Phanerozoic Microbialites often occur before and flourish after extinction events,indicating that there is a negative correlation between microbialites and metazoans,and their succession processes are closely related to major biological events.In addition,many large oil and gas fields have been discovered in the microbialites reservoirs,which has led to increasing attention paid to the study of microbialites.At present,the research of the relationship between the microbialites succession and the Great Ordovician Biodiversification Event(GOBE)has become one of the frontier hotspots of global research.This paper summarized the research progress of Ordovician microbialites in recent years,and discussed the relationship between microbialites succession and metazoan diversity,as well as the main controlling factors affecting their changes.The factors affecting the succession of Ordovician marine microbialites include intrinsic biological factors(such as bioturbation,microbial and metazoan symbiosis)and external environmental factors(such as palaeogeographic evolution,global cooling,enhanced nutrient supply from continental weathering,sea level rise,increased dissolved oxygen,and decreased carbonate saturation).The existing problems in the study of Ordovician marine microbialites are analyzed,and pointed out that micro-factors such as microbial community types and fabric evolution that affect the development of marine microbialites may be the focus of future research.Meanwhile,the different manifestations of the interaction between microbialites succession and metazoan radiation,and even the interaction with the four spheres of the Earth(biosphere,lithosphere,hydrosphere,and atmosphere)on different continents,more interdisciplinary research may be needed,which is of great significance for studying the main controlling factors of marine facies microbialites succession and the paleo-environment and paleoclimate during their formation.

Based on the latest drilling core, thin section, 3D seismic, well logging data as well as exploration results, the sequence stratigraphy and sedimentary microfacies of the Middle—Lower Ordovician carbonates in Gucheng area, and their controlling effects on the development of reservoir were examined by the theories and methods of fine carbonate sedimentology. The results show that the Middle—Lower Ordovician in Gucheng area is a set of typical carbonate ramp deposits, which can be divided into 10 microfacies in 4 subfacies as follows: back ramp, inner shallow ramp, outer shallow ramp, and deep ramp. The back ramp subfacies consists of muddy-dolomitic flat and dolomitic lagoon microfacies; it is dominated by lamellar micrite dolomite tight in lithology. The inner shallow ramp subfacies includes dolomitic shoal and dolomitic flat in shoal top and dolomitic flat between shoals microfacies; it is mainly composed of crystal dolomite with metasomatic residual structure, as well as abundant karst vugs and intercrystalline pores. The crystal dolomite has an average porosity of 4.36%. The outer ramp subfacies includes medium—high and low energy grain shoal and inter-shoal microfacies; it is dominated by sandy limestone, oolitic limestone, and micrite limestone with few pores. The deep ramp subfacies is dominated by low-energy argillaceous deposits, with local presences of storm shoal microfacies. The Lower—Middle Ordovician has six third-order sequences from bottom to top, among which sequence (SQ3) represents the third member of Yingying Formation. The main reservoir has three fourth-order high-frequency sequences. Apparently, the favorable reservoir in the study area is jointly controlled by sedimentary microfacies and high frequency sequence in the carbonate ramp. The former controls the primary pore structure, and the latter controls the intensities of karstification exposure and dolomitization in the penecontemporaneous period. The dolomitic shoals and top dolomitic flats of different stages, superimposed and connected into favorable reservoirs of considerable scale like "platform margin", are favorable exploration facies in the carbonate ramp.

四川盆地中二叠统茅口组一段(简称茅一段)眼球状灰岩在盆内广泛分布,以"眼球灰岩"与"眼皮灰岩"的快速交替发育为特征.近年来,借鉴非常规天然气勘探思路,四川盆地各地区天然气勘探在茅一段相继取得大的突破,钻采成果表明,泥灰岩(眼皮灰岩)储层含气性较好,具有较大的勘探潜力.但长期以来,茅一段被认为是一套良好的烃源岩,忽视了其作为非常规储层的巨大价值.基于四川盆地中部合川—潼南地区2口最新钻井资料以及对周边野外露头观测,对茅一段泥灰岩储层特征进行了详细分析,结果表明:茅一段泥灰岩储层的储集空间类型丰富,孔隙以中孔为主,孔隙间连通性中等;总有机碳含量相对较高,有机质热成熟度高,生烃条件好,为一套具有自生自储成藏特征的非常规碳酸盐岩储层.在此基础上,建立了泥灰岩储层评价标准,并对泥灰岩储层进行初步评价,认为茅一段泥灰岩普遍满足储层成藏的基本条件,部分满足有利储层形成条件,具有进一步勘探开发价值.

The biodiversity changes of trilobites in the middle Yangtze region of South China in the Great Ordovician Biodiversification Event and the end-Ordovician mass extinction have been analysed. The Ordovician trilobites in this region originated in the early Tremadocian and radiated from the late Floian to the early Katian. Two peaks of diversity appeared in the late Dapingian to the early Darriwilian and the early Katian. The extinction occurred in the late Katian, followed by a survival period in the Hirnantian. The Whiterock fauna began to surpass the Ibex fauna during the early Katian and were dominant by the late Katian to the Hirnantian, indicating that Cambrian Evolutionary Fauna was gradually replaced. The study once again confirms the view that the effects of factors such as sea level, climate, oxygen content, nutrient supply, and tectogenesis differ temporally and to different degrees in different regions, resulting in differences in the vertical sequence and horizontal combination of ecosystems, which is the reason for the different evolution patterns of Ordovician trilobites in different regions.

文章以项目团队指导的长江大学地学专业本科生参与的"大学生创新创业计划"为具体对象,研究与构建适合大学生科研创新能力培养的PBL培养模式,开展教学实践研究与教学效果评价,最后提出有效应用基于PBL大学生科研人才培养模式的对策与建议.

四川盆地中二叠统茅口组一段具有较大的天然气勘探潜力,但一直存在沉积相认识不清的问题.基于四川盆地中部2口最新钻井岩心厘米级精细描述以及多个野外露头观测,结合分析化验资料及测井曲线,开展了详细的沉积相标志分析,提出了新的茅一段沉积相划分方案."眼球灰岩"与"眼皮灰岩"的主要区别在于泥质含量的多少,用自然伽马曲线能够有效区分这2种岩相;海相缺氧环境、大量风暴沉积构造以及硅质生物碎屑表明,茅一段沉积于缓坡型碳酸盐岩台地环境之下,受到风暴作用及与之伴生的风暴上升流的影响.基于沉积相标志,将茅一段划分为中缓坡外带和外缓坡上部2个亚相,中缓坡外带包括风暴碎屑流、风暴滩、风暴滩间洼地3个微相,外缓坡上部"眼皮灰岩"含量较高,微相组合为颗粒流、静水泥夹碎屑流,一般发育在茅一段上部或顶部.

系统研究了湖北省西部新滩剖面亚丁斯克阶至长兴阶的腕足动物群落演替过程.通过研究区与华南地区及特提斯区域进行比对分析,结合前人对碳、氧同位素的研究结果,分析了二叠纪腕足类群落演替的规律和区域差异.结果表明:除二叠纪末的灭绝事件,在乌拉尔统与瓜德鲁普统界限附近及乐平统中共识别出两次腕足类种群的显著分异度变化,且其演替时间都接近6～8个百万年.前一次体现在冷水种与暖水种的混合过渡现象,后一次体现在个体增大、壳饰发育与个体变小、壳体变薄的不同分化现象.在气候方面,冰期与季风的强弱作为主要因素从温度及养分来源共同影响腕足类的多样性变化.火山喷发事件及板块运动改变腕足类生态环境并造成区域的分化.海平面变化既受气候影响也受地壳运动影响,高频的海平面变化不断改变着腕足类在研究区的生存空间.腕足类在适应不同环境中所发生的壳体形态改变、群落结构演替很好的展示了生物环境对古环境的响应.

The evolution of Ordovician cephalopod diversity in the Middle Yangtze region of South China has been analysed. The cephalopods in this region appeared in the earliest Tremadocian, radiated in the Early–Middle Floian and Middle Ordovician, and went through an extinction period during the Late Katian and Hirnantian. The composition of the cephalopod fauna underwent major changes in the Late Floian. Specifically, all the genera occurring in previous time periods disappeared and Tarphyceratida, Actinoceratida, and Orthoceratida appeared and prospered. Differences in the evolution of cephalopod diversity between Middle Yangtze region and other regions were detected, which were caused by differences in the vertical sequence and horizontal combination of controlling factors. Changes in living environments and the distribution of food resources prompted Ordovician cephalopods to evolve adaptations for life in deep-water environments. The low-temperature ocean current near the western coastline of Gondwana created favourable conditions for the Floian peak of cephalopod diversity in South China. The tectonic movements, high rainfall, and relatively closed environment of the Middle Yangtze region led to rapid sea level rise and hindered cephalopod diversification. These processes explain the low cephalopod diversity in the Late Ordovician and the absence of the previously reported Katian radiation peak in this region.

为探讨鄂西地区震旦纪寒武纪之交的沉积转换机制,对鄂西长阳黄家坪、鹤峰白果坪岩家河组底部层状硅质岩通过主微量(含稀土)元素测试开展成因分析.按元素地球化学特征将硅质岩分为2类:Ⅰ类硅质岩具有相对较高SiO2质量分数(平均96.75％),较低的Al2 O3质量分数(平均0.13％)与TiO2质量分数(小于0.01％),Al/(Al+Fe+Mn)在0.36～0.88之间,氧化物双变量图解落入生物成因硅质岩区;富集亲下地壳和地幔元素Ni、Co、Ag、V和热水沉积敏感元素Sb、As、Ba、U等;稀土总质量分数较低,重稀土富集,具有Ce轻度负异常(平均0.74)和Eu正异常(平均1.56),经北美页岩标准化后稀土元素配分曲线表现为左倾,应为受热水作用影响的生物成因硅质岩;Ⅱ类硅质岩具有相对较低的SiO2质量分数(平均85.77％),较高的Al2 O3质量分数(平均4.06％)与TiO2质量分数(平均0.20％),Al/(Al+Fe+Mn)在0.63～0.95之间,氧化物双变量图解更接近火山成因硅质岩区;富集亲下地壳和地幔元素Cr、Ni、Co、Ag、V和热水沉积敏感元素Sb、As、Ba、U等;稀土元素质量分数相对较高,具有Ce轻度负异常(平均0.76)和Eu轻度负异常(平均0.85),经北美页岩标准化后稀土元素配分曲线变化平缓,应为受火山作用影响的硅质岩.结合前人报道鄂西地区寒武纪初岩家河组、牛蹄塘组下部火山作用、热水沉积的相关记录,认为层状硅质岩的形成主体应为早寒武世初期兴凯运动在鄂西地区的构造响应,兴凯运动对鄂西地区沉积转换、烃源岩形成有重要的控制作用.

The evolution of the Early–Middle Ordovician brachiopod diversity in the middle Yangtze region of South China has been analyzed. The brachiopods in this region originated in the early Tremadocian and radiated from the late Floian to the late Dapingian. The composition of rhynchonelliformean brachiopods underwent major changes in the late Floian, and endemic genera migrated from the upper Yangtze region to replace the cosmopolitan genera. A global comparison of the brachiopod diversity curves of South China, Laurentia, and Baltica reveals that (1) the processes and scales of brachiopod radiation in different paleocontinents were distinct; (2) unlike the global evolution of graptolites and chitinozoans, the correlation between brachiopod diversification and regional habitat change was more obvious, and the impact of habitat heterogeneity was reflected not only between plates but also in the interior of the plates, such as the closely connected middle and upper Yangtze regions of South China; and (3) geographical isolation was a key factor in the differential radiation on different paleocontinents.

下三叠统飞仙关组是鄂西渝东地区天然气的主要产层.根据代表性探井J69井、J38井、J61井、XD1井的储层物性及储集空间特征分析,结合普通薄片、铸体图像、阴极发光、扫描电镜、碳氧同位素分析等技术对储层特征及成因进行了研究.研究发现,鄂西渝东地区飞仙关组中缓坡浅滩和浅缓坡浅滩储层形成过程差异性较大;中缓坡浅滩在海底胶结作用之后直接进入埋藏阶段,经过进一步胶结、新生变形以及压溶之后仍存在有效孔隙并不同程度被沥青充填,在晚期埋藏溶蚀后形成现今储层,具有物性相对较差但规模相对较大的特点;浅缓坡浅滩在海底胶结作用之后,发生准同生期的多次间歇性暴露,形成淡水溶蚀改造层,在浅埋藏阶段叠加白云石化,白云石化作用主要沿间歇暴露面进行,而流体主要来自飞仙关晚期的蒸发台地,深埋阶段在埋藏溶蚀改造之后形成现今储层,具有物性总体相对较好但规模相对较小的特点.

In order to increase shale gas production, the mechanism of CO2 flooding in low permeability reservoirs was investigated by experiments to find out the effect of CO2 flooding on the formation. Experiment results showed that with the increase of pressure, the amount of dissolution increased, and the porosity of core also increased. The results also showed that, through CO2 flooding, the porosity was improved to increase the permeability, and the production of shale gas was ultimately increased.

This study is the first systematic assessment of the Lower Ordovician microbial carbonates in Songzi, Hubei Province, China. This paper divides the microbial carbonates into two types according to growth patterns, namely nongranular and granular. The nongranular types include stromatolites, thrombolites, dendrolites, leiolites and laminites; the granular types are mainly oncolites and may include a small amount of microbiogenic oolite. According to their geometric features, the stromatolites can be divided into four types: stratiform, wavy, columnar and domal. Additionally, dipyramidal columnar stromatolites are identified for the first time and represent a new type of columnar stromatolite. The thrombolites are divided into three types: speckled, reticulated and banded. The grazing gastropod Ecculiomphalus and traces of bioturbation are observed in the speckled and reticulated thrombolites. This paper considers these two kinds of thrombolites to represent bioturbated thrombolites. These findings not only fill gaps in the field of domestic Ordovician bioturbated thrombolites but also provide new information for the study of thrombolites. Based on the analysis of the sedimentary characteristics of microbialites, the depositional environments of the various types of microbialites are described, and the distribution patterns of their depositional environments are summarized. The relationship between the development of microbialites and the evolution and radiation of metazoans during the Early to Middle Ordovician is discussed. Consistent with the correspondence between the stepwise and rapid radiation of metazoans and the abrupt reduction in the number of microbialites between the late Early Ordovician and the early Middle Ordovician, fossils of benthonic grazing gastropods (Ecculiomphalus) were found in the stromatolites and thrombolite of the study area. It is believed that the gradual reduction in microbialites was related to the rapid increase in the abundance of metazoans. Grazers not only grazed on the microorganisms that formed stromatolites, resulting in a continuous reduction in the number of stromatolites, but also disrupted the growth state of the stromatolites, resulting in the formation of unique bioturbated thrombolites in the study area. Hydrocarbon potential analysis shows that the microbialites in the Nanjinguan Formation represent better source rocks than those in the other formations.

介绍了油田疏松砂岩的储层特征,分析了速敏、水敏、油水乳化堵塞及固相颗粒侵入等储层主要伤害因素.目标区块储层存在较严重的速敏和水敏损害现象;当钻完井液滤液与原油的体积比为3∶7时,油水乳化堵塞现象较严重;钻井液固相颗粒侵入深度和损害程度随天然岩心渗透率的增大而逐渐增强.提出了储层保护措施,优选了黏土稳定剂、防乳破乳剂及暂堵剂,研究出1套适合疏松砂岩油藏的油气层保护钻井液体系,进行了室内评价试验.结果 表明:该钻井液体系具有较好的储层保护效果,对不同渗透率的天然岩心,使用该钻井液体系污染后,渗透率恢复值均能达到90％以上,能够满足疏松砂岩储层钻井对储层保护效果的要求,保障了油田的高效稳定开发,同时为疏松砂岩油藏的高效合理开发提供了理论依据和技术支持.

以高分辨率层序地层学为基础,并结合测井和岩心资料,通过识别旋回界面标志,将研究区的短期基准面旋回层序类型总共划分成3种类型:即向上“变深”的非对称短期旋回,向上“变浅”的非对称短期旋回和对称型短期旋回.文中详细讨论了每种亚型的沉积背景、叠加方式在沉积相中的分布以及测井曲线特征.并在此基础上,分析总结出在上油砂山中短期旋回的分布,指出上油砂山组整体上处于一个湖退的环境,并向河流相过渡.

The Early Ordovician stromatolites in the study area are mainly exposed at the bottom and middle and lower parts of the Second Member of Nanjinguan Formation, the top of the Fourth Member of Nanjinguan Formation, the middle of the Second Member of Fenxiang Formation and the bottom of the First Member of Honghuayuan Formation. In order to find out the controlling factors of Lower Ordovician stromatolites development in the study area, the analysis data of carbon, oxygen isotope samples, macro element samples as well as their variation characteristics are studied and then combined them with previous research results, which is eventually beneficial for reaching the conclusion: sea level change is one of the main factors controlling the formation of stromatolites. There are five sea level change cycles in the Early Ordovician period. The analysis of sea level change and accommodation space variation characteristics show that when the growth rate of the accommodation space is approximately equal to that of carbonate, the circulation of seawater is well, and the amount of light and oxygen is sufficient, so that the cyanobacteria organism can be multiplied in large quantities. The growth and development provide favorable conditions, and favorable conditions are provided for the growth and development of stromatolites; The peak changes in CaO content and CaO/MgO ratio indicate that the formation period of stromatolites is arid climate environment with high water temperature and large evaporation. Prokaryote reproduction is suitable for the environments with high seawater cleanliness. When the amount of land-based debris injected into the sea increases, the turbidity of water will lead to a large number of deaths of algae microorganisms that form stromatolites, and the stromatolitic microbial mats cannot be preserved. In addition, the growth and predation of macro-organisms play a restrictive role in the development of stromatolite-forming micro-organisms blue-green algae. According to the actual situation of the development of the laminated rocks in the study area, what is the dominant function in the formation and decline of stromatolites between the evolution of metazoans and changing environments is discussed in the study.

研究区早奥陶世叠层石主要出露在南津关组二段底部、中下部,南津关组四段顶部,分乡组二段中部,红花园组一段底部.通过对研究区样品碳氧同位素、常量与微量数据分析结合其变化特征及资料分析得出如下结论:海平面变化是控制叠层石形成的主要因素之一,早奥陶世存在5个海平面变化旋回;沉积环境因素的影响还表现在水体盐度、温度、陆源碎屑物质供给三个方面,通过对水体环境的影响进而影响叠层石的生长发育.此外,宏体生物生长捕食作用对形成叠层石的微体生物蓝绿藻的发育起着制约作用.结合研究区的叠层石发育实际情况,对比论述了后生动物的演化和环境因素在叠层石的形成与衰减的过程中谁占主导作用.

系统性地对湖北松滋地区下奥陶统叠层石特征进行的详细研究.结果显示,叠层石在研究区下奥陶统南津关组、分乡组和红花园组均有分布,在纵向上具有规模、厚度和数量逐渐减小的特征,横向上叠层石类型也发生有规律的变化,由水平层状、波状逐渐变为柱状的类型.新发现并命名了两种叠层石类型,即凝块状叠层石和双锥柱状叠层石.根据几何形态特征,可以将研究区的叠层石分为层状、波状、柱状、丘状以及凝块状五种类型.在对各类型叠层石的沉积特征进行详细阐述基础上,根据叠层石发育的形态类型,结合不同类型叠层石内部的岩性、微相及显微特征,对研究区各类叠层石沉积环境进行了分析,并总结了研究区叠层石的沉积模式.根据中奥陶世初期后生动物的大量增加与叠层石突然减少的对应关系,结合研究区叠层石中发现大量后生底栖食草腹足类Ecculiomphalus化石等现象,认为叠层石的逐渐减少、衰退与后生动物丰度增加有一定关系,食草动物不仅啃食了形成叠层石的菌藻类微生物,造成叠层石数量的不断减少,而且破坏了叠层石的生长状态,并形成了独具研究区特征的凝块状叠层石.此外,研究认为,中奥陶世开始,海平面的快速上升也是研究区叠层石减少直至消失的原因之一.

为研究阿拉尔地区古近纪—新近纪地层结构及环境特征,在野外岩芯观察和描述的基础上,对研究区地层结构类型进行划分和形成机理解释,识别出各时期地层结构类型并结合古生物特征,最终进行环境特征综合分析.结果表明:地层结构包括均质型和非均质型(互层式、夹层式、进积型、退积型和无序多层式);各地层结构的形成与沉积物供给速率同可容空间速率之间的对比差异有关;下干柴沟组—下油砂山组时期识别出扇三角洲平原和滨浅湖2种沉积亚相及部分微相类型,表现为扇三角洲平原和滨浅湖交替沉积,湖平面多次升降旋回,气候经历了温凉干旱—暖热—半干旱—干旱加剧,水体逐渐成化,沉积环境由还原转向氧化.

湖北松滋刘家场地区寒武系覃家庙组三段发育层状、不规则层状和柱状叠层石,三游洞组发育柱状和半球状叠层石.从层状、不规则层状、柱状到半球状叠层石,内部灰泥含量不断减少,纹层特征从明显到断续,反映了水动力条件加强的变化环境.从沉积岩石学角度与叠层石分类观点讨论得出,研究区不同沉积环境的叠层石组合类型有所差异,不同类型的叠层石主要沉积相带不同:潮上带主要分布层状(包括不规则层状)和柱状叠层石,潮间带主要分布柱状、半球状叠层石;层状叠层石主要分布于水动力条件较弱的潮上带,而柱状和半球状叠层石主要分布于水动力条件较强的潮间带下部.部分后生动物的大量灭绝导致叠层石微生物生长繁殖是松滋寒武系叠层石发育的主要原因.