Holocene relative sea level history and Storegga tsunami run‐up in Lyngen,northern Norway          下载免费PDF全文

Henrik Rasmussen  Stein Bondevik  Geoffrey D. Corner 《第四纪科学杂志》2018,33(4):393-408

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新时期新疆水库大坝建设的主要问题与对策建议          下载免费PDF全文

李江  柳莹  刘生云  彭兆轩  吴涛 《干旱区地理》2020,43(6):1409-1416

截止 2018 年，全疆（含兵团）已建、在建及拟建水库 722 座（包括电站水库），总库容 295.0 × 10⁸ m³。有力地改善了水资源调控和利用效率，在灌溉、供水、防洪、发电、旅游等方面发挥了极其 重要的作用。新时期按照水利部“水利工程补短板、水利行业强监管”的工作总基调，针对南北疆 水资源配置不平衡问题、水资源利用不充分问题，谋划提出了兴建数十座大中型山区水库，以及提 升已建水库大坝信息化管理水平、加强水库调度运行管理，在满足生态需水的前提下统筹生活、生 产供水，最大程度发挥水库效益、确保水库安全运行。针对新时期气候变化条件下水库洪水风险 分析、大坝建设需要重点关注的几项关键技术、山区水库替代平原水库、河流健康与生态调度、水库 清淤与能力提升、水库信息化与智能调度以及延长服役期等问题进行了探讨，提出若干对策建议。  相似文献   

地震油气储层的小样本卷积神经网络学习与预测   总被引：2，自引：0，他引：2       下载免费PDF全文

林年添  张栋  张凯  王守进  付超  张建彬  张冲 《地球物理学报》2018,61(10):4110-4125

地震储层预测是油气勘探的重要组成部分，但完成该项工作往往需要经历多个环节，而多工序或长周期的研究分析降低了勘探效率.基于油气藏分布规律及其在地震响应上所具有的特点，本文引入卷积神经网络深度学习方法，用于智能提取、分类并识别地震油气特征.卷积神经网络所具有的强适用性、强泛化能力，使之可以在小样本条件下，对未解释地震数据体进行全局优化提取特征并加以分类，即利用有限的已知含油气井段信息构建卷积核，以地震数据为驱动，借助卷积神经网络提取、识别蕴藏其中的地震油气特征.将本方案应用于模型数据及实际数据的验算，取得了预期效果.通过与实际钻井信息及基于多波地震数据机器学习所预测结果对比，本方案利用实际数据所演算结果与实际情况有较高的吻合度.表明本方案具有一定的可行性，为缩短相关环节的周期提供了一种新的途径.  相似文献   

Operation of two major reservoirs of Iran under IPCC scenarios during the XXI century          下载免费PDF全文

Habib Akbari‐Alashti  Andrea Soncini  Yagob Dinpashoh  Ahmad Fakheri‐Fard  Siamak Talatahari  Daniele Bocchiola 《水文研究》2018,32(21):3254-3271

We assess the effects of prospective climate change until 2100 on water management of two major reservoirs of Iran, namely, Dez (3.34 × 10⁹ m³) and Alavian (6 × 10⁷ m³). We tune the Poly‐Hydro model suited for simulation of hydrological cycle in high altitude snow‐fed catchments. We assess optimal operation rules (ORs) for the reservoirs using three algorithms under dynamic and static operation and linear and non‐linear decision rules during control run (1990–2010 for Dez and 2000–2010 for Alavian). We use projected climate scenarios (plus statistical downscaling) from three general circulation models, EC‐Earth, CCSM4, and ECHAM6, and three emission scenarios, or representative concentration pathways (RCPs), RCP2.6, RCP4.5, and RCP8.5, for a grand total of nine scenarios, to mimic evolution of the hydrological cycle under future climate until 2100. We subsequently test the ORs under the future hydrological scenarios (at half century and end of century) and the need for reoptimization. Poly‐Hydro model when benchmarked against historical data well mimics the hydrological budget of both catchments, including the main processes of evapotranspiration and streamflows. Teaching–learning‐based optimization delivers the best performance in both reservoirs according to objective scores and is used for future operation. Our projections in Dez catchment depict decreased precipitation along the XXI century, with ?1% on average (of the nine scenarios) at half century and ?6% at the end of century, with changes in streamflows on average ?7% yearly and ?13% yearly, respectively. In Alavian, precipitation would decrease by ?10% on average at half century and ?13% at the end of century, with streamflows ?14% yearly and ?18% yearly, respectively. Under the projected future hydrology, reservoirs' operation would provide lower performance (i.e., larger lack of water) than now, especially for Alavian dam. Our results provide evidence of potentially decreasing water availability and less effective water management in water stressed areas like Northern Iran here during this century.  相似文献   

Estimating the sediment trap efficiency of intermittently dry reservoirs: lessons from the Kruger National Park,South Africa          下载免费PDF全文

Bastian Reinwarth  Edward S. Riddell  Christoph Glotzbach  Jussi Baade 《地球表面变化过程与地形》2018,43(2):463-481

The assessment of sediment yield from reservoir siltation requires knowledge of the reservoir's sediment trap efficiency (TE). Widely used approaches for the estimation of the long‐term mean TE rely on the ratio of the reservoir's storage capacity (C) to its catchment size (A) or mean annual inflow (I). These approaches have been developed from a limited number of reservoirs (N ≤ 40), most of them located in temperate climate regions. Their general applicability to reservoirs receiving highly variable runoff such as in semi‐arid areas has been questioned. Here, we examine the effect of ephemeral inflow on the TE of 10 small (≤ 280 × 10³ m³), intermittently dry reservoirs located in the Kruger National Park. Fieldwork was conducted to determine the storage capacity of the reservoir basins. The frequency and magnitude of spillage events was simulated with the daily time step Pitman rainfall–runoff model. Different runoff scenarios were established to cope with uncertainties arising from the lack of runoff records and imperfect input data. Scenarios for the relationship between water and sediment discharge were created based on sediment rating curves. Taking into account uncertainties in hydrological modelling, uncertainties of mean TE estimates, calculated from all scenarios (N = 9), are moderate, ranging from ±6 to ±11% at the 95% confidence level. By comparison, estimating TE from the storage capacity to catchment area (C/A) ratio induces high uncertainty (ranges of 35 to 65%), but this uncertainty can be confined (15 to 33%) when the latter approach is combined with hydrological modelling. Established methods relying on the storage capacity to mean annual inflow (C/I) ratio most probably lead to an overestimation of the TE for the investigated reservoirs. The approach presented here may be used instead to estimate the TE of small, intermittently dry reservoirs in semi‐arid climate regions. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Stochastic and analytical approaches for sediment accumulation in river reservoirs     

Tanju Akar 《水文科学杂志》2020,65(6):984-994

ABSTRACT

Sediment accumulation in a river reservoir is studied by stochastic time series models and analytical approach. The first-order moving average process is found the best for the suspended sediment discharge time series of the Juniata River at Newport, Pennsylvania, USA. Synthetic suspended sediment discharges are first generated with the chosen model after which analytical expressions are derived for the expected value and variance of sediment accumulation in the reservoir. The expected value and variance of the volume of sediment accumulation in the reservoir are calculated from a thousand synthetic time series each 38 years long and compared to the analytical approach. Stochastic and analytical approaches perfectly trace the observation in terms of the expected value and variability. Therefore, it is concluded that the expected value and variance of sediment accumulation in a reservoir could be estimated by analytical expressions without the cost of synthetic data generation mechanisms.  相似文献   

The geothermal formation mechanism in the Gonghe Basin: Discussion and analysis from the geological background     

《China Geology》2018,1(3):331-345

The Gonghe Basin, a Cenozoic down-warped basin, is located in the northeastern part of the Qinghai-Xizang (Tibetan) Plateau, and spread over important nodes of the transfer of multiple blocks in the central orogenic belt in the NWW direction. It is also called “Qin Kun Fork” and “Gonghe Gap”. The basin has a high heat flow value and obvious thermal anomaly. The geothermal resources are mainly hot dry rock and underground hot water. In recent years, the mechanism of geothermal formation within the basin has been controversial. On the basis of understanding the knowledge of predecessors, this paper proposes the geothermal formation mechanism of the “heat source–heat transfer–heat reservoir and caprock–thermal system” of the Gonghe Basin from the perspective of a geological background through data integration-integrated research-expert, discussion-graph, compilation-field verification and other processes: (1) Heat source: geophysical exploration and radioisotope calculations show that the heat source of heat in the basin has both the contribution of mantle and the participation of the earth’s crust, but mainly the contribution of the deep mantle. (2) Heat transfer: The petrological properties of the basin and the exposed structure position of the surface hot springs show that one transfer mode is the material of the mantle source upwells and invades from the bottom, directly injecting heat; the other is that the deep fault conducts the deep heat of the basin to the middle and lower parts of the earth’s crust, then the secondary fracture transfers the heat to the shallow part. (3) Heat reservoir and caprock: First, the convective strip-shaped heat reservoir exposed by the hot springs on the peripheral fault zone of the basin; second, the underlying hot dry rock layered heat reservoir and the upper new generation heat reservoir and caprock in the basin revealed by drilling data. (4) Thermal system: Based on the characteristics of the “heat source-heat transfer-heat reservoir and caprock”, it is preliminarily believed that the Gonghe Basin belongs to the non-magmatic heat source hydrothermal geothermal system (type II2₁) and the dry heat geothermal system (type II2₂). Its favorable structural position and special geological evolutionary history have given birth to a unique environment for the formation of the geothermal system. There may be a cumulative effect of heat accumulation in the eastern part of the basin, which is expected to become a favorable exploration area for hot dry rocks.  相似文献   

山西省地热资源及其开发利用模式探讨          下载免费PDF全文

韩颖  白雪峰  张欣 《中国地质调查》2018,5(5):13-20

山西省地热资源丰富,但分布不均,总体开发利用程度偏低,存在资源勘查研究程度低、分散开采普遍、重开采、轻回灌、创新发展研究重视不够等问题,对地热资源可持续利用不利。在山西省地热资源现状调查评价的基础上,系统总结了山西省地热资源的分布规律、主要热储类型、特征以及水热型地热资源开发利用现状,按照不同热储类型及地热资源赋存地质条件,提出地热资源开发利用模式建议,并提出在山西省打造温泉小镇的构想。  相似文献   

塔里木溢流玄武岩火山通道的三维结构及其热成因气体释放   总被引：1，自引：1，他引：0  

王磊  田伟  魏子寒  弓明月  李晓敏 《岩石学报》2018,34(1):75-90

塔里木上奥陶统-志留系沉积地层中广泛发育早二叠世溢流玄武岩的火山通道相岩床-岩墙网络。三维地震数据解释结果显示,这些火山通道以平行围岩地层的岩床和斜切围岩地层的"碟状岩床"为主要特征。在玄武岩喷发过程中,火山通道岩浆的热量可以导致沉积围岩发生热接触变质并将沉积围岩中的有机质转化为"热成因气体"。在塔北英买2井区火山通道烘烤沉积围岩模型基础上,利用有限元热模拟方法确定了该区早二叠世玄武岩喷发时火山通道热烘烤影响范围随时间的变化。基于沉积围岩有机质丰度估算,该区热烘烤成因甲烷释放量可达11.3Gt(即113亿吨)。如果整个塔里木溢流玄武岩省具有与英买2地区相同的释放强度,则塔里木溢流玄武岩省活动期间释放的甲烷总量可达7062.5Gt,必然导致非常显著的环境效应。同时,玄武岩火山通道岩浆引起的热接触变质作用对已存在的油藏具有明显的破坏作用,塔里木盆地古生界总量约8~10Gt的油藏破坏和大量沥青的形成可能与此有关。  相似文献   

Is Ziarat a Potential Site for Conventional or Unconventional Energy Resources?     

Sarfraz KHAN  Umair Bin NISAR  Khawar A. AHMED  Muhammad WASEEM  Waqas AHMED 《《地质学报》英文版》2018,92(4):1544-1557

A structural interpretation of the Ziarat block in the Balochistan region (a part of the Suleiman Fold and Thrust Belt) has been carried out using seismic and seismological data. Seismic data consists of nine 2.5D pre‐stack migrated seismic lines, whereas the seismological data covers the Fault Plane Solution and source parameters. Structural interpretation describes two broad fault sets of fore and back thrusts in the study area that have resulted in the development of pop‐up structures, accountable for the structural traps and seismicity pattern in terms of seismic hazard. Seismic interpretation includes time and depth contour maps of the Dungan Formation and Ranikot group, while seismological interpretation includes Fault Plane Solution, that is correlated with a geological and structural map of the area for the interpretation of the nature of the subsurface faults. Principal stresses are also estimated for the Ranikot group and Dungan Formation. In order to calculate anisotropic elastic properties, the parameters of the rock strength of the formations are first determined from seismic data, along with the dominant stresses (vertical, minimum horizontal, and maximum horizontal). The differential ratio of the maximum and minimum horizontal stresses is obtained to indicate optimal zones for hydraulic fracturing, and to assess the potential for geothermal energy reservoir prospect generation. The stress maps indicate high values towards the deeper part of the horizon, and low towards the shallower part, attributed to the lithological and structural variation in the area. Outcomes of structural interpretation indicate a good correlation of structure and tectonics from both seismological and seismic methods.  相似文献