Diagenetic Sequences Analysis of Fuyu Reservoir in Qijia-Gulong Depression,Northern Songliao Basin

Five paragenetic associations are recognized in Fuyu reservoir of Qijia - gulong depression of Daqing oil field: 1) detrital illite permeation, glauconite and pyrite precipitation; 2) feldspar dissolution, kaolinite precipitation and the incipient quartz overgrowths; 3) early calcite cements; 4) postdate quartz overgrowths and pore - filling quartz, authigenetic illite and chlorite formation, feldspar overgrowths, petroleum injections, K - feldspar and calcite cement dissolution; 5) pore - filling calcite and calcite replacement.     

Diagenetic Sequences Analysis of Fuyu Reservoir in Qijia - Gulong Depression, Northern Songliao Basin

Five paragenetic associations are recognized in Fuyu reservoir of Qijia - gulong depression of Daqing oil field: 1 )detrital illite permeation, glauconite and pyrite precipitation; 2 ) feldspar dissolution, kaolinite precipitation and the incipient quartz overgrowths; 3 ) early calcite cements; 4 ) postdate quartz overgrowths and pore - filling quartz, authigenetic illite and chlorite formation, feldspar overgrowths, petroleum injections, K - feldspar and calcite cement dissolution; 5) pore - filling calcite and calcite replacement.     

煤系烃源岩与石英次生加大边的形成机理探讨:以鄂尔多斯盆地东部山西组为例

借助有机酸热模拟、岩石薄片及阴极发光实验资料,分析了鄂尔多斯东部地区山西组煤系烃源岩与石英次生加大边的关系。研究表明:煤系烃源岩以Ⅲ型干酪根为主,在热演化生烃的过程中由于含氧基团逐步断裂产生了大量的有机酸;在酸性微孔隙环境下,石英砂岩及其岩屑石英砂岩中的火山喷出岩屑、长石等不稳定矿物易遭受溶蚀,形成的SiO₂提供了石英次生加大的硅质来源,薄片及阴极发光下均可观察到石英发育多期次生加大,尤以二期次生加大为主;证实煤系烃源岩中的有机酸是导致石英发生多期次生加大的直接原因,最终形成致密砂岩。      

基岩区断层泥的物质组成、定年方法与地震断层弱化机制研究进展

断层泥作为脆性断层活动的产物,是厘定断层的变形特征、形成时代与弱化机制的重要研究对象,在构造地质和地震地质等研究中具有重要意义。因此,全面了解断层泥的研究与进展,有助于基岩区古地震的研究。在系统收集和分析国内外相关资料的基础上,全面介绍了断层泥的矿物组成、石英形貌特征、定年方法与地震断层弱化机制等方面的研究进展,以及断层泥在基岩区地震断层研究中的应用。断层泥主要由黏土矿物(蒙脱石、伊利石、高岭石以及绿泥石等)与围岩矿物的碎粉和碎砾(石英、长石、云母、方解石、白云石等)组成。断层泥中的石英、伊利石与方解石是限定断层活动期次和形成时代的主要测试对象。目前断层泥定年方法主要包括石英微形貌特征分析法、石英ESR和OSL定年法、伊利石K-Ar或40Ar/39Ar定年法和方解石U-Pb定年法。地震断层的弱化机制研究主要涉及断层泥中矿物细粒化与新矿物形成、岩石组构的发育、断层摩擦生热、熔体形成与热增压等方面。      

Origin of red color of the Lower Siwalik palaeosols: A micromorphological approach

Palaeosols associated with fluvial of the Siwalik Group are and lacustrine deposits that occur as thick multiple pedocomplexes. The bright red color of the palaeosol beds has been earlier interpreted as a result of hot and arid palaeoclimate. However, as against this view, our investigations of the bright red palaeosol beds of the Lower Siwaliks suggest that the climate was cool and subhumid, instead of hot and arid during the deposition of these beds. Since cold climate is not very conducive to impart red coloration, further research is needed to explain the cause of these red beds. For this, the micromorphological study of soil thin sections was done which showed the presence of features such as dissolution and recrystallisation of quartz, feldspar and mica, compaction, slickensides, presence of calcite spars, subrounded and cracked nature of quartz grains, microfabric, complex patterns of birefringence fabrics, pigmentary ferric oxides, thick cutans and cementation by calcite. These features indicate that diagenesis took place on a large scale in these sediments. The positive Eh and neutral-alkaline pH of soils also suggest that the conditions were favorable for the formation of diagenetic red beds. During burial diagenesis of sediments, the hydroxides of ferromagnesian minerals got converted into ferric oxide minerals （hematite）. During deep burial diagenesis smectite was converted into illite and the preponderance of illite over smectite with increasing depth of burial also indicates the diagenesis of sediments. Thus, the red color of the Lower Siwalik palaeosols seems to be due mainly to the burial diagenesis of sediments and does not appear to be due to the then prevailing climatic condition.     

鄂尔多斯盆地中部延长组下组合流体包裹体特征和油气充注期次

通过对储层成岩作用、流体包裹体岩相学和孔隙沥青特征的分析,在烃包裹体期次划分的基础上,结合流体包裹体均一温度特征、烃源岩热演化史、地层埋藏史和储层成岩史,确定了鄂尔多斯盆地中部延长组下组合油气充注期次。结果表明:鄂尔多斯盆地中部延长组长8段和长9段致密储层主要发育压实、胶结、交代和溶解4种成岩作用,自生矿物主要为绿泥石、石英胶结物、长石胶结物和方解石胶结物。根据包裹体宿主矿物形成序列,识别出3期烃包裹体。第一期烃包裹体分布在石英愈合缝、石英次生加大边和充填孔隙的石英胶结物中,少数低成熟的黄色荧光烃包裹体及黑色荧光沥青包裹体代表了烃源岩进入生烃门限后排出的少量烃类充注,多数成熟度较高的蓝色、蓝白色荧光烃包裹体代表了生烃高峰期大量烃类充注;第二期烃包裹体分布在长石胶结物中,数量较少,显示蓝色和蓝白色荧光,在溶蚀孔隙周围或沿解理分布,呈短柱状,边界平直;第三期烃包裹体分布在方解石胶结物中,呈孤立或零星分布,形状近六边形;后两期烃包裹体均是在烃类充注结束后捕获孔隙中烃类形成的。研究区延长组长8段和长9段经历了晚侏罗世末期至早白垩世末期的一期烃类持续充注。     

CO2基增强型地热系统中流体-花岗岩相互作用研究进展及展望

CO₂与水相比,膨胀性大、黏度低、与岩石反应程度低,并且在作为增强型地热系统（EGS）渗流传热流体时,比水具有更高的换热效率。对CO₂-EGS生产过程中储层岩石物性变化的研究具有重要意义,从理论研究、实验研究、数值模拟3个方面,对CO₂基增强型地热系统CO₂-EGS中流体-岩石相互作用的研究现状进行了总结,并且从矿物成分、微观孔结构和力学性质3个方面对储层岩石性质的变化进行了评价。结果表明,CO₂-水-岩石相互作用参与反应的矿物主要为石英、长石类;而沉淀的矿物为蒙脱石、伊利石及方解石等。CO₂-水-岩石相互作用会导致储层岩石的力学性质下降,孔隙结构特征改变。最后,讨论了CO₂作为EGS渗流传热流体仍需攻克的难点问题,包括:CO₂的热动力学特征、换热效率,CO₂-水-岩石的相互作用及其对储层性质的改变,影响CO₂-EGS经济性的因素,以及CO₂-EGS数值模型的研究等。针对这些方面的研究可为今后CO₂-EGS的开发奠定基础。      

砂岩中碱性溶蚀研究进展

火山物质和长石碱性溶蚀形成的绿泥石、浊沸石、钠长石、伊利石等碱性自生矿物,是砂岩储层研究的重点,而碱性溶蚀本身却常被忽略。通过对碱性溶蚀机理、控制因素及成岩特征的分析,发现砂岩中发育石英颗粒碱性溶蚀、火山物质水解溶蚀、蒙脱石伊利石化导致的钾长石溶蚀、高岭石伊利石化导致的钾长石溶蚀和斜长石钠长石化5种碱性溶蚀作用,它们常与酸性溶蚀先后叠加发生,不易直接确定碱性溶蚀的类型和规模,常被忽略或误判为酸性溶蚀。依据碱性溶蚀与其伴生胶结物的成因关系,分析了部分含油气储层的碱性溶蚀类型及溶蚀规模,我国含油气盆地碱性溶蚀十分普遍,前4种碱性溶蚀形成的次生孔隙分别可达2%~7%, 5%~10%, 1.32%, 1.63%。      

塔中地区东河砂岩的成岩作用和孔隙演化

塔中地区下石炭统巴楚组东河砂岩储层主要为一套滨海沉积成因的石英砂岩，其平均成分组成石英８３％，长石８％，岩屑９％、以两口井为例，应用阴极发光、扫描电镜、Ｘ射线衍射和图象分析等测试手段，研究了区内东河砂岩的成岩作用，认为影响砂岩储集性能的主要成岩作用是压实、胶结和溶解作用。方解石的胶结和溶解决定了储层具有良好的孔隙性，溶解形成的次生孔隙是砂岩的主要储集空间。恢复的东河砂岩的原始孔隙度为３８％，经历３个阶段孔隙演化后的岩芯薄片计点孔隙度平均为１４％，岩芯物性分析孔隙度平均为１７％。     

The Mineral Composition and Sources of the Fine-Grained Sediments from the 49.6°E Hydrothermal Field at the SWIR

We used the X-ray diffraction method to determine systematically the mineral phases in bulk sediment samples and acid undissolved residuals of the fine-grained fraction of the surface sediments from the 49.6°E hydrothermal field at the Southwest Indian Ridge(SWIR)and discussed the mineral sources of the surface sediments.The results showed that the surface sediments in this region were composed of calcareous ooze,and calcite was the dominant mineral.The sediments also contained quartz,feldspar,clay minerals,pyroxene,sphalerite,barite,serpentine,and magnetite.The quartz,feldspar,and clay minerals were exogenous minerals that mainly originated from the Namib and Kalahari deserts in southern Africa.The pyroxene,serpentine,magnetite,sphalerite,calcite,and barite were endogenous minerals from weathering of seafloor basement rocks and seafloor hydrothermal activities.The sulfide particles in the sediments were mainly deposited from upwelling plumes.     

鄂尔多斯盆地东胜铀矿成矿作用研究

对东胜铀矿提出了物源、地层、古气候等3种成矿因素。岩相学与成矿矿物学研究表明,铀矿石中含有大量的方解石,并且长石与高岭石含量呈正相关,铀矿化与有机质也有一定的联系。结合铀矿地质特征初步分析认为,东胜铀矿是在氧化带铀元素以碳酸铀酰络合物搬运,在酸性介质条件下,还原带长石碎屑蚀变为高岭石,并有钙离子析出。当碳酸铀酰络合物从氧化带迁移到还原带,遇有大量钙离子时发生分解,出现铀矿石与方解石同时沉淀现象,有机质的还原作用也是铀矿沉淀的主要因素,经漫长的地质作用富集成工业矿体。     

致密砂岩酸性和碱性成岩环境特征及对储层物性的控制:以鄂尔多斯盆地临兴和神府地区为例

成岩流体酸碱性对砂岩次生孔隙的形成具有重要影响。从酸性和碱性成岩流体演化角度分析鄂尔多斯盆地上古生界致密砂岩成岩流体酸碱性对物性的控制作用。依据大量铸体薄片观察、扫描电镜、X衍射分析、常规物性测试和高压压汞，详细研究了鄂尔多斯盆地东缘临兴和神府地区上古生界致密砂岩的岩石矿物学特征、物性特征、成岩作用、孔隙成因类型和孔喉结构特征，探讨了致密砂岩储层酸性和碱性成岩流体环境的识别、分带、分布和发育的各类伴生孔隙，并分析了成岩流体环境的演化过程及物性响应特征。在埋藏过程中，工区上组合层系经历了碱性-酸性-碱性的成岩流体演变模式，下组合含煤层系经历了酸性-碱性的成岩流体演变模式。酸性成岩环境以长石溶蚀、石英加大和自生高岭石沉淀为主要特征，发育长石溶蚀孔、黏土矿物晶间孔等孔隙类型，孔喉半径较大，储层质量相对较好；碱性成岩环境以石英溶蚀、自生绿泥石沉淀为主要特征，以石英溶蚀孔、黏土矿物晶间孔为主要孔隙类型，孔喉半径较小，储层质量相对较差。酸碱过渡带致密砂岩储层介于两者之间。但是每类储层的物性和孔喉结构变化较大。成岩流体环境在纵向上呈现分带特征，自上而下发育碱性带、酸碱过渡带、酸性带、酸碱过渡带和碱性带，不同地区之间分带深度边界有差别；在酸碱过渡带中，局部地区发育酸性带、较弱酸性带和较弱碱性带。      

松辽盆地大庆长垣南缘四方台组砂岩型铀矿碳氧同位素特征及铀成矿意义

为进一步探讨松辽盆地大庆长垣南缘四方台组砂岩型铀矿的成岩环境、铀沉淀机制及成矿机理,通过钻井岩心观察,岩石薄片,含铀砂岩碳酸盐胶结物碳、氧同位素分析,对研究区砂岩岩石类型、碳酸盐胶结物类型、成岩阶段以及碳、氧同位素特征进行了系统研究。结果表明:含铀砂岩岩石类型为长石岩屑砂岩、岩屑长石砂岩,碳酸盐胶结物可分为3个期次,以第一和第二期次为主,胶结物包括方解石、铁方解石,见极少量含铁白云石。δ13C_PDB值为-22.45‰~-13.65‰,平均值为-18.33‰,δ18O_PDB值为-17.56‰~-9.46‰,平均值为-13.52‰,揭示有一定有机质参与;古盐度Z值介于75.98~90.97之间,为淡水沉积;古温度介于67.31~94.92℃之间,结合以上岩石特征、胶结物类型及成岩作用判定成岩环境处于早成岩—中成岩阶段A期。综合分析认为:早成岩阶段砂岩的压实、胶结作用使含铀砂岩孔隙度减小,抑制含氧富铀流体运移;随着成岩作用进行,埋藏深度增加,有机质成熟度升高发生热脱羧基作用,与压实作用产生的吸附水形成酸性溶液对长石、碳酸盐胶结物等进行溶蚀形成次生孔隙,增大砂岩孔隙度,促进含氧富铀流体下渗运移,下伏油气由断裂向上逸散,为地层提供还原剂,使铀在四方台组底部大规模沉淀和富集。      

天然水开放与封闭系统中CaCO_3溶解或沉淀的水化学后果比较

本文以4个水样的水化学分析结果为例,对开放系统与封闭系统中CaCO_3溶解或沉淀所造成的水化学后果进行了计算和比较;在此基础上,还对天然条件下水中CaCO_3溶解或沉淀可能造成的水化学结果进行了讨论.     

西宁盆地南部第三系含坡缕石粘土的地球化学特征

西宁盆地含坡缕石粘土赋存于第三系中,它由粘土矿物(伊利石、坡缕石、绿泥石等)、碳酸盐矿物(白云石、方解石)和陆源碎屑矿物(石英、长石、云母)组成。通过岩石化学统计相关系数和二次平差曲线对变化指数、相依系数、均方差研究,总结了坡缕石含量从东到西、从南到北增高的变化规律;碳氧同位素组成显示了湖相沉积特点,微量元素含量偏高,pH值8.75—9.23,反映了坡缕石形成环境为富镁弱碱—碱性的淡—咸水湖。研究了坡缕石的成矿地球化学作用,指出了寻找坡缕石的方向。     

Mineralogical study of surface sediments in the western Arctic Ocean and their implications for material sources

Mineralogical analysis was performed on bulk sediments of 79 surface samples using X-ray diffraction. The analytical results, combined with data on ocean currents and the regional geological background, were used to investigate the mineral sources. Mineral assemblages in sediments and their distribution in the study area indicate that the material sources are complex. （1） Feldspar is abundant in the sediments of the middle Chukchi Sea near the Bering Strait, originating from sediments in the Anadyr River carried by the Anadyr Current. Sediments deposited on the western side of the Chukchi Sea are rich in feldspar. Compared with other areas, sediments in this region are rich in hornblende transported from volcanic and sedimentary rocks in Siberia by the Anadyr Stream and the Siberian Coastal Current. Sediments in the eastern Chukchi Sea are rich in quartz sourced from sediments of the Yukon and Kuskokwim rivers carried by the Alaska Coastal Current. Sediments in the northern Chukchi Sea are rich in quartz and carbonates from the Mackenzie River sediments. （2） Sediments of the southern and central Canada Basin contain little calcite and dolomite, mainly due to the small impact of the Beaufort Gyre carrying carbonates from the Canadian Arctic Islands. Compared with other areas, the mica content in the region is high, implying that the Laptev Sea is the main sediment source for the southern and central Canada Basin. In the other deep sea areas, calcite and dolomite levels are high caused by the input of large amounts of sediment carried by the Beaufort Gyre from the Canadian Arctic Islands （Banks and Victoria）. The Siberian Laptev Sea also provides small amounts of sediment for this region. Furthermore, the Atlantic mid-water contributes some fine-grained material to the entire deep western Arctic Ocean.     

Mineralization Types of Gold in Central Inner Mongolia, China

IntroductionSo - called Central inner Mongolia in the papermeans the area including Daqing Mountains, WulaMountains, Serteng Mountains and the grasslandsnorth of the mountains. Tectonically it's located inthe western part at the northern margin of the Nor…     

Mineralization Types of Gold in Central Inner Mongolia, China

There are four mineralization types of gold in Central Inner Mongolia: mylonite type, quartz vein type, quartzpotash- feldspar vein type and alteration type.Ore bodies of mylonite type were controlled by ductile shear zone. Both of ore and gangue minerals were undergone ductile deformation. Mineralization age is about 2040Ma and represents the metallogenetic process in deep tectonic level.There are three types of quartz veins differed from genesis mechanism. Small scaled, lens- shaped quartz veins formed during ductile shearing are found in mylonite ore bodies. Decation quartz veins are in the ore bodies of alteration type. Infiltration quartz veins are main gold- bearing bodies for some gold deposits such as Bainaimiao and Saiwusu gold mines. It also occurred in many other deposits from the middle Proterozoic to the Mesozoic.Quartz potash- feldspar veins are observed in the Palaeozoic and occurred in middle tectonic level.Gold deposits of alteration type such as Donghuofang and Saihudong occurred in shallow tectonic level of the Mesozoic.In short, from the Proterozoic to the Mesozoic, mineralization types varied from mylonite type to quartz potash- feldspar vein type and to alteration type. Gold - bearing quartz veins changed from syn - ductile - shearing quartz vein to infiltration vein and to decation quartz vein. Mineralization developed from deep to middle and to shallow level.     

渝东石柱地区龙马溪组页岩纤维状脉体成因

渝东石柱地区志留系龙马溪组页岩地层发育特殊的纤维状方解石脉体。为揭示其流体来源及形成机理，结合岩石学及地球化学特征等开展系统分析。研究表明，纤维状方解石脉（FCV）以顺层或近平行层面充填于黑色粉砂质页岩和泥质粉砂岩微裂缝中，脉体宽0.1~4.0 cm、横向延伸一般为0.5~8.0 m。纤维状方解石晶体以柱状、纤维状垂直裂缝壁生长为主，多与石英共生产出。晶体表面洁净，局部见方解石压力影、机械双晶及晶体间锯齿状晶界。阴极发光下纤维状方解石呈暗红色-橘红色；碳-氧同位素分析表明δ13C_PDB略偏负、δ18O_PDB负异常明显（δ13C_PDB、δ18O_PDB平均值分别为-1.549‰及-12.654‰），指示其形成过程中受温度升高影响明显；流体包裹体均一温度平均值为159.5℃。结合区域构造-热演化史分析，结果表明石柱地区龙马溪组FCV形成流体具造山带同构造期超高压有机流体性质特征，为中-晚三叠世印支期同构造作用驱动深部流体叠加生烃超高压释放导致水力压裂所致，裂缝的开启导致孔隙流体的过饱和及纤维状方解石的快速沉淀。      

基于纳米尺度的碎屑岩骨架矿物结构研究

对胜利油田胜坨地区碎屑岩储层岩芯样品和岩石薄晶片分别采用场发射扫描电镜、透射电镜进行镜下观察与能谱测试分析.结果表明:碎屑岩中骨架矿物石英和长石中存在纳米尺度的结构特征;石英镜下可见类蚀像凹坑、雏晶单晶、平行脊线、晶体位错、类包裹体晶内核等5种纳米尺度的结构;长石镜下可见晶面平行凹痕、溶蚀针、纳米级薄层断阶、长石高岭石化、晶体位错和超微包裹体等6种纳米尺度的结构;这些结构大多在几百纳米的尺度范围内,有的甚至只有几十纳米;矿物在纳米尺度上表现出的结构特征与其本身的硬度变化、晶体晶格缺陷、晶体生长过程以及成岩作用的显微表现和显微构造应力改造作用有关.对碎屑岩骨架矿物中纳米尺度结构特征的进一步研究有望为岩石显微变形的应力作用机制和方式以及溶解作用等成岩作用模式做出有效分析,进而为油气勘探开发提供新的探索方式.