：研究区延长组烃源岩以长7₃泥页岩为最好,有机质类型以Ⅰ型和Ⅱ₁为主,TOC为 0.42%～29%;长10—长7泥岩有机质以Ⅱ₂型为主,平均TOC含量低于 2%;Ro为 0.47%～1.08%,有机质基本已成熟。长10—长7烃源岩形成于温暖潮湿的环境,弱还原弱氧化的淡水介质条件,水深相对较浅。古生产力、沉积速率及水介质环境影响烃源岩发育。热水活动促进了古生物的繁盛,P、Cu含量及 P/Ti值越高,有机质 TOC含量越高。（La/Yb）_N值越高,沉积速率越低,有机质越富集。Cu/Zn值越高,V/Cr值越高,Th/U值越低,水体还原性越好,有机质丰度越高。总之,热水活动提高了古生产力水平,相对较低的沉积速率有利于有机质的富集,还原性较强的水介质条件可使有机质得到良好的保存。陇县一带烃源岩因受陆源植物输入的影响,且形成环境不利,烃源岩品质相对较差。     

自生粘土矿物对文昌A凹陷深部储层的制约

目前关于自生粘土矿物对深层孔隙结构及油气运聚的影响方面的研究十分薄弱.综合利用铸体薄片、全岩XRD、扫描电镜、恒速压汞等测试手段,分析自生粘土矿物对孔隙连通性、孔喉直径及其分布的影响,并结合埋藏史和生烃史探讨了低渗透砂岩不同孔隙结构类型的油气差异富集条件.珠海组深部储层压实作用较强,自生粘土矿物含量较高.碎屑颗粒以线接触-凹凸接触为主,识别出"孔隙+粗喉道"和"喉道主控"2种孔隙结构类型,前者孔隙体积和粗喉道占比较高,后者主要以细喉道为主;自生粘土矿物分割占据大量孔喉空间,自生伊利石主要为孔喉充填型,自生绿泥石主要为颗粒包壳型;珠海组储层与下渐新统恩平组烃源岩不整合接触形成纵向"下生上储"、横向连续分布的有利源储组合,烃源岩持续生烃.珠海组是典型的深埋藏碎屑岩低渗储层,仍具备良好的储集条件,储层发育受机械压实作用和自生粘土矿物共同控制;压实作用是原生孔隙损失的初始因素,以绿泥石和伊利石为代表的自生粘土矿物高度发育是制约优质储层发育的关键因素.      

鄂尔多斯盆地泾川地区三叠系延长组烃源岩特征及其沉积环境

泾川地区位于鄂尔多斯盆地西南缘,烃源岩发育情况尚不明确。通过野外地质调查和钻井岩心观察,结合烃源岩测试及元素地球化学资料,对长10—长7烃源岩进行评价,在环境分析的基础上研究影响烃源岩发育的主要因素。结果表明:研究区延长组烃源岩以长73泥页岩为最好,有机质类型以Ⅰ型和Ⅱ1为主,TOC为0.42%～29%;长10—长7泥岩有机质以Ⅱ2型为主,平均TOC含量低于2%;Ro为0.47%～1.08%,有机质基本已成熟。长10—长7烃源岩形成于温暖潮湿的环境,弱还原弱氧化的淡水介质条件,水深相对较浅。古生产力、沉积速率及水介质环境影响烃源岩发育。热水活动促进了古生物的繁盛,P、Cu含量及P/Ti值越高,有机质TOC含量越高。(La/Yb)N值越高,沉积速率越低,有机质越富集。Cu/Zn值越高,V/Cr值越高,Th/U值越低,水体还原性越好,有机质丰度越高。总之,热水活动提高了古生产力水平,相对较低的沉积速率有利于有机质的富集,还原性较强的水介质条件可使有机质得到良好的保存。陇县一带烃源岩因受陆源植物输入的影响,且形成环境不利,烃源岩品质相对较差。     

鄂尔多斯盆地盐池-定边地区长7烃源岩有机地球化学特征及沉积环境研究

通过对鄂尔多斯盆地盐池-定边地区长7段烃源岩的分析,研究区长7段烃源岩有机碳平均含量为3.22%,生烃潜量均值为12.8 mg/g,氯仿沥青“A”均值为0.55%,可以划分为较好-好的烃源岩,具有良好的生烃潜力。利用有机岩石学分析、热解分析,并结合饱和烃生物标志物分析,发现研究区长7段烃源岩有机质类型以Ⅱ₁型和Ⅱ₂型为主,有机质以菌藻类生源为主,并伴有部分高等植物生源。烃源岩有机质成熟度R_o值介于0.42%~0.76%之间,并且热解T_max也主要集中在440~455 ℃之间,并且正构烷烃分布特征及甾、藿烷异构化参数说明烃源岩有机质处于低熟-成熟度阶段。根据饱和烃中甾藿烷参数、三环萜烷参数、伽马蜡烷指数、β-胡萝卜烷相对含量以及姥植比参数特征,研究区长7段烃源岩沉积环境为湖相淡水弱氧化-弱还原环境。     

惠民凹陷岩浆作用对碎屑岩储层的影响

岩浆活动对碎屑岩储层的影响主要包括岩浆上拱作用、热烘烤作用和热液作用。岩浆上拱作用往往使上覆岩层中产生裂缝。而热烘烤作用使周围碎屑岩产生不同程度的变质,如使泥岩变质为板岩。轻微变质的板岩一般为有效封盖层,变质程度相对高的板岩,易发育裂缝而成为有效储集层。另外,岩浆活动造成局部地温梯度高异常,促使周围烃源岩热演化生成的烃类、有机酸、二氧化碳,与岩浆携带的无机二氧化碳一起注入周围碎屑岩储层中,使储层原始孔隙得以保留并产生次生孔隙。在基性岩浆侵入或喷溢活动中,岩浆中的Fe2+、Mg2+,有利于周围碎屑岩中的蒙脱石向绿泥石转化。而在酸性介质条件下,碎屑中长石颗粒蚀变提供的K+,有利于蒙脱石向伊利石转化。结果出现火成岩体周围储层中粘土矿物组合具富绿泥石而贫高岭石以及伊利石相对百分含量较高的特征。     

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

正~~     

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