华北平原地貌区划新见

在埋深20~15 m(山前平原)或10~8 m(中部和滨海平原)以上的三维空间,将地貌形成演化的同一时段,具有同一结构、构造特征的组成物质和形态-成因上有相互联系的地貌类型的组合体视为一个地质-地貌体。基于这一观点,将冲积扇从传统地貌区划中的"山前倾斜平原区"中分离出来,与冲积泛滥平原合并,称作"中部冲积扇-冲积泛滥平原区",更符合国民经济合理布局的需要。     

Denudation intensity and control in the Chinese Tian Shan: new constraints from mass balance on catchment‐alluvial fan systems

Tectonics and climate are usually seen as the main controlling factors of denudation rates, which seem to rise with the tectonic activity and to decrease when the climate becomes drier. However, the low denudation rates observed in semi‐arid to arid contexts are generally measured on orogenic plateaus where the respective influence of the flat relief and the dry climate cannot really be unravelled. The Chinese Tian Shan was chosen as a case study. In the northern piedmont of this mountain range, a series of well‐preserved Quaternary alluvial fans offer the opportunity to perform a mass balance study at the scale of several catchment areas and several hundreds of thousands of years. Based on a geometrical reconstruction of these fans, the volumes of sediments exported out of 10 drainage basins during the Middle–Late Pleistocene (from ～300 to ～12 kyr) and the Holocene (from ～12 kyr to present) have been estimated. From these volumes, an average denudation rate of ～135 m/Myr was determined in the Tian Shan Range for the last 300 kyr. In agreement with other mass balances performed in the same area, the typical denudation intensity of the northern Tian Shan is thus of a few hundred meters per million years at most, regardless of the space and time scales considered. From a comparison with denudation rates in other mountain ranges throughout the world, we suggest that a dry climate can dramatically limit the denudation intensity even in active orogenic systems with a high topographic gradient like the Tian Shan. As a result, the time required to reach equilibrium between denudation and rock uplift in these systems could be extremely long (i.e. of more than several million years). Copyright © 2016 John Wiley & Sons, Ltd.     

中国东部陆相断陷盆地成熟探区油气勘探新领域分析*

经过50多年勘探开发,中国东部陆相油气田均已进入勘探中后期阶段,受石油地质认识局限性和勘探技术的限制,待发现目标日趋隐蔽,油气勘探难度日益增大。针对中国东部陆相断陷盆地深层低孔渗—致密砂岩储集层评价方法的局限性、深部砂砾岩储集体成因模式问题以及基岩风化壳形成和分布的复杂性问题,作者经过近几年的探索和总结,取得以下主要研究进展: (1)基于砂岩储集层物性演化动力学原理,提出了致密砂岩储集层动态评价的新思路和新方法,指出过去评价较低的深部凹陷带低孔渗—致密砂岩体仍然具有较大的勘探潜力; (2)运用地震地层学方法,通过建立断陷盆地陡坡带斜向大型扇三角洲沉积模式,指出斜向大型扇三角洲砂砾岩是断陷盆地深层有利的储集体,可以作为下一步有利勘探方向; (3)根据基岩风化壳双层结构新模式,结合风化壳储集层改造—破坏—保存机理的动力学新模型,指出断陷盆地中低部位是最有利风化壳储集层发育带,断陷盆地缓坡内带(洼槽区)风化壳是下一步油气勘探的重要新领域。文中提出的上述3大勘探新领域不仅是对断陷盆地油气成藏模式的补充和发展,更重要的是展现出中国东部断陷盆地深层常规和非常规油气勘探领域的巨大潜力,为深化东部成熟盆地油气勘探指出了明确的方向。     

Morphological records of storm floods exemplified by the impact of the 1872 Baltic storm on a sandy spit system in south‐eastern Denmark

Beach‐ridge systems are important geo‐archives providing evidence for past wave climate including catastrophic storm flood events. This study investigates the morphological impacts of the 1872 Baltic storm flood on a beach‐ridge system (sandy spit) in south‐eastern Denmark and evaluates the frequency of extreme storm flood events in the area over a longer time perspective. This paper combines field studies of morphology and sedimentary deposits, studies of historical maps, digital terrain model, ground‐penetrating radar profiles, and luminescence dating. Sea water reached 2.8 m above mean sea level (amsl) during peak inundation and, based on studies of the morphological impacts of the 1872 storm flood, the event can be divided into four phases. Phase 1: increasing mean water levels and wave activity at the beach brought sediments from the beach (intertidal bars and normal berm) higher up in the profile and led to the formation of a storm‐berm. Phase 2: water levels further increased and sediment in the upper part of the profile continued to build up the storm‐berm. Phase 3: water levels now reached the top of the dune ridge and were well above the storm‐berm level. Sea water was breaching the dune ridge at several sites and wash‐over fans were generated until a level where the mean water level had dropped too much. Phase 4: the non‐vegetated wash‐over fans functioned as pathways for aeolian sand transport and relatively high dunes were formed in particular along the margins of the fan where aeolian sand was trapped by existing vegetation. The studied beach‐ridge system records about 4500 years of accumulation; the storm flood sediments described are unique suggesting that the 1872 Baltic storm flood event was an extreme event. Thus studies of beach‐ridge systems form a new source for understanding storm surge risk. Copyright © 2013 John Wiley & Sons, Ltd.     

湖北省广北油田潜三段下部湖底扇沉积特征分析

从区域地质背景出发 ,结合岩心观察、粒度分析、镜下鉴定结果及测井曲线形态等进行综合分析表明 ,位于蚌湖向斜东南斜坡的湖北省广北油田Eq341沉积时属半深湖—深湖背景下的湖底扇相沉积 ,可细分为内扇、中扇和外扇 3个亚相 ,其中中扇可细分出辫状沟道、辫状沟道间和扇中前缘 3个微相。根据测试资料分析 ,有辫状沟道的中扇为有利相带 ,指出蚌湖向斜东南斜坡、钟市陡坡三角州前缘是寻找油藏的有利区带。     

柴达木盆地切12区沉积层序及对油气富集的控制作用

柴达木盆地昆北油田切12区发育厚层砂砾岩油藏。砂砾岩成因类型及分布规律认识不清是制约油藏开发的关键地质因素。综合利用地质、测井、地震及开发动态等资料,在等时层序地层格架内,系统研究砂砾岩的成因类型、分布规律及其对油气富集的控制作用。研究结果表明,切12区下干柴沟组下段发育冲积扇沉积,可划分出辫状水道、泥石流、漫流沉积、径流水道及洪泛平原5种沉积微相类型,可建立“泛连通体”夹间歇性水道、稳定水道形成的叠置分隔复合水道、辫状水道与漫流沉积侧向相间、径流水道镶嵌于洪泛平原泥岩4个沉积构型单元。垂向上,冲积扇整体表现为粒度下粗上细、湖进退积型的沉积序列;平面发育6个冲积扇体,呈由北向南迁移的规律。沉积相带对油气分布具明显控制作用,沉积构型单元控制油气纵向富集,扇体变迁控制油气平面聚集。     

北部湾盆地福山凹陷深湖重力流成因分类、发育机制及沉积模式

福山凹陷为北部湾盆地南缘海南隆起斜坡上的一个新生代断陷湖盆。本文充分利用岩心、测井以及覆盖整个研究区的高分辨率三维地震资料,以层序地层学、沉积学等多种理论为指导,结合沉积岩石学、地震沉积学等相关技术,于古近系流沙港组SQEls₂EST+LST时期,在福山凹陷识别出4种深湖重力流沉积岩相类型;通过岩相组合及其转换特征、砂分散体系、地震相分析,对该时期沉积体系展布特征进行细致剖析,进而建立福山凹陷深湖重力流发育机制和沉积模式：西部地区发育以浊流为主、具有典型浊积水道的湖底扇沉积;而东部地区则以砂质碎屑流沉积形成的远端孤立朵体为主。     

丽水凹陷远岸水下扇体识别及特征分析

在丽水凹陷西次凹西部斜坡带发育多条坡折断层,它们控制了古新统明月峰组下段远岸水下扇体的发育。钻井揭示该区水下扇体具有沉积厚度大、物性好、含油气性活跃的特征。储层特征描述、分布范围预测对寻找本区岩性油气藏具有重要意义。本文通过对明月峰组沉积初期古地貌恢复,总结了坡折断层对扇体发育的影响作用。坡折断层上升盘发育孤立型和复合型水道;坡折断层下降盘发育扇体主体,扇中水道微相为优势相带,岩性以灰色细砂岩为主,存在反映垮塌变形的泄水、泥质火焰等沉积构造,测井相表现为低伽马、高自然电位异常,地震相为强振幅、低频、断续反射。同时,利用地震沉积学技术完成了本区3期次扇体分布范围识别,说明自早期到晚期扇体具有从北往南逐渐迁移的特征。     

新疆克拉玛依油田八区上二叠统下乌尔禾组河控型扇三角洲沉积

从岩心、薄片等实际资料着手,结合EMI成像测井等现代技术研究,认为新疆克拉玛依油田八区上二叠统下乌尔禾组属河控型扇三角洲相沉积,并识别出两种亚相和9种微相：2种亚相是扇三角洲平原和扇三角洲前缘亚相,而前扇三角洲不发育。9种微相是辫状河道沉积、漫流沉积、泥石流沉积、筛滤沉积、水下分流河道沉积、水下分流河道间沉积、水下天然堤沉积、碎屑流沉积及颗粒流沉积。同时,以成像测井资料为主要依据,结合岩石粒度及成分特征分析,表明研究区下乌尔禾组5个时期的物源方向不尽一致,表现为从早到晚,由第5亚期至第1亚期,物源方向由以西南方向为主,逐渐变为以西北为主。与物源变化相对应,沉积相也呈现有规律的变化。本文在对沉积相进行详尽研究的基础上,深入解剖了克拉玛依油田上二叠统下乌尔禾组的沉积微相特征,阐明了沉积相的展布和演化。     

西藏羌塘盆地北部托纳木地区上侏罗统雪山组沉积相

羌塘盆地地处藏北高原,其南、北边界分别为班公错一怒江缝合带与拉竹龙一金沙江缝合带,盆地面积约18×10⁴km²,可进一步分为羌北坳陷、中央隆起带和羌南坳陷3个二级构造单元.双湖托纳木地区地处羌北坳陷南部,与中央隆起带毗连,广泛发育上侏罗统雪山组沉积,垂向上由3个沉积旋回组合构成,总体显示为一个向上变粗的充填序列.雪山组发育扇三角洲相和冲积扇相,其中雪山组一段为前扇三角洲亚相沉积;二段为扇三角洲前缘亚相和扇三角洲平原亚相沉积,扇三角洲前缘亚相分为水下分流河道、河口坝和远砂坝沉积,扇三角洲平原亚相发育天然堤和分流河道沉积;三段为冲积扇相沉积,包括扇端和扇中沉积.雪山组沉积的物源来自西南部的中央隆起带.