澳大利亚北卡那封盆地中上三叠统Mungaroo三角洲陆源有机质分布特征

北卡那封盆地中上三叠统Mungaroo组发育巨型浅水辫状河三角洲——Mungaroo三角洲。利用钻井、岩心资料,并结合区域地质背景,将Mungaroo三角洲划分为近端三角洲平原、远端三角洲平原、三角洲前缘、前三角洲4个沉积亚相,其中近端三角洲平原与远端三角洲平原亚相分布广泛,三角洲前缘与前三角洲亚相欠发育。陆源有机质分析表明:(1)研究区目的层段沉积时期,在环特提斯洋巨型季风洪水的影响下,泥炭沼泽普遍遭受冲刷改造,有机质类型主要为分散有机质,仅远端三角洲平原发育薄煤层;(2)不同相带受季风洪水的影响差异较大,近端三角洲平原受洪水改造强烈,砂砾岩发育,夹薄层泥岩,泥岩中有机质显微组分主要为惰质组,镜质组大部分遭受氧化;(3)远端三角洲平原的沼泽沉积尽管受到洪水频繁冲刷,但仍发育多套薄煤层,泥岩中陆源有机质最为丰富,显微组分以镜质组为主;(4)三角洲前缘和前三角洲相带窄,沉积物中陆源有机质含量较低。远端三角洲平原烃源岩有机质生烃潜力最大,除发育广泛的薄煤层外,暗色泥岩中平均TOC含量可达4.11％。上述沉积相带与陆源有机质分布规律体现了强季风洪水影响下大型辫状河三角洲的沉积特点。     

The Mesozoic structural evolution of the Gorgon Platform,North Carnarvon Basin,Australia

The Gorgon Platform is located on the southeastern edge of the Exmouth Plateau in the North Carnarvon Basin, North West Shelf, Australia. A structural analysis using three-dimensional (3D) seismic data has revealed four major sets of extensional faults, namely, (1) the Exmouth Plateau extensional fault system, (2) the basin bounding fault system (Exmouth Plateau–Gorgon Platform Boundary Fault), (3) an intra-rift fault system in the graben between the Exmouth Plateau and the Gorgon Platform and (4) an intra-rift fault system within the graben between the Exmouth Plateau and the Exmouth Sub-basin. Fault throw-length analyses imply that the initial fault segments, which formed the Exmouth Plateau–Gorgon Platform Boundary Fault (EG Boundary Fault), were subsequently connected vertically and laterally by both soft- and hard-linked structures. These major extensional fault systems were controlled by three different extensional events during the Early and Middle Jurassic, Late Jurassic and Early Cretaceous, and illustrate the strong role of structural inheritance in determining fault orientation and linkage. The Lower and Middle Jurassic and Upper Jurassic to Lower Cretaceous syn-kinematic sequences are separated by unconformities.     

A fine balance: Accommodation dominated control of contemporaneous cool-carbonate shelf-edge clinoforms and tropical reef-margin trajectories,North Carnarvon Basin,Northwestern Australia

The concurrent development of a cool-carbonate Miocene clinoform system and the tropical reef which developed on its shelf in the North Carnarvon Basin is studied. The study, based on seismic interpretation and geometrical analysis, seeks to investigate how the architecture of the clinoforms develops in relation to the advance of the reef-margin, providing a proxy for discussing contemporaneous shoreline versus shelf-edge development. The progradation of the reef and shelf-edge often display a closely mirrored development, although the reef twice advances an order of two to three times the concurrent advance of the shelf-edge. The forced regression of the second advance, as compared to the normal regression during the first, is observed in proportionally higher input of sediment towards advance of the shelf-edge and toe, along with a gentler slope. The inability of the shelf-edge to keep pace with the reef-margin (and by proxy the shoreline) during lower accommodation/sedimentation is a result of the increased volume of sediment required to match reef-margin advance beyond the shelf-edge. Increased accommodation/sedimentation ratios promote higher trajectories where the volumes on shelf and slope are more balanced and the development more closely matched. The observed matched development of reef and shelf-edge during both limited and increased slope sedimentation, suggest that accommodation is the dominant control on the location and trajectory of both ‘shoreline’ and shelf-edge, and that excess sediment is deposited along the slope.     

Rheological controls on extensional styles and the structural evolution of the Northern Carnarvon Basin,North West Shelf,Australia

The extensional architecture of the Northern Carnarvon Basin can be explained in terms of changes in lithospheric rheology during multiphase extension and lower crustal flow. Low‐angle detachments, while playing a minor role, are not considered to have been the primary mechanism for extension as suggested in previous models. Early extension (Cambrian‐Ordovician) in the Northern Carnarvon Basin is characterised by low‐angle detachment structures of limited regional extent. These structures have a spatial association with a Proterozoic mobile belt on the margin of the Pilbara Craton. Thermo‐mechanical conditions in the mobile belt may have predisposed the highly deformed crust to thin‐skinned extension and detachment development. Permo‐Carboniferous extension generated an extensive wide rift basin, suggesting ductile rheologies associated with intermediate lithospheric temperatures and crustal thickness. Thick Upper Permian to Upper Triassic post‐rift sequences and marked thinning of the lower crust occurred in association with only a small amount of extension in the upper crust. This observation can be reconciled by considering outward lower crustal flow, from beneath the basin towards the basin margin, following extension. Strong mid‐crustal reflectors, which occur over large areas of the Northern Carnarvon Basin, probably represent a boundary between flow and non‐flow regimes rather than detachment fault surfaces as in previous models. Crustal thinning and thermal decay following Permo‐Carboniferous extension contributed to the increased strength and brittle behaviour of the lithosphere. Consequently, Late Triassic to Early Cretaceous extension resulted in the development of far more localised narrow rift systems on the margins of the preceding wide rift basin. Diapiric intrusions are associated with the narrow rift basin development, resulting from either remobilisation of ductile lower crustal rock or the initial formation of sea‐floor spreading centres.     

南海北部深水区油气勘探的关键地质问题

南海北部深水区已经获得了重大的天然气发现,正逐渐成为全球深水勘探的热点区之一。通过与相邻陆架区以及世界上典型深水盆地的类比发现,南海北部深水区具有独特的石油地质特征。南海北部大陆边缘经历了从燕山期主动陆缘向新生代边缘海被动陆缘的转变,其演化过程和成盆机制复杂;陆坡深水区具“热盆”特征,凹陷普遍发育超压,其生烃机制不明;深水区距离物源区较远,缺乏世界级大河系的注入,具远源沉积特征,未发现盐层及其相关构造,其油气成藏条件具有特殊性。此外,南海北部深水区海底地形崎岖、多火山,还面临着地震采集、处理等地球物理难题。因此,南海北部深水油气勘探需要在借鉴相邻陆架区和世界其他深水区成功经验的基础上,一方面深入研究其独特的油气地质特征,另一方面研发适应于我国深水环境的地球物理新技术,切实推动深水勘探的进程。     

南苏门达腊盆地油气地质特征与勘探潜力分析

以广泛收集的数据资料为依据,运用含油气盆地理论方法,总结南苏门达腊盆地构造沉积演化和油气地质特征,探讨油气分布规律,分析其勘探潜力。结果显示,南苏门达腊盆地是新生代弧后裂谷盆地,经历了裂前、裂谷、过渡、坳陷和反转等5个演化阶段。主力烃源岩为过渡期沉积的炭质页岩和煤层,储集层主要为上渐新统砂岩、下中新统灰岩和裂缝基底。油气总体呈现"深层气、中层油和气、浅层油"的分布特征,主要富集于构造及构造复合相关圈闭中。断裂、储层发育有利相带和凹中隆是控制油气分布的主要因素。盆地油气成藏条件良好,具有较好的勘探潜力。生烃灶周边断裂发育的斜坡、古隆起是有利的勘探区,凹陷内的岩性、地层圈闭也是有利的勘探目标,应加大对此类圈闭的研究和勘探力度。     

宁夏六盘山盆地白垩系马东山组页岩气地质特征与勘探潜力分析

以六盘山盆地固页1井白垩系马东山组泥页岩为研究对象,通过野外观察、岩心编录、岩石热解、X衍射、干酪根元素分析、等温吸附等手段,对六盘山盆地固页1井白垩系马东山组页岩气勘探潜力进行评价。结果表明:(1)六盘山盆地白垩系马东山组具有丰富的荧光、油迹、沥青等油气显示,并见200余米的暗色泥页岩、油页岩层位。(2)马东山组泥页岩有机质类型为Ⅱ～Ⅲ型;65%样品TOC大于1.0%,37.2%的样品TOC大于2.0%;50%样品Ro大于0.8%,T_(max)处于435～445℃,处于低成熟—成熟阶段,属生物成因气与热成因气混合气。(3)马东山组泥页岩具黏土矿物低,长石类和碳酸盐类矿物含量高的特征,碳酸盐类矿物均值达38.2%,长石类含量均值24.4%,石英含量均值17.2%,黏土含量均值仅为13.2%;符合页岩气压裂施工的黏土含量小于30%,脆性矿物含量大于40%标准。其黏土组成以伊利石和伊/蒙间层为主,均值含量分别达69%、26.1%。(4)马东山组泥页岩有效孔隙度介于0.117%～1.268%;渗透率0.0009～0.0042 m D,属低孔低渗储层。马东山组泥页岩具有较强的储气能力,其最大甲烷吸附能力介于0.96～4.6 m~3/t,均值2.29 m~3/t。(5)对比延安组页岩地质、地化参数,认为六盘山盆地白垩系马东山组泥页岩层位具备较好的页岩气勘探潜力,可以作为良好的页岩气层位进行进一步工作,其成果将对河西走廊白垩系非常规油气层位勘探具有借鉴意义。     

鄂尔多斯盆地西缘横山堡地区构造特征与油气勘探目标优选

鄂尔多斯盆地西缘北区横山堡地区是重要的油气接替区域。本文利用构造解析、地震勘探等技术方法,对研究区构造特征与油气勘探目标进行了研究。结果表明,晚侏罗纪末期,研究区为银川复背斜东翼,喜山期构造调整后转为前缘反冲带,由一系列西冲东倾逆冲断层与断背斜组成;该区可分为西部逆冲断褶带、中部逆冲断阶带和东部过渡构造带3个构造单元。断层可分为4级;以燕山期近南北—北北东向逆断层为主,其次为喜山期近东西向走滑断层,并错断了燕山期逆断层。构造样式为一系列东倾单向叠瓦状冲断组合,由近南北向逆断层及加持于其中的断块组成,断块往往为一些小型断背斜,其轴迹走向以近南北—北北东向为主。地质结构为深层滑脱型单向东倾冲断构造。根据上述研究,在沙亥庙断裂上盘断背斜构造高部位优选出一个钻探目标。     

苏北盆地油气富集与分布的主控因素

根据烃源岩及沉积体系的分布、断裂的发育与分布、盖层的发育状况、圈闭形成时期等因素与油气富集特征的分析,认为苏北盆地各凹陷的油气富集程度与其烃源岩的发育程度有关,油气藏的形成及分布与断层密切相关,断层是控制油气成藏与富集的主要因素之一;紧邻生烃中心的长期隆起区是油气运移的指向区,控制油气的聚集成藏;区域盖层阻止油气往上覆层运移,其下伏储集层段为油气富集层段,缺乏统一区域性盖层的层段,局部盖层发育与否直接影响油气富集程度;沉积体系的分布控制油气的分布和富集地区。     

Evaluation of the oil and gas preservation conditions,source rocks,and hydrocarbon-generating potential of the Qiangtang Basin: New evidence from the scientific drilling project

The Qiangtang Basin of the Tibetan Plateau, located in the eastern Tethys tectonic domain, is the largest new marine petroliferous region for exploration in China. The scientific drilling project consisting primarily of well QK-1 and its supporting shallow boreholes for geological surveys (also referred to as the Project) completed in recent years contributes to a series of new discoveries and insights into the oil and gas preservation conditions and source rock evaluation of the Qiangtang Basin. These findings differ from previous views that the Qiangtang Basin has poor oil and gas preservation conditions and lacks high-quality source rocks. As revealed by well QK-1 and its supporting shallow boreholes in the Project, the Qiangtang Basin hosts two sets of high-quality regional seals, namely an anhydrite layer in the Quemo Co Formation and the gypsum-bearing mudstones in the Xiali Formation. Moreover, the Qiangtang Basin has favorable oil and gas preservation conditions, as verified by the comprehensive study of the sealing capacity of seals, basin structure, tectonic uplift, magmatic activity, and groundwater motion. Furthermore, the shallow boreholes have also revealed that the Qiangtang Basin has high-quality hydrocarbon source rocks in the Upper Triassic Bagong Formation, which are thick and widely distributed according to the geological and geophysical data. In addition, the petroleum geological conditions, such as the type, abundance, and thermal evolution of organic matter, indicate that the Qiangtang Basin has great hydrocarbon-generating potential.©2023 China Geology Editorial Office.     

准噶尔盆地东部石炭系火山岩气藏石油地质特征及有利勘探方向分析

准噶尔盆地火山岩油气勘探取得重大进展。笔者经综合研究,提出影响该区天然气藏形成的石油地质主要特征是：前陆坳陷控制了烃源岩区域展布,后碰撞火山岩是主要的储层,古生代晚期的构造优化了储层物性并形成圈闭。松喀尔苏组为前陆坳陷磨拉石建造的近端粗碎屑岩沉积,是克拉美丽造山事件后快速沉积产物,作为主要烃源岩的下石炭统滴水泉组,是与松喀尔苏组同期前陆坳陷不同位置的沉积层系,滴水泉组是前陆坳陷中央的细粒沉积层系。后碰撞火山岩覆盖在前陆坳陷沉积层系之上,分布广泛,分布范围不受古生代造山带和现今构造单元控制。二叠纪发育断陷构造,形成凹隆相间的构造格局,在构造高部位的隆起区石炭系火山岩风化壳和构造裂缝,优化改善了火山岩储层的储集性能,形成有利油气运移通道和储集空间。克拉美丽山南缘的前陆坳陷中央为有利烃源岩分布区,该范围内的构造高部位的火山岩发育区,将是准噶尔盆地东部下一步火山岩油气藏勘探的有利区域。     

化探技术在塔里木盆地和准噶尔盆地油气勘探中的应用

中国西部塔里木盆地、准噶尔盆地油气资源丰富,是重要的油气能源基地,也是广泛应用化探技术于油气勘探过程的地区。总结这些地区油气化探的应用效果和成功案例,对现阶段西北地区的油气勘探具有重要的作用和意义。近20年,塔里木盆地、准噶尔盆地陆续取得的油气化探成果,随着两大盆地油气资源的逐步发现,越来越多地得到验证。不仅表明油气勘探中运用化探技术可以带来勘探效益的提高,更证明了在现今勘探难度增大、勘探成本居高不下的形势下,综合勘探技术的成功应用可以缩短勘探周期,提高勘探成功率。     

墨西哥Sureste盆地Salina次盆石油地质特征与勘探方向

墨西哥Sureste盆地是世界级富油气盆地,Salina次盆深水区勘探程度低,相关研究少。基于最新地震地质综合解释结果,并结合区域构造演化和沉积充填特征,论述了该区的石油地质特征与勘探方向。研究表明: Salina次盆构造演化复杂,盐岩活动强烈,控制了烃源岩、沉积储层、构造圈闭、油气运聚和保存等成藏要素。烃源岩为盆地内广泛发育的提塘阶海相页岩,在盐岩发育区具有微盆控烃的特点; 主要勘探目的层系为新近系碎屑岩,沉积与盐构造关系复杂,中新统砂岩储层较发育,物性较好; 次盆在平面上可划分为5个构造单元,主要发育与盐岩相关的背斜、半背斜等类型的圈闭; 盐刺穿褶皱带和盐蓬带成藏条件较好,是最有利的勘探区。     

Exploration prospects of oil and gas in the Northwestern part of the Offshore Indus Basin,Pakistan

Oil and gas resources are short in Pakistan and no commercially viable oil and gas sources have been yet discovered in its offshore areas up to now. In this study, the onshore-offshore stratigraphic correlation and seismic data interpretation were conducted to determine the oil and gas resource potential in the Offshore Indus Basin, Pakistan. Based on the comprehensive analysis of the results and previous data, it is considered that the Cretaceous may widely exist and three sets of source rocks may be developed in the Offshore Indus Basin. The presence of Miocene mudstones has been proven by drilling to be high-quality source rocks, while the Cretaceous and Paleocene–Eocene mudstones are potential source rocks. Tectonic-lithologic traps are developed in the northwestern part of the basin affected by the strike-slip faults along Murray Ridge. Furthermore, the Cretaceous and Paleocene–Eocene source rocks are thick and are slightly affected by volcanic activities. Therefore, it can be inferred that the northwestern part of Offshore Indus Basin enjoys good prospects of oil and gas resources.     

羌塘盆地泥火山发育区天然气水合物地球化学勘查

泥火山是天然气水合物赋存的标志之一,是天然气水合物存在的主要证据.羌塘盆地冻土区发育大量泥火山.对泥火山发育区进行了地球化学勘查,结果表明,泥火山周围具有酸解烃、荧光光谱、碳酸盐、蚀变碳酸盐、微量元素等地球化学指标显著异常,甲烷碳同位素和三维荧光结果显示地球化学烃类异常为原油伴生气和凝析油成因,表明泥火山外围烃类富集是由油气藏渗漏形成.该结论对羌塘盆地天然气水合物勘查突破具有重要意义.     

松辽盆地十屋断陷南部油气勘探前景分析

在十屋断陷以往的油气勘探中,北部地区投入了大量的工作量,发现了后五家户等5个油气田。南部地区虽投入一定的工作量,但未取得实质性的进展。通过对南北地区油气地质条件的对比,从动态的角度对十屋盆地形成演化进行研究,认为十屋盆地南部具有良好的油气勘探前景。     

塔里木盆地和田河气田周缘寒武系盐下白云岩油气勘探潜力分析

塔里木盆地塔西南地区和田河气田周缘寒武系中统发育厚层膏盐岩,其下白云岩溶蚀裂缝-孔洞型储层发育条件好。多个层系具备烃源岩发育条件,除寒武系下统玉尔吐斯组外,震旦系、南华系也是可能的重要生油层系,油气资源丰富。盐下发育多个规模较大的构造圈闭,且由于膏盐岩层的滑脱作用,断裂很难断穿盐层,后期保存条件好。因此,寒武系中统膏盐岩与下伏白云岩组成本区重要的储盖组合,勘探领域具有非常好的前景。     

京张地区延矾盆地北缘活动断裂带桑园镇隐伏段综合地球物理及钻孔地层剖面研究

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