“巨型油气田”指在目前已知技术条件下，最终探明可采储量达到或超过0.68×10⁸t的油气田。本文在系统调研全球巨型油气田勘探与研究现状基础上，依托IHS、C&C数据库及国内外公开发表的相关文献资料，对截至2009年底的320个海相碳酸盐岩巨型油气田及其赋存的48个含油气盆地进行详细分析，重点探讨其发育的构造环境及其富集的盆地类型。构造环境主要包括伸展、挤压、走滑3种，应用Paul Mann提出的含油气盆地类型划分方案。研究表明，海相碳酸盐岩巨型油气田主要形成于伸展构造环境，包括大陆裂谷与上覆凹陷、面向大洋盆的被动大陆边缘2种类型盆地。伸展构造环境有利于优质烃源岩、有效储集层、良好盖层的形成及生储盖的有效配置。国外海相碳酸盐岩巨型油气田勘探带给我们的启示是:加强我国伸展构造环境下这2种类型原型盆地研究，尤其是盆地演化早期阶段裂谷的研究，这将对我国海相碳酸盐岩的油气勘探具有重要的指导意义。

<p>The giant fields are considered to be those with estimated ultimate recoverable hydrocarbons of equal or more than 680 million tons.On the basis of systematically surveying the status&nbsp; of the global giant field exploration and research,using the IHS and C&C databases and related literature on public publication,the paper analyses the 320 marine carbonate giant fields with their occurrence of 48 petroliferous basins by the end of 2009 in detail,with an emphasis on the plate tectonic setting and accumulation basin type.Plate tectonic setting includes divergent,convergent and transform,and the petroliferous basin classification of Paul Mann is used here.Research indicates that marine carbonate giant fields are formed mainly in divergent tectonic setting,including continental rifts and overlying sag,continental passive margins fronting major ocean basins.Divergent tectonic setting is favour of the forming of high quality source rocks,effective reservoir,good seal and effective assembly.The exploration inspiration is that enhancing the study of above-mentioned prototype basins in divergent tectonic setting,especially the rift&nbsp; at the early stage of basin evolution,which will guide our marine carbonate petroleum exploration.</p>

古生界海相碳酸盐岩油气对中国能源安全具有重要意义。以全球古生界海相碳酸盐岩大油气田的最新资料为基础,系统统计分析了古生界海相碳酸盐岩大油气田的地质特征及其分布规律。截至2013年底,全球15个含油气盆地中共发现了89个古生界海相碳酸盐岩大油气田,油气可采储量达495.9&times;10⁸,t油当量,占全球海相碳酸盐岩层系油气总储量的20.9%。研究表明,大油气田分布在中东、前苏联、北美和亚太地区,其中,大油田主要分布于前苏联和北美,大气田则主要位于中东和亚太,20世纪70年代是大气田发现的高峰期。大油气田的油气主要来自古生界烃源岩,以志留系、石炭系、二叠系和泥盆系(按重要性排序)为主;烃源岩岩性主要为泥页岩、沥青质泥页岩和沥青质碳酸盐岩。盖层以蒸发岩和碎屑岩为主。层系上,油气主要富集于二叠系、石炭系和奥陶系,白云岩和生物礁储集层占重要地位。埋深上,储量分布相对集中的埋深为2500~3000,m、3500~4000,m和4000~4500,m,分别占总储量的52.6%、15.9%和9.5%。油气藏类型上,以构造圈闭为主,不过近年来发现的大油气田的非构造圈闭比例有所增大。建议中国古生界海相油气勘探应重视白云岩储集层,更重要的是,应加强深层海相碳酸盐岩层系油气成藏机理和分布主控因素的研究。

<p>Exploration for petroleum in the Paleozoic marine carbonate rocks is of great significance to China&rsquo;s energy security. Based on the analysis of the newest data for oil-gas fields,this study attempts to document the geological features and distribution patterns of giant marine carbonate rock oil-gas fields in the Paleozoic throughout the world. A total of 89 giant marine carbonate rock oil-gas fields in the Paleozoic had been discovered in 15 basins in the world by the end of 2013. Recoverable oil and gas reserves in these giant fields amount to 495.9&times;10⁸ t oil equivalent,which make up 20.9% of the total recoverable reserves in all marine carbonate rock fields in the world. Results show that giant oil-gas fields mainly occur in the Middle East,former Soviet Union,North America and Asia Pacific,of which, giant oilfields are mainly distributed in former Soviet Union and North America,while giant gas fields are mainly confined to the Middle East and Asia Pacific. The peak discovery of giant gas fields occurred in 1970s. Oil and gas in the giant oil-gas fields were largely derived from the Paleozoic source rocks. In terms of relative importance,the most important source intervals are the Silurian, Carboniferous, Permian and Devonian. The source rocks are dominated by mudstones and shales,bituminous mudstones and shales and bituminous carbonate rocks. Evaporites and clastic rocks are the dominant seal rock. Stratigraphically,the reserves are concentrated in three stratigraphic units: the Permian, Carboniferous and Ordovician. Dolostone and reef reservoirs are of particular significance. The petroleum reserves are largely accumulated in three stratigraphic units of burial depths: 2500~3000,m(hosting 52.6% of the total),3500~4000,m(15.9%),and 4000~4500,m(9.5%). Structural traps are the main trap types for the giant oil-gas fields,but the proportion of non-structural traps has increased for the newly discovered giant oil-gas fields. For marine hydrocarbon exploration in China,it is suggested that a greater attention should be paid to dolostone reservoirs. More importantly,the studies of hydrocarbon accumulation mechanism and controlling factors for hydrocarbon distribution in deep marine carbonate strata should be strengthened.</p>

与国外相比，中国海相碳酸盐岩具有克拉通地块小、年代老、埋藏深、改造强等特点，面临台内、内幕、台缘与深层古老层系油气勘探潜力评价等理论技术难题。文章依托国家油气重大专项“十一五”至“十三五”碳酸盐岩项目和中国石油天然气集团有限公司碳酸盐岩储层重点实验室，围绕碳酸盐岩沉积储层开展了有针对性的理论技术攻关，取得4 项认识创新：（1）小克拉通台内普遍发育裂陷，沉积分异助推勘探领域由台缘拓展至台内；（2）发现内幕岩溶储层新类型，助推勘探领域由局部潜山区拓展至广泛的内幕区；（3）深层碳酸盐岩储层具相控性，决定储层分布的规模性和可预测性，推动勘探领域由浅层拓展至深层；（4）古老微生物碳酸盐岩具“三元”控储控分布特征，推动拓展了中—新元古界和寒武系盐下油气勘探新领域。上述理论进展填补了国内外碳酸盐岩沉积储层研究的认识空白，同时为塔里木盆地塔中、轮古、哈拉哈塘、顺北和四川盆地普光、元坝与安岳等大型油气田的发现所证实。

Different from foreign countries, the marine carbonate rocks in China are featured by development in small craton block, old geologic age, deep burial depth, and strong transformation, and the theory and technology are faced with problems in the evaluation of oil and gas exploration potential in the intraplatform, intra-carbonate strata, platform margin and old strata in deep formations. By relying on the carbonate reservoir project of national oil and gas special projects during the 11^th and 13^th Five-Year Plan periods and CNPC Key Laboratory of Carbonate Reservoirs, the targeted theoretical and technological researches on carbonate reservoir have been conducted, and innovative understanding has been achieved in four aspects, including: (1) The rifts are generally developed in the intraplatform of small cratons and the geological knowledge of sedimentary differentiation promotes the expansion of exploration field from platform margin to the intraplatform; (2) The discovery of new types of intra-carbonate karst reservoir promotes the expansion of exploration field from the local buried hill to the broad intra-carbonate strata; (3) The deep carbonate reservoir is controlled by sedimentary facies, consolidating the large&nbsp;scale and predictability of reservoir, which understanding promotes the expansion of exploration field from shallow to deep formations; (4) The geological understanding of “ternary” reservoir controlling and distribution of the ancient microbial carbonate rocks promotes the expansion of new exploration fields in the Meso-Neoproterozoic and subsalt Cambrian. The above theoretical progress supports to fill the gap in the field of carbonate reservoir study at home and abroad, and is confirmed by the discovery of large oil and gas fields such as Tazhong, Lungu, Halahatang, Shunbei in Tarim Basin, and Puguang, Yuanba, and Anyue in Sichuan Basin.<br><br>

碳酸盐岩地层-岩性大油气田是一种重要的油气田类型，勘探已经证实其在全球范围内有着大量的油气资源及油气产量。通过对全球94个碳酸盐岩地层-岩性大油气田的区域展布、层系分布、圈闭类型、储层埋深及储量规模等参数的分析，探讨了其分布的主控因素。这类油气田主要分布于北美、中东和中亚地区，其中北美含油气域的油气最为富集，主要富集层系为奥陶系、石炭系、古近系和新近系。圈闭类型主要为生物礁类、颗粒滩类、成岩圈闭和不整合与风化壳型；埋深一般小于5 000 m，埋深超过5 000 m的油气田仅占6.4%。本文重点探讨了以下5个关键因素对碳酸盐岩地层-岩性大油气田的形成与分布：①稳定局限的浅水环境、中低纬度有利于有机质的生成和保存；②构造运动不但会产生大量断裂和裂缝带而增加储层的储集空间，而且会促进油气的运聚（往往与生烃期相匹配），也为古岩溶作用提供有利背景；③古岩溶等成岩作用改善了储集性能；④蒸发岩起到了良好的封盖油气作用；⑤圈闭定型时间与烃源岩的生、排烃时间需在时空上达到良好的匹配关系。

Giant carbonate stratigraphic-lithologic oil and gas field is an important type of oil and gas field in the world. It has been proved to be rich in oil and gas resources and production. Ninety-four carbonate stratigraphiclithologic oil and gas fields were theoretically analyzed, including their geographical distribution, strata distribution, trap types, buried depth and reserve scale of reservoirs,and the main controlling factors of their distribution were discussed. Such oil and gas fields are mainly distributed in the North America, Middle East and Central Asia, among which North America has the most abundant oil and gas,and the oil and gas resources of carbonate reservoirs are mainly accumulated in the Ordovician, Carboniferous, Paleogene and Neogene. The traps can be classified as biological reef, grain beach, diagenetic trap, unconformity and weathering crust. The reservoir burial depth of these oil and gas fields is generally less than 5 000 m,and the oil and gas fields with reservoir burial depth of more than 5 000 m account for only 6.4%. The effects of the following five key factors on the formation and distribution of giant carbonate stratigraphic-lithologic oil and gas fields were discussed:(1) The stable and confined shallow water environment and mid-low latitude are conducive for the generation and preservation of organic matter.(2) Tectonic movement not only increases the reservoir spaces by producing a large number of faults and fracture zones, but also promotes the migration and accumulation of hydrocarbon(usually matching with the hydrocarbon generation stage), and provides a favorable background for paleo-karstification(. 3) Diagenesis such as paleo-karst improves reservoir performance.(4) Evaporite plays an important role in sealing oil and gas.(5) Trap finalization time and hydrocarbon generation and expulsion time of source rocks need to achieve a good matching relationship in time and space.

全球已证实存在6套优质烃源岩,发育于前中生界的3套烃源岩构成了古老油气成藏组合的主要烃源岩。已发现的前中生界古老油气成藏组合有5个特点:①盆地类型以前陆盆地、被动陆缘盆地、克拉通盆地为主;②油气资源类型以常规油气为主,页岩油气发展迅速;③油气主要富集于二叠系、泥盆系、石炭系和奥陶系;④储层岩性主要为灰岩、砂岩、页岩和白云岩;⑤埋深以中—浅层为主,深层勘探潜力大。古老油气成藏组合的重大发现也具有在克拉通周缘、碳酸盐岩储层、页岩油气层系和基岩潜山4个领域富集的特征。通过对重点领域的重大发现解剖,指出长期处于低纬度热带辐合带的克拉通周缘易于形成优质生-储-盖组合;全球重大事件对烃源岩发育和页岩油气富集起着重要控制作用,可在全球重大事件时序框架下,通过重建成藏要素古位置超前优选潜在成藏组合。根据已发现油气可采储量和待发现油气资源自主评价结果,明确了常规油气资源应重点关注阿拉伯盆地、扎格罗斯盆地、塔里木盆地等;基岩潜山/残留层系也是值得重点关注的勘探领域;页岩油气应重点关注俄罗斯蒂曼—伯朝拉盆地和伏尔加—乌拉尔盆地泥盆系多玛尼克组页岩、中东地区阿拉伯盆地志留系热页岩、北非地区古达米斯盆地志留系和泥盆系、中国四川盆地和准噶尔盆地的页岩层系等领域。

Six sets of high-quality source rocks have been identified globally, with three of them in the pre-Mesozoic strata serving as the primary source rocks for ancient oil and gas reservoirs. Ancient oil and gas reservoirs from the pre-Mesozoic strata exhibit five key characteristics. (1) The predominant basin types include foreland, passive continental margin, and cratonic basins. (2) Their primary type of oil and gas resources remains conventional, although shale oil and gas is developing rapidly. (3) Their oil and gas accumulations are primarily concentrated in the Permian, Devonian, Carboniferous, and Ordovician. (4) Their reservoir lithology is primarily composed of limestones, sandstones, shales, and dolomites. (5) Their burial depth is predominantly within the middle to shallow layers, indicating significant potential for deep plays. The substantial discoveries of ancient oil and gas plays demonstrate enrichment in four fields: the periphery of cratons, carbonate reservoirs, shale oil and shale gas reservoirs, and basement reservoirs. After analyzing the major discoveries in key areas, it is revealed that high-quality source-reservoir-seal combinations form readily in the peripheral regions of cratons that were historically located within low-latitude intertropical convergence zones. Global significant events have played a crucial role in shaping the development of source rocks and the enrichment of shale oil and gas. Within the temporal framework of these significant global events, potential plays can be optimized in advance by reconstructing the paleo-positions of accumulation elements. Based on independent evaluations of recoverable oil and gas reserves and yet-to-be-discovered resources, it is evident that conventional oil and gas exploration should focus on the Arabian Basin, Zagros Basin, Tarim Basin, and other basins. Basement rocks and residual strata are also important potential exploration areas. For shale oil and shale gas exploration, the focus should be on the Devonian Domanik shale in the Timan-Pechora and the Volga-Ural basins in Russia, the Silurian hot shale in the Arabian Basin in the Middle East, the Silurian and Devonian plays in the Ghadames Basin in the North Africa, and several sets of shales in the Sichuan and Junggar basins in China.

从威尔逊旋回原理出发,通过解剖全球483个沉积盆地前寒武纪以来成盆演化历史,并基于拉张、挤压及剪切3种应力环境,探讨了原型盆地的类型划分、叠加演化及沉积充填模式,总结出板块构造演化在3个方面控制着原型盆地的叠加演化过程及含油气条件。研究认为：①全球85%以上的沉积盆地是由两类以上原型盆地叠加演化而成;②原型盆地的叠加演化过程以威尔逊旋回为周期且按着固定轨迹循环往复进行,在一个周期的每个阶段都能够形成特定的原型盆地;③每个原型盆地都能够形成独特的构造-沉积体系,从而决定其独有的生、储、盖等含油气条件,后期叠加的原型盆地不但能够改变早期原型盆地的油气成藏条件,而且可能形成新的含油气系统。将全球每个盆地最新一期板块构造运动所形成的原型盆地界定为现今的盆地类型,并划分出陆内生长裂谷、陆内夭折裂谷、陆间裂谷、被动大陆边缘、内克拉通、海沟、弧前、弧后裂谷、弧后坳陷、弧后小洋盆、周缘前陆、弧后前陆、走滑拉分和走滑挠曲共14类。该分类方案不仅能够确保每个沉积盆地类型的唯一性,便于推广应用,而且可以通过盆地类比,以科学预测现今各类沉积盆地的含油气远景。图6表1参64

Saudi Aramco is conducting an exploration program to discover additional non-associated gas reserves in the Ghawar Area. The program has successfully discovered significant sweet gas and condensate reserves in the pre-Khuff siliciclastics and has further increased our understanding of the Paleozoic petroleum system.

基于岩心、铸体薄片、测井、地震等资料,研究伊拉克哈法亚油田中白垩统Mishrif组MB1-2亚段沉积与储集层构型。Mishrif组MB1-2亚段发育潟湖相、生屑滩相和潮道相3种微相类型,沉积微相构型受层序地层约束。四级层序内,潟湖相垂向加积叠置生长,生屑滩呈透镜状镶嵌于潟湖背景中,层序沉积末期被形似“曲流河”的潮道切割,代表沉积间断面。发育潮道颗粒-泥粒灰岩储集层、生屑滩颗粒-泥粒灰岩储集层和潟湖粒泥灰岩溶蚀改造型储集层3种类型,其中潮道颗粒-泥粒灰岩储集层和生屑滩颗粒-泥粒灰岩储集层构型与沉积构型一致;潟湖粒泥灰岩溶蚀改造型储集层构型受微相构型与溶蚀改造共同控制,发育于层序界面之下。储集层段主要发育于四级层序高位域,垂向上被海侵域隔层分隔,复杂的微相构型与溶蚀改造导致储集层段表现为“阁楼式”构型特征,内部具复杂的渗流关系。研究成果对中东地区同类油藏开发具有指导意义。图9参36

针对桑托斯被动陆缘盆地深水盐下碳酸盐岩储层分布特征及大油田成藏规律不清的难题，综合利用地质、地震及岩心等数据资料，通过早白垩世原型盆地与岩相古地理恢复重建，提出盐下碳酸盐岩沉积建造受控于坳间断隆型和坳中断凸型两类孤立台地。坳间断隆型孤立台地分布于现今盐下坳间隆起带上，建造于早期陆内和陆间裂谷两个原型阶段继承性发育的单断式和双断式垒式断块上，早白垩世陆内裂谷晚期沉积的ITP组介壳灰岩和陆间裂谷早期沉积的BVE组微生物灰岩为连续建造；坳中断凸型孤立台地分布于现今盐下坳陷带中，建造于早期陆内裂谷原型阶段火山岩建隆所形成的凸起带上，发育BVE组微生物灰岩。两类孤立台地灰岩所形成礁滩体均具有储层厚度大、物性好的特点。结合盐下已发现大油田解剖，发现两类台地均可形成大型构造-岩性复合圈闭，周缘为优质湖相和潟湖相烃源岩环绕，上覆为巨厚的优质蒸发盐岩盖层高效封堵，形成了“下生中储上盖”式最佳生储盖组合关系，油气富集程度高。已发现大油田均为具有统一压力系统的底水块状油田，且均处于充满状态。未来勘探重点目标是西部隆起带和东部隆起带南段上的坳间断隆型孤立台地及中央坳陷带中的坳中断凸型孤立台地。该项研究成果为在桑托斯被动陆缘盆地超前选区选带、新项目评价及中标区块探区勘探部署提供了重要依据，也为今后在全球被动大陆边缘盆地深水勘探战略选区提供借鉴。

基于区域地质、二维地震及大洋钻探等数据,通过构造精细解释及地震相研究,分析了东地中海埃拉托色尼海山（ESM）及其周缘孤立台地形成、生物礁体类型及油气成藏条件等,指出了未来勘探方向。研究表明,东地中海ESM等系列孤立碳酸盐台地形成演化与新特提斯洋的开合休戚相关,早期为从非洲-阿拉伯板块上裂解出来的垒式断块,形成于中三叠世—早侏罗世陆内裂谷阶段,经过中侏罗世陆间裂谷阶段、晚中侏罗世—晚白垩世土伦期漂移阶段和晚白垩世森诺期—中新世俯冲消减阶段继承性碳酸盐岩沉积建造,晚中新世梅西期以来受新特提斯洋关闭影响发生中—轻度反转改造。受不同古构造背景控制形成3类孤立台地,一是小规模狭窄垒式断块所控制的单个点礁型孤立台地,二是中等规模宽缓垒式断块所控制的单个环礁型孤立台地,三是大规模宽缓古隆起控制形成的多个礁滩复合体型孤立台地。前两类在埃南和埃西凸起上普遍发育,第3类只分布于ESM海山之上。纵向上,受海平面升降影响,ESM古隆起、埃南和埃西凸起上均发育了中侏罗统巴柔阶—上白垩统土伦阶和中新统两套礁体建造。单个点礁型孤立台地和单个环礁型孤立台地已被钻井证实具有优越的天然气成藏条件,ESM海山隆起带上多个礁滩复合体型孤立台地同样值得探索。图11参42

2021年,南美桑托斯盆地深水区风险探井古拉绍-1井获得重大原油发现,地层测试获得日产千吨高产油流,确定了巴西阿拉姆区块超大型油藏的勘探潜力,证实其具有规模商业开发前景。为了更好认识这一重大突破,在区域地质背景分析的基础上,结合油气勘探历程,对古拉绍-1井的构造-沉积背景、油气成藏条件以及油藏特点进行了详细分析。研究结果表明:①阿拉姆区块位于桑托斯盆地阿拉姆—乌拉普鲁(阿—乌)隆起带,与卢拉—苏格(卢—苏)隆起带的卢拉油田隔"湖"相望,具有相似的构造沉积背景;盆地中央大型古隆起为碳酸盐岩沉积提供了有利条件。②阿拉姆区块邻近主力生烃凹陷,油源充足。③继承性古隆起控制了湖相碳酸盐岩储层连片分布。④盐岩、盐上灰泥岩和泥岩对油藏形成了多重有效封盖。⑤盐下背斜圈闭规模大,为有利油气指向区。⑥古拉绍-1井油藏属于低CO₂、低H₂S中质油超压油藏。古拉绍-1井的成功钻探是巴西桑托斯盆地盐下核心区向外围区拓展取得的重大突破,是中国石油天然气集团有限公司(中国石油)坚持海外风险勘探的重大成功,是中国石油海外深水油气合作发展的又一成功实践,对巴西桑托斯盆地盐下油气勘探工作以及中国石油深水油气业务发展战略具有指导意义。

In 2021, a great breakthrough has been made in discovery of crude oil in the risk exploration well, i.e., Well Gulashou-1, in deep water area of Santos Basin in South America; a daily production of thousands of tons of high-yield oil flows was obtained in the drill stem testing, thus determining a super large oil reservoir in the Alam block in Brazil and confirming its potential for large-scale commercial development. To better understand this major breakthrough, the tectonic-sedimentary environment, accumulation conditions and reservoir characteristics of Well Gulashao-1 were analyzed in detail based on the analysis of regional geological background, in combination with the exploration history. The results show as follows. (1) Alam block is located in the Alam-Uirapuru uplift belt of Santos Basin, facing with Lula oilfield in the Lula-Sugar uplift belt across a lake, and the both has a similar tectonic-sedimentary background. The large paleo-uplift in the center of the basin provides favorable conditions for carbonate sedimentation. (2) Alam block is adjacent to the main hydrocarbon generating sag with abundant oil sources. (3) The inherited paleo-uplift controls the contiguous distribution of lacustrine carbonate reservoirs. (4) Salt rocks, post-salt calcilutites and mudstones have formed multiple effective seals on the oil reservoir. (5) The pre-salt anticlinal trap is developed on a large scale, demonstrating a favorable migration direction of oil and gas. (6) The pool in Well Gulashao-1 is an overpressure reservoir, which produces medium crude oil with low CO₂ and H₂S contents. The successful drilling of Well Gulashao-1 is a major breakthrough of oil exploration expanding from the pre-salt core area to the periphery in Santos Basin of Brazil. It is a major success achieved by PetroChina Company Limited (PetroChina) in adhering to overseas risk exploration and also a successful practice of overseas cooperation for deepwater oil and gas exploration in PetroChina. It is of guiding significance to the pre-salt oil and gas exploration in Santos Basin of Brazil and the development strategy of deepwater oil and gas business in PetroChina.

巴西桑托斯盆地下白垩统Barra Velha组发育形状为球粒状、灌木状、树枝状的湖相碳酸盐结构组分,但对其成因的认识尚未统一。利用岩心、薄片资料,结合地球化学测试结果和区域构造背景,详细分析了Barra Velha组碳酸盐岩的结构组分特征、分类及其成因环境特征。研究表明: Barra Velha组发育十字消光的球粒状组构及波状消光的扇状、灌木状和树枝状组构,垂向上呈泥晶—球粒状—树枝状组构沉积序列; 微量元素、碳氧同位素及团簇同位素测试结果支持Barra Velha组球粒状—树枝状组构沉积时,水体具高盐度、高温的特点。结合区域沉积背景,提出深大断裂沟通热液导致湖水升温、表层海水频繁海侵补给盐类物质的桑托斯盆地球粒状—树枝状组构热水沉积模式。该研究成果可以较好地解释球粒状—树枝状组构快速生长的特征,也为该层系碳酸盐岩储层成因和分布规律研究提供了新的依据。

The Lower Cretaceous Barra Velha Formation in Santos Basin,Brazil,consists of lacustrine carbonate components with spherical,dendritic and shrub structures,but their origin has not been unified yet. Based on the analysis of drilling core and thin section data,combined with geochemical data and regional tectonic background,this paper analyzes the characteristics of various components,classification, and depositional environments of these carbonate rocks. The research shows that spherical crystals with cross extinction under orthogonal light developed in the Barra Velha Formation,also including fan-shaped crystals,dendriform crystals and dendritic crystals with undulatory extinction. The micritic limestone,spherical crystal and dendritic crystal formed an upper vertical sequence. Trace elements,carbon and oxygen isotopes,and clumped isotopes,suggest a high-salinity and high-temperature fluid condition when the spherulite-dendritic crystals were deposited. In combination with regional tectonic background of the Santos Basin,this paper proposes the spherical crystal-dendritic particles were caused by the hydrothermal fluid connected by the deep large faults,and the saline minerals charge supplied by the frequent seawater transgression. This model better explains the characteristics of the rapid growth of spherulite-dendritic particles,and provides a new theoretical basis for the genesis and distribution of carbonate reservoirs in this basin.

The Middle Ordovician strata are well deposited in the south margin of northern Tarim Basin. Drill data reveale that no long-term exposed unconformity surface exists on the Middle Ordovician strata and the karst reservoirs develop in the strata. Bordered by the pinchout line of upper Ordovician Shangtamu Fm., a burial hill area in the north and an inner area in the south can be divided. Cavernous and fractured+vuggy reservoirs are predominant in the burial hill area. Fractured+porous+vuggy reservoirs are dominant while porous+vuggy and cavernous reservoirs are also common in the inner area. Generally, the development of karst reservoirs exhibits bed-liked in lateral and focuses vertically within the interval of 100 meters below the top surface of Yijianfang Fm., whereas the reservoirs get weak in deveploping extent from north to south and distribute locally along faults. By means of the analysis of cores, thinsections, FMI, hydrologic data and geologic setting, it is shown that the Middle Ordovician karst reservoirs originate considerably from karstification taking place along rock layers. The fact that the overlying upper Ordovician mud-rich strata in the inner area prevented phreatic underground water from flowing back to the surface brings in an unstable phreatic water table under which the slow flow zone provides high potential energy for underground water to flow. It is suggested that the geological setting incluidng paleouplift and slope is the prerequisite of developing karstifiaction, and permeable grainstone and fracture system may form available pathways for diagenetic fluids. The karstification along layers advancesa variety of reservoir spaces.

北方-南帕斯气田由主要位于波斯湾海域卡塔尔境内的北方气田和伊朗境内的南帕斯气田组成，是目前世界上最大的天然气田。介绍了该气田的地质概况和天然气地球化学特征。北方-南帕斯气田处于卡塔尔穹窿的北部，为背斜圈闭类型，气层为二叠纪-早三叠世Khuff组碳酸盐蒸发岩地层，源岩为下志留统页岩，盖层为三叠纪Dashtak组。通过天然气碳同位素地球化学特征的分析，认为该气田的烷烃气主要是油型气，是同型不同源或同源不同期的油型气混合；气源岩主要是Ⅱ型干酪根，Ro在1．0％～1．5％之间；CO₂是有机成因的。

The North-South Pars gas field, which is the largest gas field in the world, is the combination of the North gas field which is located in Qatar and the South Pars gas field in Iran. This paper introduces the geological setting of the North-South Pars gas field and analyses the geochemical characteristics of the gases. The North-South Pars gas field is a part of Qatar arch, and the type of the trap is anticlinal trap. The pay zones are the Permian-Early Triassic Khuff Formation carbonate-evaporites, with the Lower Silurian organic-rich shales and Triassic Dashtak formation sediments made up the source rocks and seals, respectively. Based on the study of the carbon isotopes, we made the conclusion as follows. ① The alkane of this field mainly are oil type gas; ② There are mix of same-type different-origine or same-origine different-period; ③ The source rocks generally contain kerogen type Ⅱ with the maturity between 1.0- 1.5% ; ④ CO2 from this field is organic origin.

基于岩心、成像测井及裂缝网络建模结果，应用拓扑学理论，对滨里海盆地东缘北特鲁瓦油田石炭系碳酸盐岩储层裂缝网络的连通性进行了评价，并分析了其对油田开发的影响。研究结果表明： ①滨里海盆地东缘北特鲁瓦油田石炭系碳酸盐岩储层裂缝切割类型可划分为高高切割、高低切割和低低切割，研究区A2，A3，G1，G2，G3及G4小层裂缝切割较为发育，且主要分布在构造高部位。②裂缝网络连通性可通过连通体面积占比、裂缝体密度、裂缝的平均长度和平均节点数4个参数进行定量评价，根据连通体面积大小、裂缝体密度大小及裂缝类型可对裂缝连通体进行定性分析和命名，研究区A2小层主要发育低低大连通体、高中大连通体和高高大连通体。③裂缝网络连通性和储层物性的耦合作用是油田水窜的原因，裂缝网络连通性主要与裂缝长度和裂缝体密度有关。

Based on the data of core，imaging logging，and fracture network modeling，topology theory was applied to evaluate the connectivity of fracture networks of Carboniferous carbonate reservoirs in North Truva Oilfield，the eastern margin of Precaspian Basin，and its impacts on oilfield development were analyzed. The results show that：（1）The types of fracture cutting of Carboniferous carbonate reservoirs in North Truva Oilfield of eastern margin of Precaspian Basin can be divided into high-high cutting，high-low cutting，and low-low cutting. The fracture cutting in the sublayers A2，A3，G1，G2，G3，and G4 is relatively developed and mainly distributed in the high structural parts.（2）The connectivity of fracture networks can be quantitatively evaluated through four parameters：the proportion of connected area，fracture fracture volume density，average length of fractures，and average number of nodes. The connected area，fracture volume density，and fracture type can be used to qualitatively analyze and name the fracture connected units. The sublayer A2 in the study area mainly develops low-low large connected units，high-medium large connected units，and high-high large connected units. （3）The coupling effect of fracture network connectivity and reservoir properties is the origin of oilfield water channeling，and fracture network connectivity is mainly related to fracture length and fracture volume density.

根据三维地震、测井及钻井取心等资料,结合Vail的层序划分方案,在滨里海盆地东缘北特鲁瓦油田石炭系碳酸盐岩台地内识别出7个地震层序界面及7个钻井层序界面,并将KT-Ⅰ油层组划分为3个半三级层序,KT-Ⅱ油层组划分为3个三级层序。纵向上层序格架内沉积环境由开阔台地、局限台地至蒸发台地演化。根据研究区层序格架内的古地貌恢复及沉积演化研究,将研究区古地貌&mdash;沉积演化划分为3个阶段: 台地初始隆坳分异期(SQ2-SQ3层序)、差异抬升与沉积分异定型期(SQ4层序)及继承发育期(SQ5-SQ7层序)。进一步分析认为,层序格架控制下的隆坳格局分异控制了白云岩亚类在平面上的分布,低部位以泥晶云岩&mdash;膏盐岩组合和泥晶云岩&mdash;泥晶灰岩组合为主,主要为潟湖相沉积; 而高部位则以泥粉晶云岩、细粉晶云岩和残余颗粒泥晶云岩为主,发育云坪相及云化颗粒滩相沉积。结果表明,区内KT-Ⅰ油层组沉积期并非前人认为的西高东低剥蚀后沉降充填,而是继承性差异沉降的结果,古地理格局总体具有&ldquo;东台西槽、北高南低&rdquo;特征,其始终控制着有利相带和优质储集层的发育展布。这一认识对滨里海地区油气勘探开发战略选区具有重要的指导作用。

<p>Based on 3D seismic and borehold data,seven seismic sequence boundaries and seven drilling sequence boundaries are identified in the Carboniferous carbonate platform of North Troyes Oilfield. The KT-I reservoir group is divided into three and a half third-order sequences,and the KT-Ⅱ reservoir group is divided into three third-order sequences. The sedimentary environment evolved stratigraphically from open platform,through restricted platform,to evaporative platform. According to the palaeo-geomorphic restoration and sedimentary evolution within the sequence framework of the study area,the palaeogeomorphic and sedimentary evolution of the study area can be divided into three stages: the initial phase of differential platform uplift and depression(SQ2-SQ3 sequence),the finalizing phase of differential uplift and sedimentary differentiation fixing period(SQ4 sequence),and the inherited development phase(SQ5-SQ7 sequence). Further analysis shows that the uplift and depression pattern under the control of sequence framework controls the plan-view distribution of dolomite subclasses. The lower part of the sequences are dominated by micritic dolomite-gypsum and micritic dolomite-micritic limestone assemblages,which are characteristic of mainly lagoonal lacustrine deposits,while the higher part of the sequences are dominated by micritic dolomites,fine micritic dolomites and residual micritic dolomites.The results show that deposition of the KT-I oil formation in the study area results from inherited differential subsidence,rather than erosion and subsidence of the &ldquo;western highland and eastern lowland&rdquo;as previously thought. The overall palaeogeographical pattern is characterized by &ldquo;Platform in the east,trough in the west,high in the north and low in the south&rdquo;,which consistently controls the development and distribution of favorable facies and high-quality reservoirs. This finding is vitally important in screening for hydrocarbon exploration and production prospects in Pre-Caspian Basin.</p>

裂缝是碳酸盐岩油藏主要的渗流通道，对油田开发具有重要的影响。为揭示低角度构造缝特征及分布，进而实现有效注水开发，基于薄片、岩心和成像测井等资料，综合运用观察法和实验法分析了滨里海盆地东缘北特鲁瓦油田构造缝的发育期次，并结合构造演化历史探讨了研究区低角度构造缝成因。研究结果表明：北特鲁瓦油田共发育了3期构造缝，均以北东&mdash;南西走向为主。第1期发育于早二叠纪，以低角度构造缝为主，形成时埋深较浅，充填较早，阴极发光特征以不发光为主，古地应力的最大有效主应力为34.4MPa；第2期发育于晚二叠纪，以斜交构造缝为主，少部分被充填，阴极发光特征以昏暗发光和明亮发光为主，古地应力的最大有效主应力为42.4MPa；第3期形成于三叠纪，以高角度构造缝为主，几乎未充填，古地应力的最大有效主应力为52.2MPa。研究区低角度构造缝主要与构造演化有关，早期的高角度构造缝在地层反转后演变为低角度构造缝。通过对低角度构造缝成因的分析，为北特鲁瓦油田下一步裂缝预测及开发方案部署工作提供了指导。

针对白云岩成因、原生白云石沉淀、白云岩孔隙成因等问题,在前人认识的基础上,补充四川和塔里木盆地典型案例的岩石学和地球化学特征分析工作,取得3项进展：①提出基于岩石特征、形成环境和时间序列的白云岩成因分类,不同成因白云岩之间的成岩域、特征域界线清晰,演化线索清楚,更具系统性和连续性;②建立不同成因白云岩的岩石学和地球化学特征识别标志,白云岩之间的岩石学和地球化学特征的变化具有规律性,是连续时间序列上形成环境变迁的响应;③重新评价白云石化作用对孔隙的贡献,阐明白云岩中的孔隙主要来自原岩的沉积原生孔、部分来自表生溶蚀和埋藏溶蚀作用,早期白云石化有利于孔隙的保存。这些认识对白云岩成因的理解、不同成因白云岩的判识具重要的理论意义,同时对白云岩储集层预测具有重要的指导意义。图6表4参53

中国海相碳酸盐岩具有年代老、埋藏深、后期成岩改造强的特点,随着油气勘探逐渐走向“更老”、“更深”、“更复杂”的深层和超深层,碳酸盐岩储集层成因和分布规律成为影响油气勘探开发效益的关键因素。近年来,在塔里木、四川和鄂尔多斯三大海相盆地多个领域取得了一系列的勘探新突破,古老超深层碳酸盐岩储集层地质理论和相关技术取得显著进展。地质理论进展包括: (1)近地表环境成因孔隙构成超深层碳酸盐岩储集层的基础; (2)浅埋藏阶段的孔隙保持是决定超深层储集层质量的关键; (3)构造活动驱动深部流体运动对储集层质量具有重要改造作用。技术进展包括微量稀土元素面扫、激光U-Pb定年、团簇同位素和非传统稳定同位素等储集层地球化学实验分析技术和高温高压溶蚀模拟技术。勘探的深入和分析技术手段的进步,显著提升了对三大盆地重点领域规模优质储集层发育及分布规律的认识,为下步油田勘探取得重大突破奠定了基础。

Marine carbonate rocks in China are featured by old age,deep burial,and strongly diagenetic modification during the burial stage. As oil and gas exploration gradually extents towards “older”,“deeper”,and “more complex”deep and ultra-deep layers,the genesis and distribution patterns of carbonate reservoirs have become key factors affecting the efficiency of oil and gas exploration and development. In recent years,a series of exploration breakthroughs have been made in multiple exploration fields in the Tarim,Sichuan,and Ordos basins. Meanwhile,substantial progress has been made both in the geological theory and in the related technologies of ancient deep carbonate reservoirs. Advancements in geological theory include the following aspects: (1)porosity formecl under subaerial environment constitutes the basis of the deeply-buried carbonate reservoir size;(2)the preservation of porosity during shallow burial period is the key to the size and the quality of the deeply-buried dolomite reservoir;and(3)tectonic activity-driven deep fluid movements play an important role in modifying the quality of deeply-buried carbonate reservoir. Technological advancements include: (1)geochemically experimental analysis techniques such as surface scanning of trace rare earth elements,laser-ablation U-Pb dating,clumped isotopes and non-traditional stable isotopes;and(2)high-temperature and high-pressure dissolution simulation techniques. The deepening of exploration realm and the progress of analytical techniques have significantly improved the understanding of the development and distribution of large-scale high-quality reservoirs in deeply buried fields of the three major basins,and built the foundation for major breakthroughs in oil field exploration in the future.