裸眼井中弹性波传播的非对称模式的数值研究   总被引：6，自引：0，他引：6       下载免费PDF全文

张金钟  郑传汉 《地球物理学报》1988,31(4):464-470

本文从数值上研究了裸眼井中弹性波传播的非对称模式,给出了合成微地震图和导波（弯曲波）的频散曲线,发现在“硬”地层和“软”地层的井中,导波都是高度频散的,其最大相速度等于地层的横波速度,其截止频率低于对称模式的伪瑞利波的截止频率;在低频（2-3kHz）和长源距（3-4m）的条件下,由非对称的声源（如声偶极子）所产生的微地震图中,初至信号是以横波速度传播的,而以纵波速度传播的信号被抑制。本文的结果对研制横波速度测井仪是有意义的。  相似文献   

测井数据采集处理系统的高分辨率图像显示     

贺利洁  宋宇澄 《吉林大学学报(地球科学版)》1988,(1)

测井数据采集处理系统的高分辨率图像显示器是对测井全过程,实时监视,完成计算机控制,人—机对话方式工作,并且进行汉字图头,刻度功能,还可以回放测井过程的任意井段的参数曲线。本文主要阐述高分辨率图像显示器示技术性能及组成。  相似文献   

A remote sensing contribution to hydrologic modelling in arid and inaccessible watersheds,Pishin Lora basin,Pakistan     

Z. Sagintayev  M. Sultan  S. D. Khan  S. A. Khan  K. Mahmood  E. Yan  A. Milewski  P. Marsala 《水文研究》2012,26(1):85-99

The lack of adequate field measurements often hampers the construction and calibration of rainfall‐runoff models over many of the world's watersheds. We adopted methodologies that rely heavily on readily available remote sensing datasets as viable alternatives for assessing, managing, and modelling of such remote and inadequately gauged regions. The Soil and Water Assessment Tool was selected for continuous (1998–2005) rainfall‐runoff modelling of one such area, the northeast part of the Pishin Lora basin (NEPL). Input to the model included satellite‐based Tropical Rainfall Measuring Mission precipitation data, and modelled runoff was calibrated against satellite‐based observations, the latter included: (i) monthly estimates of the water volumes impounded by the Khushdil Khan (latitude 30°40′N, longitude 67°40′E), and the Kara Lora (latitude 30°34′N, longitude 66°52′E) reservoirs, and (ii) inferred wet versus dry conditions in streams across the NEPL. Calibrations were also conducted against observed flow reported from the Burj Aziz Khan station at the NEPL outlet (latitude 30°20′N; longitude 66°35′E). Model simulations indicate that (i) average annual precipitation (1998–2005), runoff and recharge in the NEPL are 1300 × 10⁶ m³, 148 × 10⁶ m³, and 361 × 10⁶ m³, respectively; (ii) within the NEPL watershed, precipitation and runoff are high for the northeast (precipitation: 194 mm/year; runoff: 38 × 10⁶ m³/year) and northwest (134 mm/year; 26 × 10⁶ m³/year) basins compared to the southern basin (124 mm/year; 8 × 10⁶ m³/year); and (3) construction of delay action dams in the northeast and northwest basins could increase recharge from 361 × 10⁶ m³/year up to 432 × 10⁶ m³/year and achieve sustainable extraction. The adopted methodologies are not a substitute for traditional approaches, but they could provide first‐order estimates for rainfall, runoff, and recharge in the arid and semi‐arid parts of the world that are inaccessible and/or lack adequate coverage with field data. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Fishing capacity management in Taiwan: Experiences and prospects     

Hsiang-Wen Huang  Ching-Ta Chuang 《Marine Policy》2010

Taiwan has developed its fisheries since the 1950s and become one of the major fishing nations in the high seas. Facing overcapacity and strong criticism by related Regional Fisheries Management Organizations, Taiwan did not only formulate lots of regulations to limit fishing capacity, but also spent around US$350 million from 1991 to 2008 to scrap 30% capacity of large scale longline fishing vessels and 18% of coastal fishing vessels. This study provides the insight that efficient use of budget and communication with fisherman, and coping with comprehensive stock assessment, would be the key issues in establishing a successful fishing capacity management.  相似文献   

Dive tourism, fishing and marine protected areas in the Calamianes Islands, Philippines     

Michael Fabinyi   《Marine Policy》2008,32(6):898-904

Many conservationists and local governments in the Philippines (and other tropical countries) have attempted to link marine protected areas (MPAs) with dive tourism, arguing that the user fees generated by dive tourism can potentially generate satisfactory outcomes for all stakeholders. In this paper, an account of the relationship between MPAs, dive tourism and small-scale fisheries in the Calamianes Islands, Philippines, is presented. It is argued that although the assumed harmonious relationship between marine conservation and dive tourism may work in theory, in practice different understandings of MPAs can create conflict.  相似文献   

Fishing capacity management in China: Theoretic and practical perspectives   总被引：1，自引：0，他引：1  

Huiguo Yu  Yunjun Yu 《Marine Policy》2008

The Food and Agriculture Organization (FAO) Committee on Fisheries (COFI) adopted an International Plan of Action for the Management of Fishing Capacity, which calls for all member states to achieve efficient, equitable and transparent management of fishing capacity by 2005. Based on the theoretical review of fishing capacity management, this paper examines the major practices made by China's government in managing the fishing capacity of its marine capture fisheries. Finally, it categorizes the main practices and then analyses and evaluates their effects.  相似文献   

Simulation of front end loader bucket–soil interaction using discrete element method     

Erfan G. Nezami  Youssef M. A. Hashash  Dawei Zhao  Jamshid Ghaboussi 《国际地质力学数值与分析法杂志》2007,31(9):1147-1162

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CFD 在保真取心钻具结构优化设计中的应用   总被引：1，自引：0，他引：1  

胡郁乐 《地质与勘探》2009,45(5):627-628

在无胶结、松散、易碎地层中钻进取心,采取率不足一直是困扰钻探界人士的技术难题。针对一套自行设计的高保真取心钻具,用计算流体动力学(Computational Fluid Dynamics简称CFD)方法,对钻具内的流场进行了三维数值模拟,并在此基础上对其结构进行了优化设计。事实证明,利用计算流体动力学技术对钻具的水力结构进行优化设计是一种经济而有效的手段。  相似文献   

哈萨克斯坦KKM油田钻具强稳降振提速技术研究          下载免费PDF全文

赵全民 《探矿工程》2019,46(5):34-38

KKM油田下部砂泥岩互层非均质性强导致井下钻具振动剧烈、PDC切削齿寿命低,且井眼易偏斜。目前在用PDC钻头多采用5刀翼或6刀翼16 mm切削齿以降低井下振动保证PDC钻头寿命,但降低了钻头攻击性导致机械钻速较低。针对KKM油田下部地层特点,优选了4刀翼19 mm复合片PDC钻头。该钻头具有较高的破岩效率和攻击性,可大幅度提高机械钻速;同时通过底部钻具组合动力学分析,优化形成了双稳定器+单稳单弯（0.5°）钻具组合,3个稳定器串联具有较强的稳定降振作用,配合小弯角螺杆钻进可有效提高防斜能力,降低了井下振动,配合大尺寸聚晶金刚石复合片PDC钻头实现了三开井段一趟钻完成的目标,机械钻速提高115.35%。  相似文献   

底板梳状钻孔在碎软煤层瓦斯治理中的应用          下载免费PDF全文

徐书荣  刘飞  梁道富  代茂  曹建明 《探矿工程》2019,46(7):45-50

针对碎软煤层顺层钻孔成孔深度浅、成孔率低、存在抽采盲区等突出问题,基于贵州省青龙煤矿煤层及顶底板岩层赋存特征,提出利用底板梳状钻孔进行碎软煤层长距离、区域瓦斯抽采与治理。首先分析了底板梳状钻孔的施工工艺原理及技术优势所在,从布孔层位、分支点位和钻孔间距的选择等方面总结了底板梳状钻孔的设计原则。通过钻进装备的优选、钻进工艺参数和钻具组合的优化,成功穿越破碎煤岩层孔段,并实现了127 mm套管全程护孔下放,在21605底抽巷施工完成了多组底板梳状定向钻孔。瓦斯抽采效果表明：底板梳状定向钻孔瓦斯抽采流量大、浓度高、衰减速度慢,单孔瓦斯抽采浓度60%～85%、抽采纯量08～25 m3/min,实现了碎软煤层瓦斯高效抽采。为碎软煤层矿井区域瓦斯抽采与治理提供了重要的借鉴。  相似文献