裂谷盆地火山活动与油气藏的形成

我国东部裂谷盆地主要生储油层系中常发育有基性浅成侵入岩、火山岩和火山碎屑岩。在火成岩发育区常见油气富集 ,并伴有非烃气藏。喷发在生油岩沉积环境中的玄武岩及其火山碎屑岩可以改变有机质富集状况 ;侵入生油层的辉绿岩等可以使局部具有特殊的油气生成能力 ;火山活动放出的二氧化碳等非烃气体可以直接形成气藏。研究发现 ,火成岩发育区的生油岩具有早熟和油气生成量特别大等特点 ;火成岩发育区一般是盆地内构造应力低值区 ,也是圈闭和油气藏集中发育区。此外 ,火成岩及相关油气藏具有储集空间发育、油气充注率高、油气保存条件好等优点。以东营凹陷等火成岩发育区为实例 ,分析并阐明了有关问题     

Episodic rifting of continental marginal basins and tectonic events since 10 Ma in the South China Sea

Integrated study on the tectonic, basin filling and thermal evolution of the Tertiary basins on the northern margin of the South China Sea has indicated that the rift continental margin on the northern South China Sea is not a passive margin and that the western margin is characteristic of the transform-extension. Episodic rifting and the thermal events since 10 Ma in the area have been documented by the integrated analysis of dynamic process. It has been clarified that the tectono-thermal events have exerted a significant influence on basin features and hydrocarbon accumulation, and particularly, the westward collision of the Lusong Island Arc, the generation of densely spaced faults in the Pearl River Mouth Basin, the rapid subsidence, high heat flow and large-scale over pressure and thermal-fluid breakthrough in the Yinggehai and the Qiongdongnan basins have proved to be the important factors determining the formation of oil and gas in these basins.     

Nd isotopic variations and its implications in the recent sediments from the northern South China Sea

The chondrite-normalized REE distribution patterns in recent sediments from the northern South China Sea and surrounding areas are similar, with the HREE values being almost equal to or slightly higher, and the La_N/Lu_N ratio being lower, than PAAS standards. However, samples from the Xijiang River, a major branch of the Pearl River system, show opposite trends, i.e., with slightly lower HREE values and higher La_N/Lu_N ratio than PAAS. The distribution of Nd isotopes in sediments from the northern South China Sea was controlled by the Pearl River and the inshore area of South China, respectively. The volume of ε_Nd(0) from inshore areas of southern China is apparently higher than that from the Pearl River, and ε_Nd(0) values in offshore sediments and Taiwan Island are between these values. The results clearly show that ε_Nd(0) volume in the northeastern South China Sea is higher than in the southwest part of the northern South China Sea, indicating different source rock types. The main source rock of the Pearl River sediment is carbonate types and affects sediment deposition in the southwest of the northern South China Sea, while the source rock in the inshore area of southern China, mainly Mesozoic and Cenozoic granites, contributes to sediments in the northeastern area of the northern South China Sea. Due to different source rock types, the HREE values and the volume of ε_Nd(0) in recent sediments supplied by the inshore area of southern China are higher than those from the Pearl River. Over 80% of the rapidly accumulated sediments on the northern slope of the South China Sea in the southeast of Dongsha Islands area were derived from Taiwan Island and from inshore areas of South China, with only less than 20% from the Pearl River. Supported by National Natural Science Foundation of China (Grant Nos. 40276019, 40238060 and 40621063), and National Basic Research Program of China (Grant No. 2007CB819501)     

南海北部深水油气新认识

 南海北部陆缘深水区由于陆缘地壳的强烈伸展减薄，形成了多个宽深断陷所构成的盆地群，发育多种类型烃源岩和大型储集砂体。大型盆地、广泛分布的多类型烃源岩、高-变地温场的耦合共控，奠定了深水油气资源的物质基础。大型供给水系、构造地貌、相对海平面升降的相互作用，形成3种类型的沉积体系，控制了深水区大型储集体的发育和展布，但高热流加速了深水沉积物压实和成岩作用。南海北部陆缘深水油气勘探前景广阔，烃源岩、有效储层以及热流3因素的复杂多变，决定了油气勘探中机遇与挑战并存。     

中国南海油气资源前景

南海处于欧亚板块、太平洋板块和印—澳板块三大板块的交汇处,经历了复杂的地质作用和演化过程,在其北部、西部和中南部形成了数目众多、类型各异的沉积盆地,石油地质条件优越,油气资源潜力巨大。其中南海北部陆架区已经成为中国近海的主要油气产区之一,陆坡深水区的勘探也获得了重大突破。目前,我国传统疆域内的油气资源正在不断受到南海周边国家的蚕食,因此,应该加快南海地区的油气资源勘探,切实维护国家主权和领土完整。     

Deep crustal structure of Baiyun Sag,northern South China Sea revealed from deep seismic reflection profile

This paper discusses deep crustal architecture of the Baiyun Sag of the Pearl River Mouth Basin, northern South China Sea based on velocity analysis, time-depth conversion and seismic interpretation of the deep seismic reflection profile DSRP-2002. The profile was acquired and processed to 14 S TWT by the China National Offshore Oil Corp. (CNOOC) in 2002. It extends across the Baiyun Sag of the Pearl River Mouth Basin, from the northern continental shelf of the SCS to the deepwater province. As the first deep seismic reflection profile in the Pearl River Mouth Basin, this profile reveals seismic phases from basement down to upper most mantle. The Moho surface appears in the profile as an undulating layer of varying thickness of 1-3 km. It is not a single reflector interface, but a velocity gradient or interconversion layer. The crust thins stepwisely from the shelf to the continental slope and the abyssal plain (from north to south), and also thins under depocenters. The crustal thickness is only 7 km in the depocenter of the main Baiyun Sag, which corresponds to a Moho upwelling mirroring the basement topography. In the lower slope and the ocean-continental transition zone of the southernmost portion of the profile, three sub-parallel, NW-dipping strong reflectors found at depths around 10--21 km are interpreted as indications of a subducted Mesozoic oceanic crust. Crustal faults exist in the northern and southern boundaries of the Baiyun Sag. The intense and persistent subsidence of the Baiyun Sag might be related to the long-term activity of the crustal faults.     

新生代早期南海北部水系演变

 珠江在早渐新世仅是涉及华南沿海地区的小河；到晚渐新世，向西延伸到云贵高原前缘地带；到中新世，现代珠江流域格局初步形成。证据显示，南海北部还发育过一条源自南海西部隆起区的大型水系-昆莺琼古河，后淹没在南海之中，但在南海的沉积充填过程中扮演了重要角色。南海北部水系及沉积环境的重建，对于深刻认识南海新生代早期古地理特征以及该地区的油气勘探均具有重要意义。     

珠江口盆地琼海凸起断裂调整聚集成藏模式

针对油气分布规律认识问题,运用油气地球化学、构造解析方法,开展了中新世构造运动背景下珠江口盆地 琼海凸起中新统珠江组油藏的调整、次生油藏形成机制的研究。以地层界面T41（珠江组一段IV 油组顶）为界的珠江 组上、下部油藏,分别具有“晚期聚集”和“晚期断裂调整”特征,下部油藏原油密度高、黏度大;上部油藏原油密度低、 黏度小。珠江组上、下部油藏油气来源相同。中中新世的NWW- SEE 走向雁列式断裂体系沟通了珠江组上、下部油 藏,起到了调整改造下部油藏和向上部运移油气的双重作用。提出了“晚期断裂调整、晚期聚集”油气成藏模式,即由 于晚期断裂的垂向沟通,早期形成的珠江组下部油藏中局部油气沿断裂向上部运聚,调整后的下部油藏、晚期聚集的 上部油藏垂向叠置,形成“下重上轻”、多油水系统的油田,对研究区油气勘探开发具有重要指导意义。     

多井约束条件的宽频速度建模方法

针对南海东部珠江口盆地目前勘探遇到的低幅构造难以落实的问题,应用基于多井约束条件下的宽频速度建模技术建立区域速度模型,落实靶点构造形态。讨论了该方法的思想、技术路线和应用步骤,并与PSDM方法得到的深度构造图进行了对比分析。实测数据处理结果表明：多井约束条件下的宽频速度建模技术受断层的影响存在一定的绝对误差,但同一层位的相对误差较小,研究工区速度体刻画更为准确,能更好地刻画低幅构造形态。探索出了一套针对南海东部珠江口盆地低幅构造的宽频速度建模分析方法。     

Late Miocene Red River submarine fan,northwestern South China Sea

A huge submarine fan is discovered through the research of the seismic and borehole data in the binding site of Yinggehai basin and Qiongdongnan basin in northwestern South China Sea.The fan,mainly formed during Late Miocene (Huangliu period) has an area over 10000 km 2 and maximum thickness of over 2000 m.It is characterized by a wedge-shaped oblique progradation configuration on the dip profile and a hummocky bidirectional progradation configuration on the strike profile.The core and Logging data from the well YC35-1-2 located in the front side of the fan indicate that sandy gravity flow deposits are predominant in lower Huangliu Formation and change to interbeds of sand and mud in upper Huangliu Formation.The fan is interpreted as a sand/mud-rich submarine fan in combination with the bathyal geological background of Huangliu period.A preliminary analysis of provenance indicates that neither the Guiren Uplift in the west nor the Hainan Uplift in the north can serve as the major provenance for the submarine fan.The provenance is considered to be from the Red River,based on the sedimentary facies study of the Huangliu Formation in Yinggehai basin.The fan is thus named as "Red River submarine fan".The Red River depositional system consists of the Red River submarine fan,the Red River delta,and associated submarine canyons.The discovery of the Red River submarine fan provides important information for the research of the uplift of Tibetan Plateau and the evolvement of Red River Fault Zone.Furthermore,it also points out a new direction for the deepwater hydrocarbon exploration in the northern South China Sea.     

珠江口盆地西部生物礁与火山岩的辩证识别

探讨生物礁与火山岩等疑似礁体的辩证差异,厘清珠江口盆地西部浅层地震异常体的地质属性。从琼海24-2异常体所处地理环境出发,结合南海北部生物礁发育的大背景和珠江口盆地生物礁发育的演化规律,重点从生物礁发育所必备的各种地质条件及其地震响应特征进行辩证分析。结果表明琼海24-2异常体所处地理环境不具备生物礁发育的地质条件,地震反射特征具有明显的火山穿刺现象,且属后期破坏型火山活动,因此琼海24-2是受火山活动影响复杂化的异常体,不是生物礁,也不满足火山旁侧发育生物礁的模式,勘探风险较大。     

南海珠江深水扇系统的沉积构造背景分析

从深水扇系统的观点出发,主要基于对最近所采集的穿越整个白云凹陷的700余公里长电缆深反射(深达14 s)地震资料综合解释,结合南海大洋钻探的成果,对南海珠江深水扇系统沉积的构造背景特征进行了综合分析.研究发现:白云主凹在早中新世-中中新世期间(即大约距今25～10 Ma)是一个因坳陷期盆地基底的持续沉降及其相关断裂活动而形成的南海北部陆缘上的斜坡内盆地;白云主凹这个"斜坡内盆地"有别于世界上其它位于被动大陆边缘背景中(如西非近海、巴西近海、墨西哥湾)的斜坡内盆地;海平面变化、沉积物通量变化、构造活动等地质营力都在斜坡内盆地的构造背景上对南海珠江深水扇系统在不同时期产生了不同程度的重要影响.简言之,斜坡内盆地成就了南海珠江深水扇系统.这为以后进一步全面深入研究南海珠江深水扇系统的形成机制、演化过程、结构特征等有着重要意义.     

珠江口盆地惠州凹陷西区珠江组层序地层学研究

珠江口盆地惠州凹陷西区油气资源丰富,珠江组作为主要的储集层发育层段,是该区增储上产的主力产层。在充分利用钻、测井及地震资料的基础上,以层序地层学理论为指导,结合前人研究成果,分析了珠江口盆地惠西地区珠江组各级次层序界面特征,确定了层序界面的识别标志。在工区内共识别出1个二级层序界面,5个三级层序界面,划分为5个三级层序,并根据三级层序内部不同类型的水进界面进一步细分为21个四级层序。通过井-震对比,建立了工区内珠江组层序地层等时格架,揭示了各沉积层序的发育特征,对今后珠江口盆地的油气勘探有重要指导意义。     

深水钻井隔水管与井口技术研究进展

钻井隔水管与井口系统是深水钻井装备中重要而薄弱的环节,其正确设计与使用直接关系到钻完井作业的顺利完成。系统开展了面向南海的深水钻井隔水管与井口技术研究,建立其力学分析方法,形成一套深水钻井隔水管与井口系统钻前设计与作业技术体系;提出隔水管与井口系统的波激疲劳、涡激疲劳、磨损以及隔水管接头完整性评估方法,并进一步完善深水钻井隔水管与井口完整性管理方案;建立深水钻井隔水管关键装备与作业风险评价框架,探索台风环境下的隔水管系统安全保障的关键技术;在此基础上开发深水钻井隔水管作业管理软件,承担中国南海6口自营深水井的隔水管与井口系统钻前设计与作业技术研究工作,成功将科研成果应用到深水钻井实践中,并取得良好的应用效果。笔者对这些进展进行总结和回顾,并对今后的研究方向进行展望。     

番禺低隆起三级层序的界面识别标志及沉积特征

 番禺低隆起地区是珠江口盆地最有利的油气勘探区域之一,目前已经在该区发现了多个气田和含气构造,天然气地质储量达1200亿m³,成藏条件非常有利。随着勘探的不断深入,目前面临着可供钻探的构造目标越来越少的难题。通过对珠江口盆地番禺低隆起三维地震资料解释,结合钻井、古生物、测井等资料,开展层序划分对比工作,建立区域层序地层格架,揭示了研究区三级层序界面的识别标志及等时地层结构的基本特征,并对层序格架内沉积相的构成、分布特征及演化、有利储盖组合特征进行了研究,对今后该区的油气勘探具有重要指导意义。     

Distribution and identification of the low-velocity layer in the northern South China Sea

The low-velocity layer (LVL), closely related with tectonic activities and dynamic settings, has always been a hot topic in the deep crustal structure studies. The deep seismic (OBS/OBH) and onshore-offshore experiments have been extensively implemented in the northern South China Sea (SCS) since the 1990s. Six seismic profiles were finished on the northern margin of SCS by domestic and international cooperations. The features of crustal structures were revealed and five velocity-inversion layers were discovered. Among them three LVLs with 3.0—3. 5 km·s-1 velocity are located in the sedimentary structure (2.0—6.0 km in depth and 2.0—4. 6 km in thickness) of the Yinggehai Basin and Pearl River Mouth Basin. They were identified by the reflective and refractive phases for their shallow depth. The other two LVLs with 5.5—6.0 km·s-1 velocity generally existed in the middle crust (7.0—18.0 km in depth) with an about 2.5—6.0 km thickness in the transitional crustal structure of the northeastern and northwestern SCS. They were detected by the refractive phase from their overlain and underlying layers. We explored the possible tectonic formation mechanisms combining with previously reported results, which provided evidence for the formation and evolution of SCS.     

Clay minerals in surface sediments of the Pearl River drainage basin and their contribution to the South China Sea

Clay minerals have played a significant role in the study of the East Asian monsoon evolution in the South China Sea by being able to track oceanic current variations and to reveal contemporaneous paleoclimaUc changes prevailing in continental source areas. As one of the most important rivers inputting terrigenous matters to the northern South China Sea, the Pearl River was not previously paid attention to from the viewpoint of clay mineralogy. This paper presents a detailed study on clay minerals in surface sediments collected from the Pearl River drainage basin （including all three main channels, various branches, and the Lingdingyang in the estuary） by using the X-ray diffraction （XRD） method. The results indicate that the clay mineral assemblage consists dominantly of kaolinite （35%-65%）, lesser abundance of chlorite （20%-35%） and illite （12%-42%）, and very scare smectite occurrences （generally 〈5%）. Their respective distribution does not present any obvious difference throughout the Pearl River drainage basin. However, downstream the Pearl River to the northern South China Sea, the clay mineral assemblage varies significantly： kaolinite decreases gradually, smecUte and illite increase gradually. Additionally, illite chemistry index steps down and illite crystallinity steps up. These variations indicate the contribution of major kaolinite, lesser illite and chlorite, and very scarce smecUte to the northern South China Sea from the Pearl River drainage basin. The maximum contribution of clay minerals from the Pearl River is 72% to the northern margin and only 15% to the northern slope of the South China Sea. In both glacials and interglacials, kaolinite indicates that the ability of mechanical erosion occurred in the Pearl River drainage basin.     

烃源岩TOC地球物理定量预测新技术及在珠江口盆地的应用

南海东部珠江口盆地富生烃洼陷内部的钻井极少,给烃源岩总有机碳含量(TOC)地球物理预测研究及洼陷的资源潜力评价带来了极大的困难。结合烃源岩测井及地震响应特征,从实测有机碳含量出发,应用测井预测TOC的方法建立虚拟井的TOC曲线,以此为因变量,选取的地震属性作为自变量,建立它们之间的最佳拟合方程,通过三维地震数据体中提取地震属性从而计算得到三维TOC数据体。将该方法应用到珠江口盆地富生烃洼陷惠州洼陷中,得到整体文昌组和恩平组的三维TOC数据体。HZ26洼陷边缘到洼陷深部,有机碳含量明显增大,反映了洼陷深部是优质烃源岩的发育场所,从南部隆起区到洼陷深部,再到北部洼陷边缘,先增大后又逐渐减小的变化特征。     

准噶尔盆地南缘西部东湾背斜带构造演化及含油气性分析

通过分析准噶尔盆地东湾背斜带的构造形成、演化及特征,认为主要是由于来自喜马拉雅运动南北向的挤压力及上覆地层自身重力的双重作用下形成了东湾背斜及上覆宽缓向斜带,讨论了东湾背斜带的含油气性,分析了东湾1井的失利原因是由于受断层活动的影响所致,指出了东湾背斜带有利的勘探目标区是靠近滑脱推覆体的下盘地层,并且在侏罗系中有可能发现自生自储的油气藏.     

中国近海基岩油气藏分布特征及其控制因素

基岩油气藏已成为中国海域油气勘探的增储上产的重要领域.基岩油气藏主要发育在裂陷盆地、走滑盆地和前陆盆地,具有"新生古储"的特点.中国海域基岩油气藏分布具有平面广、纵向层系多的特点,储层类型主要以前寒武系变质岩和混合花岗岩、古生代碳酸盐岩、中生代火山岩以及花岗岩侵入体、中生代碎屑岩为主.通过分析海域基岩油气藏空间分布规律...