深井换热技术原理及其换热量评估   总被引：10，自引：0，他引：10       下载免费PDF全文

孔彦龙  陈超凡  邵亥冰  庞忠和  熊亮萍  汪集暘 《地球物理学报》2017,60(12):4741-4752

深井换热又称套管换热,是在深井中通过同轴套管进行单井内部流体循环,基于热传导的方式与地层换热,从而以"取热不取水"形式开发地热能的技术.本文详细介绍了深井换热技术特点,评述其在国外的应用进展.国外的实践表明,深井换热延米功率均在200 W以下,多不超过100 W,换热量远小于基于热对流的取热方式,比如深井热水开采技术.本文针对我国北方典型地区地热地质条件,分别采用Beier解析法和双重连续介质数值模拟法(基于OpenGeoSys模拟平台)计算了短期(4个月)采热和长期(30年)采热情景下的换热量.解析法和数值法的结果均表明,延米换热功率上限不超过150W.在间断采热,即每天供热12个小时,停止12个小时的情景下,延米换热功率可以翻倍,但是总换热量基本不变,且水温在一天内的波动明显变大.对数值模型进行敏感性分析发现,在地温梯度一定的条件下,井深对延米换热功率影响不大,而地层热导率对其影响较为明显.最后指出,提高深井换热技术换热量的主要手段是增加井周围地层中的热对流,或者说,增加循环水与岩石的接触面积.  相似文献   

龙门山断裂带北段深部结构与反射地震特征   总被引：2，自引：1，他引：1       下载免费PDF全文

于常青  冯杨洋  瞿辰  范国玮  李恒强 《地球物理学报》2018,61(5):2038-2053

2008年5月12日汶川M_W7.9特大地震发生在龙门山断裂带,龙门山断裂带深部结构的复杂性制约了地震的破裂过程.通过对研究区区域地质、汶川地震前后采集的地震反射剖面等研究,在对龙门山北段汶川地震断裂带的深部结构和反射地震特征进行了分析的基础上,探讨了它对地表破裂过程的制约.研究结果表明,在地震剖面上,断裂带表现为能量破碎、联系性差;频率剖面上显示整体剖面频率在5~45 Hz,断裂带呈现频率低（15~26 Hz）等特征.龙门山北段映秀-北川断裂在10 km以上是一条倾向北西的高角度走滑兼逆冲性质的断裂,倾角50°~70°.它分割了西侧的轿子顶杂岩和东侧的唐王寨推覆体,错断了早期形成的逆冲岩片,从南到北总位移量由大变小.它高角度的几何形态约束了断裂以走滑为主兼逆冲分量的运动性质,降低了地表滑移量,影响了地震破裂过程以及余震沿断裂带两侧分布的特性.  相似文献   

南海构造格局及其演化   总被引：7，自引：0，他引：7       下载免费PDF全文

张功成  贾庆军  王万银  王璞珺  赵庆乐  孙晓猛  谢晓军  赵钊  唐武 《地球物理学报》2018,61(10):4194-4215

依据重磁资料在南海及其邻区识别出17条深大断裂和10个重磁异常区.据此并结合其他地质资料,在南海及其邻区划分出7个地质结构不同的构造单元.早白垩世南海地区曾形成过统一的基底,新生代时统一的南海基底发生肢解,这一个肢解过程经历了两个在时空上接踵发生、交叠作用的构造事件.第一个构造事件为巽他地块与华夏古陆之间古南海的萎缩、闭合和地块碰撞;第二个构造事件为南沙地块裂离华夏古陆并向巽他地块增生,且伴随新南海的持续扩张,直至中中新世.区域构造演化控制了南海沉积盆地呈"北三南三、东西两竖"格局分布,进而控制了油气富集区的分布.  相似文献   

青藏高原东北缘祁连山与酒西盆地结合部深部地壳结构及其构造意义   总被引：2，自引：0，他引：2       下载免费PDF全文

黄兴富  高锐  郭晓玉  李文辉  熊小松 《地球物理学报》2018,61(9):3640-3650

青藏高原地壳变形加厚机制一直是地学界研究争论的热点问题.青藏高原目前仍然处在持续向外扩张之中,因此青藏高原的边界地带作为高原向外扩张的最前缘地区代表了高原最新的变形状态,是研究青藏高原地壳变形加厚的关键地区.本文以一条穿过青藏高原东北缘祁连山与酒西盆地结合部的深地震反射剖面为基础,结合前人地质、地球物理资料,通过细致的地质构造解译,获得青藏高原东北缘祁连山与酒西盆地结合部位地壳变形以壳内滑脱带为界上、下解耦.滑脱带位于壳内低速层的顶部,深度14~24 km.滑脱带之上的地壳部分以一系列南倾、北冲,并向下终止于滑脱带的逆冲断裂变形为主,指示了青藏高原向北的扩张方式;滑脱带之下的地壳以Moho面作为变形标志,指示了复杂的挤压缩短变形.据此我们推测上、下地壳的解耦缩短变形对青藏高原东北缘地壳的变形加厚起到了决定性的作用,甚至在整个青藏高原地壳的变形加厚过程中都起到了重要作用.  相似文献   

马里亚纳海沟万米级水文观测研究     

马克  陈朝晖  李卓然  宋振杰  袁志伟  武斌  焦强  王志民 《海洋与湖沼》2021,52(5):1075-1087

深渊观测是开展深渊科学研究的前提。文章介绍了2020年7月"东方红3"船在马里亚纳海沟"挑战者深渊"附近完成的一次海洋调查。基于船载温盐深综合剖面测量系统获取的万米级剖面数据,分析全海深的温盐性质,并依据Thorpe尺度方法和细尺度参数化方法,进一步估算不同深度层的湍动能耗散率。结果表明:"挑战者深渊"的深层海水十分稳定, 3 000—5 000 dbar的温盐特征与下层绕极水相同;受弱层结背景下的内潮影响, 5 000—8 000 m的耗散率显著提升。本次调查获取的万米级水文剖面为马里亚纳海沟的深渊探索提供了数据方面的支撑。  相似文献   

Upstream perturbation and floodplain formation effects on chute-cutoff-dominated meandering river pattern and dynamics     

Steven A. H. Weisscher  Yasuyuki Shimizu  Maarten G. Kleinhans 《地球表面变化过程与地形》2019,44(11):2156-2169

A sustained dynamic inflow perturbation and bar–floodplain conversion are considered crucial to dynamic meandering. Past experiments, one-dimensional modelling and linear theory have demonstrated that the initiation and persistence of dynamic meandering require a periodic transverse motion of the inflow. However, it remains unknown whether the period of the inflow perturbation affects self-formed meander dynamics. Here, we numerically study the effect of the inflow perturbation period on the development and meander dynamics of a chute-cutoff-dominated river, which requires two-dimensional modelling with vegetation forming floodplain on bars. We extended the morphodynamic model Nays2D with growth and mortality rules of vegetation to allow for meandering. We tested the effect of a transversely migrating inflow boundary by varying the perturbation period between runs over an order of magnitude around typical modelled meander periods. Following the cutoff cascade after initial meander formation from a straight channel, all runs with sufficient vegetation show series of growing meanders terminated by chute cutoffs. This generates an intricate channel belt topography with point bar complexes truncated by chutes, oxbow lakes, and scroll-bar-related vegetation age patterns. The sinuosity, braiding index and meander period, which emerge from the inherent biomorphological feedback loops, are unrelated to the inflow perturbation period, although the spin-up to dynamic equilibrium takes a longer time and distance for weak and absent inflow perturbations. This explains why, in previous experimental studies, dynamic meandering was only accomplished with a sustained upstream perturbation in flumes that were short relative to the meander wavelength. Our modelling of self-formed meander patterns is evidence that scroll-bar-dominated and chute-cutoff-dominated meanders develop from downstream convecting instabilities. This insight extends to many more fluvial, estuarine and coastal systems in morphological models and experiments, which require sustained dynamic perturbations to form complex patterns and develop natural dynamics. © 2019 The Authors. Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd.  相似文献   

The formation and closure of the Big Breach of Sacalin spit associated with extreme shoreline retreat and shoreface erosion     

Florin Iulian Zăinescu  Alfred Vespremeanu-Stroe  Florin Tătui 《地球表面变化过程与地形》2019,44(11):2268-2284

We document a case of exceptionally large natural breaching of a sandy spit (Sacalin spit, Danube Delta) using multiannual to seasonal surveys of topography and bathymetry on successive cross-barrier and shoreface profiles, LiDAR data, satellite imagery, and wind and wave data. The large breach, which quickly reached 3.4 km in May 2014, is attributed to morphological preconditioning of the narrow (50–150 m) barrier, which was susceptible to breaching even during moderate storm conditions. The event switched the barrier's decadal evolution from low cross-shore transport to high cross-shore transport over the barrier, which is an order of magnitude larger than during the non-breach period. Upper shoreface erosion, as indicated by the extensive erosion down to −4 m, indicates that this zone is a significant source for the rebuilding of the barrier. Barrier recovery and widening trigger a negative feedback which limits the back-barrier sediment transfer. As a result, back-barrier deposition decreases whilst the barrier aggradation through overwash becomes more frequent. The Big Breach (TBB) closed naturally in three years. The very high deposition rate of sediment in the breach is a testimony of the high sediment volumes supplied by the longshore transport and the high sediment released through shoreface retreat, and resulted in widening the barrier to a maximum of 1 km. Since the newly-formed barrier shoreline retreated 500 m, this reveals that barrier breaching is an important mechanism which significantly accelerates the landward migration of the barrier system and is a proof of the highly non-linear morphodynamics involved in the barrier island translation. © 2019 John Wiley & Sons, Ltd.  相似文献   

The Inclusions in Superdeep Diamonds: Indication and Response to Deep Mantle Physical and Chemical Environment     

Xinyu Zheng  Zhili Qiu  Xiaoqin Deng  Ying Ma  Taijin Lu 《地球科学进展》2020,35(5):452-464

Superdeep diamonds and their inclusions are important samples to probe the physical and chemical environment and constitution of Earth’s deep mantle. By combining the studies of high-precision in-situ analysis and HPHT synthetic diamond experiments, and by reviewing the new discovery of classical mineral inclusions and their combinations, the ranges of different inclusion combinations, as well as the relationship between trace elements and temperature-pressure conditions were reoriented. The so-called nominally anhydrous minerals combinations, metal phases and redox environments in superdeep mantle were also affirmed. Meanwhile,the recent findings of inclusions and isotopes in superdeep diamonds support the fact that the remaining subduction ocean crust may be a significant reservoir of the deep mantle’s water and the deep mantle carbon cycle is closely related to oceanic subduction. Furthermore, although Chinese scholars have discovered some kinds of superdeep inclusions in diamonds from North China Craton and Yangtze Craton, and made considerable progress in the study of the formation of UHP diamonds and the genesis of ophiolite diamonds, there are still many scientific questions about superdeep diamonds that require further research.  相似文献   

鄂尔多斯盆地延长期富烃坳陷形成的动力学环境与构造属性   总被引：1，自引：1，他引：0  

刘池洋  王建强  邱欣卫  张东东  赵俊峰  赵红格  邓煜 《岩石学报》2020,36(6):1913-1930

鄂尔多斯盆地丰富的石油资源来自盆地南部中晚三叠世延长期富烃坳陷,其中贡献最大的长7段页状优质烃源岩以富铀、夹多层凝灰岩为特征。延长期大型富烃坳陷具南深北浅的坳陷型结构,内部接受统一的湖相沉积。在富烃坳陷的深湖-较深湖区,为优质烃源岩发育区;亦为烃源岩中较高铀含量(测井高伽马异常)和凝灰岩夹层较厚分布区,在位置上三位一体、彼此交互叠置。盆地上古生界-中侏罗统多层系高热演化区上下同位,早-中侏罗世多期持续沉降区先后叠置,均位于延长期富烃坳陷范围内。综合调查研究揭示,在延长期,特别是长7段沉积期间,各类深部物质上拱挤入构造(如砂岩墙(脉)、泥岩脊和热液碳酸盐岩结核)、同沉积变形构造(如断裂、褶皱、揉皱、滑塌、滑坡等(软)地层变形)和事件沉积(如浊流沉积、震积岩及湖底扇等)发育,主要分布在富烃坳陷深湖-较深湖区。在烃源岩等地层中,检测出多种指示深部热流体活动的岩石矿物和地球化学异常。深部探测显示,在富烃坳陷深部400km以上壳幔各界面呈上拱的结构特征。这表明延长期富烃坳陷和其中优质烃源岩是在构造活动明显、深部作用活跃的地球动力学环境中形成演化的,从深层次揭示了其形成条件与发育环境。延长期富烃坳陷与印支期秦岭造山带的形成演化及其岩浆活动,在空间上相邻、发育时限相当、演化阶段响应、活动兴衰同步,是在华北-扬子两大陆块汇聚碰撞,进而向板内构造环境转换的动力学环境中进行的。延长期富烃坳陷两次较长距离的沉积-沉降中心迁移,是对秦岭碰撞造山环境重大变革始发的响应和纪录。在南北两大陆汇聚碰撞过程中,在仰冲华北板块后陆地带深部积聚的巨量俯冲物质发生熔融和热量转换,促使该区深部物质过饱和聚集、热能及压力超常骤增,形成较小尺度地幔对流,熔融物质与热能上拱,引发地壳表浅层拱张破裂和侧向扩展,于是发生沉降,形成延长期具热-张性特性的富烃坳陷,称其为后陆盆地。后陆盆地与前陆盆地分别位于碰撞造山带两侧仰冲和俯冲板块临山一侧,但其构造属性有质的不同,油气赋存和成藏特征也差别较大。  相似文献   

Cymrite as mineral clathrate: An overlooked redox insensitive transporter of nitrogen in the mantle     

《Gondwana Research》2020

We study the phase relations and mineral chemistry in the systems muscovite–NH₃–N₂-H₂O and eclogite + muscovite–NH₃–N₂-H₂O at 6.3–7.8 GPa, 1000–1200 °C, and oxygen fugacity (fO₂) from ∼IW (Fe–FeO) to ∼ NNO (Ni–NiO) equilibria. The quenched H₂O-bearing fluids differ in nitrogen speciation from NH₃-rich to N₂–rich, and the respective N₂/(NH₃+N₂) ratio varies from <0.1 to ∼ 1. N-bearing K-cymrite is obtained in association with a kyanite-garnet-jadeite ± muscovite ± corundum assemblage in the muscovite–NH₃–N₂-H₂O system and coexists with pyrope-almandine garnet and omphacite in the eclogite + muscovite–NH₃–N₂-H₂O system. The presence of an N-bearing fluid in the studied systems stabilizes the K-cymrite structure. Muscovite does not convert to K-cymrite in the absence of NH₃–N₂-bearing fluid up to 7.8 GPa and 1070–1120 °C. According to FTIR and Raman spectroscopy, K-cymrite in equilibrium with an N-rich fluid can capture a huge amount of nitrogen in cages of its framework, mainly as N₂ molecules at fO₂ ∼NNO and predominantly as NH₃ molecules at fO₂ ∼IW. The storage capacity of K-cymrite with respect to nitrogen increases from 2.9 to 6.3 wt% with increase of fO₂. FTIR spectroscopy of muscovite equilibrated with K-cymrite shows that the clathrate mechanism of nitrogen entrapment by aluminosilicates (as neutral N₂ and NH₃ molecules) is much more efficient than the K⁺ → (NH₄)⁺ substitution. The structure of N-bearing K-cymrite (K,(NH₄⁺))[AlSi₃O₈]·(N₂,NH₃,H₂O) determined using X-ray single-crystal diffraction is very similar to that of H₂O-bearing K- and Ba-cymrites. It includes aluminosilicate layers consisting of double six-membered tetrahedral rings and cation sites statistically occupied with K⁺, Ba²⁺ and (NH₄)⁺ on the six-fold symmetry axis in interlayer space. The N₂ and NH₃ molecules are located near the cage centers and, unlike H₂O molecules, are included in the coordination environment of the cations. Our study confirms that NH₃- and N₂-rich K-cymrite may be stable in metapelites and can act as a redox insensitive carrier of nitrogen to >250 km mantle depths in downgoing slabs. The stability field of N-rich K-cymrite in the presence of an N₂–H₂O–NH₃-bearing fluid is inferred to be P ≥ 4 GPa in metasediments rich in K-feldspar and P ≥ 6 GPa in those containing phengite. As the slab material sinks deeper than 250–300 km where N-bearing K-cymrite may lose stability, the releasing nitrogen may migrate to metal-saturated mantle and become stored there in γ−Fe, Fe₃C, metal melt, or even iron nitride phases.  相似文献