阿拉斯加北坡盆地海域油气地质及勘探潜力

阿拉斯加北坡盆地海域经历了四个主要构造演化阶段,分别为前中泥盆世埃尔斯米尔造山阶段、晚泥盆世至三叠纪被动边缘阶段、侏罗纪至早白垩世裂谷阶段以及中—晚白垩世至第四纪前陆盆地阶段。研究区发育良好的生储盖组合:三叠系Shublik组为主力烃源岩;下白垩统Kuparuk组浅海相和三角洲相砂岩为主要勘探目的层,上白垩统Torok组三角洲砂岩为次要目的层;下白垩统泥岩为区域盖层,且封盖条件好。研究区在构造演化过程中形成了大量圈闭,以大型低幅背斜构造圈闭、构造-地层复合圈闭为主,并发育多套成藏组合。认为北坡盆地海域具有优越的油气成藏地质条件,待发现资源量巨大,勘探前景广阔。前陆盆地挤压构造带、楚科奇海岸、巴罗拱曲等构造圈闭发育区是有利勘探区带。     

阿拉斯加北坡盆地楚科奇海域层序格架

阿拉斯加北坡盆地经历了石炭纪—中侏罗世的被动大陆边缘阶段、中侏罗世—早白垩世的波弗特海裂谷阶段、早白垩世晚期—现今的布鲁克斯造山和前陆盆地阶段,盆山格局在古生代和现今发生了反转。盆地楚科奇海域可划分为4个一级层序与8个二级层序:4个一级层序为富兰克林巨层序、埃尔斯米尔巨层序、波弗特海裂谷巨层序、布鲁克林巨层序,层序界面分别为T_(100)、JU、K1;8个二级层序为下埃尔斯米尔超层序(SQ1)、中埃尔斯米超层序(SQ2)、上埃尔斯米尔超层序(SQ3)、下波弗特海裂谷超层序(SQ4)、上波弗特海裂谷超层序(SQ5)、下布鲁克林超层序(SQ6)、中布鲁克林超层序(SQ7)、上布鲁克林超层序(SQ8),层序界面分别为MU、PU、LCU、MAU、MBU。楚科奇海域的有利勘探区带为汉娜坳陷。     

松南地区构造-地层层序与盆地演化

松南地区地跨兴蒙-吉黑褶皱带、华北板块及其北缘增生带等大地构造单元,主要发育一系列晚中生代小规模断陷沉积盆地,这些断陷盆地具有“多阶段演化和后期强烈改造”特征,目前已在彰武、昌图、茫汉等断陷发现了油气田。如何认识这些强烈改造断陷的含油气潜力、持续拓展油气发现是目前油气勘探研究的重点,剖析其构造-地层层序,解析盆地演化历史,是深入认识地区的油气地质条件、开展油气资源预测的重要基础。本文基于研究区最新的探井和地震资料,并结合周缘1:250 000区域地质填图成果,建立研究区内的地层系统;依据区域不整合面的发育特征,划分构造-地层层序与盆地演化阶段,探讨盆地形成历史。研究认为,松南地区的沉积盆地主要是在环太平洋构造体制的控制下发育的;发育下白垩统义县组底部、下白垩统泉头组底部、上白垩统四方台组底部等3个区域性不整合面,据此划分出基底构造层、断陷构造层、坳陷构造层、盆地反转构造层等四套构造-地层层序;相应地,松南地区经历了基底形成期、早白垩世断陷期、早白垩世末-晚白垩世坳陷期、晚白垩世末盆地反转期等四个盆地演化阶段;松南地区构造演化控制了区内含油气系统的发育与油气分布规律,下白垩统断陷构造层是目前勘探的主要目的层,油气地质条件优越,具有较好的油气勘探前景。     

西非中南段盐盆成藏组合及油气勘探方向

以板块构造理论和石油地质学理论为基础,分析西非中南段盐盆形成演化、成藏组合特征,提出中南段盐盆油气勘探方向。西非中南段盐盆的形成演化可以分为前裂谷、同裂谷、过渡和后裂谷4个阶段。受盆地形成演化的控制,中南段盐盆总体发育盐下下白垩统、盐上下白垩统、上白垩统和第三系共4套储盖组合。以储盖组合为核心,根据成藏组合划分原则,在中南段盐盆5个盆地共划分出16套成藏组合。综合分析各盆地勘探现状、油气地质条件和勘探潜力后,提出中南段盐盆未来勘探以深水区勘探为主,其中下刚果盆地和杜阿拉盆地应重点关注第三系成藏组合,加蓬盆地应重点关注盐上上白垩统成藏组合和盐下下白垩统成藏组合,宽扎盆地应重点关注盐下下白垩统成藏组合,里奥穆尼盆地应重点关注上白垩统成藏组合。     

西非海岸盆地群形成演化及深水油气田发育特征

西非海岸盆地群的形成演化受非洲板块构造演化和大西洋张裂的控制,总体上可以分为前裂谷阶段、裂谷阶段和后裂谷阶段。沿岸15个主要盆地从北往南可细分为5段,分别为北段盐盆、中段盆地、尼日尔三角洲、中南段盐盆、南段盆地。深水油气田主要发育于后裂谷阶段的上白垩统和第三系海退层序中,以油田为主。在尼日尔三角洲和中南段盐盆的下刚果盆地,所发现的油气田个数及可采储量均比较集中,个数占西非深水油气田总个数比例分别为55%和29%,占总可采储量的比例分别为48%和41%。烃源岩主要有裂谷阶段下白垩统的湖相烃源岩,后裂谷阶段上白垩统、第三系的海相烃源岩。绝大多数储层为浊积岩储层,类型以深水水道砂岩为主,其次为席状砂储层和砂质碎屑流储层。圈闭类型主要为构造-地层复合圈闭,其次为构造圈闭,另外还有地层-岩性圈闭,其所占比例较小。盐构造和泥岩塑性变形构造总体上控制了西非深水区大多数复合圈闭和构造圈闭的形成。     

黔南桂中地区二叠纪—中三叠世沉积充填特征及演化过程

对野外露头、钻井剖面进行了层序界面识别和层序地层分析,重新厘定了研究区二叠系—中三叠统不同相区的地层划分对比方案,将研究区二叠系—中三叠统划分出2个超层序和19个三级层序;以超层序体系域为编图单元,编制了研究区二叠纪—中三叠世层序岩相古地理图,系统揭示了研究区二叠纪—中三叠世各超层序的不同体系域的相带发育规律;分析了研究区二叠纪—中三叠世3个盆地演化阶段(被动陆缘裂谷盆地阶段、弧后裂谷盆地阶段、前陆盆地阶段)的盆地充填特征,并建立了相对海平面升降过程中的沉积充填过程及动态演化模式,提出了研究区被动陆缘裂谷盆地阶段和弧后裂谷盆地阶段的低位期为盆-隆相间期,海侵期为台-盆相间的建设期,高位期为台-盆相间格局定型期,中三叠世的受印支运动破坏了台-盆相间格局,转化为前陆盆地的浊积岩沉积。     

西藏珠穆朗玛峰北坡地区显生宙沉积演化

位于印度板块北缘和雅鲁藏布江结合带之间的珠穆朗玛峰北坡地区，属于喜马拉雅造山带，是特提斯洋的重要组成部分。自奥陶纪至古近纪约5亿年期间发育一套基本连续的海相沉积，厚度达14 km，是研究特提斯洋形成演化的最佳地区。作者在对该区显生宙地层主干剖面和辅助剖面详细观察研究以及区域地质调查填图的基础上，将珠穆朗玛峰北坡地区显生宙沉积地层划分为海相、海陆过渡相和陆相3个沉积相组、15个沉积相和若干个沉积亚相。作者通过对该区沉积盆地的地层系统、沉积相、沉积特征的系统研究，将珠穆朗玛峰北坡地区显生宙沉积演化划分为6个阶段:1)奥陶纪-泥盆纪为稳定陆表海演化阶段；2)石炭纪-二叠纪为大陆裂谷盆地演化阶段；3)三叠纪-侏罗纪为被动大陆边缘盆地演化阶段；4)早中白垩世为前陆早期复理石盆地演化阶段；5)晚白垩世-古新世为前陆晚期磨拉石盆地演化阶段；6)古近纪-第四纪为造山隆升断陷盆地形成演化阶段。研究结果表明，珠穆朗玛峰北坡地区显生宙沉积盆地经历了由陆表海盆地-大陆裂谷盆地-被动大陆边缘盆地-前陆盆地-断陷盆地的演化过程。     

非洲地区盆地演化与油气分布

非洲地区盆地整体勘探程度较低,待发现资源量大,是当前油气勘探开发的热点地区之一。非洲板块在显生宙主要经历了冈瓦纳大陆形成、整体运动和裂解3个构造演化阶段,形成多种不同类型的盆地。通过板块构造演化和原型盆地研究及石油地质综合分析,明确了不同类型盆地的构造特征与油气富集规律。北非克拉通边缘盆地形成于古生代早期,受海西运动影响,油气主要富集在挤压背景下形成的大型穹隆构造之中,以古生界含油气系统为主;北非边缘裂谷盆地海西运动之后普遍经历了裂谷和沉降,裂谷期各盆地沉降幅度和沉降中心的差异导致了油气成藏模式和资源潜力的差异;东、西非被动陆缘盆地形成于中生代潘吉亚大陆的解体、大西洋和印度洋张裂的过程中,西非被动陆缘盆地普遍发育含盐地层,形成盐上和盐下两套含油气系统,东非被动陆缘盆地结构差异较大,油气分布主要受盆地结构控制;中西非裂谷系是经历早白垩世、晚白垩世和古近纪3期裂谷作用而形成的陆内裂谷盆地,受晚白垩世非洲板块与欧亚板块碰撞的影响,近东西向展布盆地抬升剧烈,油气主要富集在下白垩统,北西南东向盆地受影响较弱,油气主要富集在上白垩统和古近系之中;新生代东非裂谷系盆地和红海盆地形成时间相对较晚,以新生界含油气系统为主,新生代三角洲盆地中油气分布主要受三角洲砂(扇)体展布和盆地结构所控制。     

典型被动大陆边缘深水盆地构造演化与层序地层学分析

深水油气勘探是当前全球油气勘探的热点和最具发展潜力的新领域,研究被动大陆边缘深水盆地的构造演化过程和层序地层学特征无疑具有重要的理论和实践意义。通过对典型被动大陆边缘深水盆地的综合研究,分析了被动大陆边缘深水盆地的构造演化过程和层序地层学特征,认为被动大陆边缘深水盆地“经历了四大区域构造演化阶段（大陆开裂、大陆裂谷、新生大陆边缘、成熟大陆边缘）,相应发育三个不整合（裂开不整合、分离不整合和陆裾转换不整合）,可划分为四大构造层序（大陆开裂层序、大陆裂谷层序、新生大陆边缘层序和成熟大陆边缘层序）”。     

松辽盆地层序地层特征及油气聚集规律

根据野外露头、钻井岩心、测井和地震资料,建立松辽盆地各级层序的识别标志和层序地层格架,将松辽盆地地层划分为白垩纪裂谷盆地巨层序和第三纪裂谷盆地巨层序,并将白垩纪裂谷盆地巨层序进一步划分为3个超层序组,7个超层序和19个层序.松辽盆地构造演化经历了断陷期、坳陷期和萎缩期3个阶段,断陷湖盆与坳陷湖盆成因机制不同.因此,层序地层内部特征及充填序列有较大差别.通过对层序地层格架内各体系域生储盖层发育特征、组合规律和油气聚集规律研究认为:水退体系域是储集砂体最发育、油气资源量最多的层段,其次为低水位和水进体系域,高水位体系域含油气较差.     

A facies and palaeogeography-based approach for analysis of petroleum systems in United Arab Emirates

The United Arab Emirates(UAE) is the 8 th largest oil producing country and is rich in oil and gas resources. By the end of 2015, 68 oil and 23 gas fields had been discovered. The initial proved and probable(2 P) oil, gas and condensate reserves amount to 81,135.9 MMb(million barrels), 192.09 Tcf(trillion cubic feet),and 6496.58 MMb respectively, which are mostly reservoired in the Jurassic and Cretaceous carbonates. With the latest field data, this study attempts to document the salient features of petroleum systems in UAE. Based on depositional facies of source rock intervals, pods of source rocks were delineated. On the basis of an oiland gas-source correlation, five known petroleum systems were identified and they are Lower Silurian-Upper Permian Khuff gas, northeast foreland Upper Jurassic-Lower Cretaceous gas, Upper Jurassic-Jurassic petroleum, Upper Jurassic/Lower Cretaceous-Lower Cretaceous composite petroleum, and Middle Cretaceous-Middle to Upper Cretaceous/Cenozoic petroleum systems. Of them, the Upper Jurassic/Lower Cretaceous-Lower Cretaceous composite petroleum system contains 73.2% of the total 2 P reserves and thus it is the focus of this study. The Upper Jurassic and Lower Cretaceous source rocks consist of argillaceous limestone, mudstone and shale, which were deposited as intrashelf basin facies. The distribution of oil and gas in this system is controlled by the source kitchens and the regional evaporite seal.     

Contribution to study of evolution of the folding process within the tectonic cycle

Afghanistan consists largely of a series of continental fragments that, moving northward, docked and accreted to the southern proto-Asia continent. The tectonization of the accreted terranes is generally severe and petroleum prospects are limited essentially to the 48,000 mi² (124,000 km²) North Afghanistan basin. This basin represents the Afghan portion of the Turanian platform, plus the orogenic belt around its southern and eastern perimeter. Exploration to date is judged to be preliminary in character, with some 5 trillion cubic feet (TCF) of gas and 80 million barrels of oil being discovered by 1980. There are two types of traps: Mesozoic low-amplitude drapes or tilted fault blocks, and Neogene highamplitude folds. Appreciable reservoirs are limited to three horizons—Upper Jurassic, Lower Cretaceous, and Paleogene—of which the Lower Cretaceous is considered to be the best. Source rock is confined largely to the Lower and Middle Jurassic shales. Upper Jurassic evaporites form a barrier between the Jurassic source shales and the Lower Cretaceous reservoirs and Neogene folds. There appear to be five principal plays, and estimated total recoverable petroleum in them is 300 million barrels of oil, 9.6 TCF of gas, and 145 million barrels of condensate.     

全球重油与油砂资源潜力、分布与勘探方向

基于对全球主要地质时期构造、沉积演化、盆地类型和主要成藏期的地质研究,评价全球重油和油砂资源潜力,进而指出有利勘探方向.据CNPC(2011)评价结果:全球重油地质资源量为42 712亿桶,可采资源量为7 147亿桶,油砂地质资源量为66 945亿桶,可采资源量为7 095亿桶;主要分布在北美、南美、俄罗斯和高加索地区,产区集中于北美和南美.以构造域进行划分,全球重油和油砂主要富集在科迪勒拉褶皱造山带、喜马拉雅阿尔卑斯褶皱造山带、西伯利亚地台周缘山系和乌拉尔山前四个大型构造带,盆地类型以克拉通和前陆为主,以斜坡降解、抬升破坏型两种模式成藏.未来重油和油砂勘探主要集中在3类地区:1)资源落实程度较高、勘探程度高的美洲地区;2)资源潜力大、勘探程度低的俄罗斯东西伯利亚盆地、伏尔加乌拉尔盆地;3)资源潜力大、尚未引起注意的中东地区.     

南美玻利维亚重点盆地油气地质特征和勘探潜力评价

基于对玻利维亚区域构造演化与沉积充填特征的分析,研究盆地烃源岩、储集层及盖层等油气成藏地质条件的差异,分析盆地勘探潜力。玻利维亚境内发育查科、贝尼和马德雷德迪奥斯等3个重点盆地,均是在前寒武系基底基础上发育起来的叠合盆地,盆内依次充填了古生代克拉通边缘海相沉积层序、三叠纪-白垩纪裂谷期海相-海陆过渡沉积层序和晚白垩世至今前陆陆相沉积层序。油气成藏地质条件综合对比分析认为,3个盆地均发育泥盆系主力烃源岩,储集层以泥盆系-石炭系和白垩系砂岩为主,发育古生界泥岩和碳酸盐岩及古近系泥岩等多套区域盖层。成熟烃源岩主要分布在冲断带和前渊区,油气必须通过垂向和侧向运移才能聚集成藏,具有晚期生烃、晚期成藏的特点。马德雷德迪奥斯盆地前渊-斜坡带低幅构造圈闭和地层圈闭、查科盆地和贝尼盆地逆冲褶皱带构造圈闭是主要的勘探目标。     

Undiscovered Petroleum of the Brazilian Interior Rift Basins

Brazil is estimated to contain 52% of the undiscovered oil and gas resources of South America, outside of Venezuela and Colombia. The Reconcavo, Tucano-Jatoba, and Tacutu interior rift basins of Brazil are investigated in this paper, the first in a series dealing with undiscovered petroleum of South America (exclusive of Venezuela and Colombia). Preliminary estimates of the undiscovered petroleum resources are 0.273 billion barrels of oil (BBO) and 1.234 trillion cubic feet of gas (TCFG) for the four basins. A review of the 1983-1993 history of petroleum reserves in South America indicated that an initial consensus estimate of 0.27 BBO and 4.15 TCFG (mean values) by the World Energy Program Group at the U.S. Geological Survey is too low. An adjusted range of probabilities is recalculated from original identified reserves, resulting in revised mean values of 0.29 BBO and 4.15 TCFG for the four interior rift basins. Of these four basins, the Reconcavo is in a mature stage of exploration with 80 fields; the other rift basins, as well as most of the other basins in Brazil, have not been as extensively investigated. In the Reconcavo basin, the principal plays are found in the pre-rift fault blocks, and in lower Cretaceous turbidites and sand lenses. Three gas fields are known in the southern Tucano subbasin. The three subbasins (southern, central, and northern) and the adjacent Jatoba basin become progressively less prospective northward because of lower levels of source-rock maturation. The plays in these basins are similar to those of the Reconcavo. The main play in the small Tacutu basin of northwestern Brazil is in deltaic sandstones; fractured basement rocks and volcanics constitute a minor play. The best reservoirs may be expected on the margins of the basin, although the reservoir seals are absent or poorly developed.     

裂谷作用对层序地层充填样式的控制——以西非裂谷系Termit盆地下白垩统为例

Termit盆地位于尼日尔东南部,属于西非裂谷系的北延部分,是发育于前寒武系—侏罗系基底之上的中、新生代裂谷盆地。该盆地早白垩世—古近纪经历了"裂谷—坳陷—裂谷"的构造演化过程及"陆相—海相—陆相"的沉积演化过程,表现为晚白垩世大规模海侵、早白垩世和古近纪两期裂谷叠置的特点。基于构造作用影响裂谷盆地层序发育的观点,分析了Termit盆地下白垩统裂谷阶段内的层序地层充填样式。根据裂谷作用的强弱,将早白垩世裂谷阶段划分为裂谷初始期、裂谷深陷期及裂谷萎缩期3个阶段。裂谷初始期层序断裂活动弱,构造沉降小,长轴物源体系较为发育,陡坡带为加积至退积型河流或三角洲沉积,缓坡带发育加积型河流或三角洲体系。裂谷深陷期层序断裂活动强烈,构造沉降大,陡坡带形成退积型水下扇或滑塌扇沉积,缓坡带发育退积型三角洲体系,盆地中心为泥岩充填。裂谷萎缩期层序断裂活动减弱并趋于停止,陡坡带为进积型扇三角洲沉积,缓坡带发育进积型三角洲体系。研究表明:裂谷作用对层序地层充填样式具有明显的控制作用,以构造作用为主线的裂谷盆地层序地层分析方法,能有效预测沉积体系和储层分布。     

Characteristics of Hydrocarbon Fluid Inclusions and Their Significance for Evolution of Petroleum Systems in the Dabashan Foreland, Central China

Field investigation combined with detailed petrographic observation indicate that abundant oil,gas,and solid bitumen inclusions were entrapped in veins and cements of sedimentary rocks in the Dabashan foreland,which were used to reconstruct the oil and gas migration history in the context of tectonic evolution.Three stages of veins were recognized and related to the collision between the North China block and the Yangtze block during the Indosinian orogeny from Late Triassic to Early Jurassic(Dl),the southwest thrusting of the Qinling orogenic belt towards the Sichuan basin during the Yanshanian orogeny from Late Jurassic to Early Cretaceous(D2),and extensional tectonics during Late Cretaceous to Paleogene(D3),respectively.The occurrences of hydrocarbon inclusions in these veins and their homogenization temperatures suggest that oil was generated in the early stage of tectonic evolution,and gas was generated later,whereas solid bitumen was the result of pyrolysis of previously accumulated hydrocarbons.Three stages of hydrocarbon fluid inclusions were also identified in cements of carbonates and sandstones of gas beds in the Dabashan foreland belt and the Dabashan foreland depression(northeastern Sichuan basin),which recorded oil/gas formation,migration,accumulation and destruction of paleo-reservoirs during the D2.Isotopic analysis of hydrocarbon fluid inclusions contained in vein minerals shows that δ~(13)C_1 of gas in fluid inclusions ranges from-17.0‰ to-30.4‰(PDB) and δD from-107.7‰ to-156.7‰(SMOW),which indicates that the gas captured in the veins was migrated natural gas which may be correlated with gas from the gas-fields in northern Sichuan basin.Organic geochemical comparison between bitumen and potential source rocks indicates that the Lower Cambrian black shale and the Lower Permian black limestone were the most possible source rocks of the bitumen.Combined with tectonic evolution history of the Dabashan foreland,the results of this study suggest that oil was generated from the Paleozoic source rocks in the Dabashan area under normal burial thermal conditions before Indosinian tectonics and accumulated to form paleo-reservoirs during Indosinian collision between the North China block and the Yangtz block.The paleo-reservoirs were destroyed during the Yanshanian tectonic movement when the Dabashan foreland was formed.At the same time,oil in the paleo-reservoirs in the Dabashan foreland depression was pyrolyzed to transform to dry gas and the residues became solid bitumen.     

东尼日尔Termit盆地叠置裂谷的演化:来自构造和沉积充填的制约

东尼日尔Termit盆地是中西非裂谷系中典型的中—新生代裂谷盆地。在充分应用钻井和地震解释资料的基础上,根据构造、沉积充填及主要区域性不整合面的特征,分析了该盆地的演化过程。盆地内主要发育两类断层,第一类断层形成于早白垩世,于古近纪发生继承性活动,第二类断层为形成于古近纪的新生断层。全盆地普遍存在4个主要区域性不整合面,分别位于下白垩统、上白垩统、古近系、新近系—第四系底部。下白垩统和古近系沉积特征受断层活动控制明显,上白垩统和新近系沉积中心位于盆地中部,在其沉积时构造活动较弱。构造和沉积充填特征表明,Termit盆地经历了白垩纪和古近纪—第四纪两期裂谷旋回叠置的演化过程。下白垩统和古近系沉积于同裂谷期,沉积充填受断层活动控制;上白垩统和新近系—第四系沉积于后裂谷期,以热沉降拗陷作用为主。     

下刚果-刚果扇盆地沉积-构造演化与油气勘探领域

摘要：下刚果-刚果扇盆地位于西非海岸,因其富含油气,资源潜力大,长期以来一直引起众多研究者的关注。由于该区盐构造发育,变形复杂,盆地不同地区和不同勘探目的层勘探程度并不均衡,如何全面认识和评价盆地油气资源潜力成为指导下步勘探工作的关键。通过盆地沉积-构造演化特征研究,指出下刚果-刚果扇盆地是由下刚果盆地与刚果扇盆地垂向上叠置、平面上复合所形成的叠合复合型含油气盆地,经历了前裂谷期、陆内裂谷期、陆间裂谷期和被动陆缘期等演化阶段;在构造特征分析基础上,综合考虑油气成藏要素和运聚方式等特点,划分出新生界构造-岩性圈闭、盐上白垩系构造圈闭和盐下白垩系等三个油气勘探领域;通过各勘探领域油气成藏特征等的系统分析,指出了盆地东部陆上-浅水地区是勘探盐上白垩系构造圈闭勘探领域和盐下白垩系勘探领域的有利地区,盆地西部深水-超深水地区是勘探新生界构造-岩性圈闭勘探领域的有利地区。