我国深海钻探重入钻孔技术优选及设计思路          下载免费PDF全文

熊亮  谢文卫  卢秋平  朱芝同  刘晓林 《探矿工程》2020,47(7):1-7

深海钻探通常采用无隔水管开路钻进，当更换钻头或钻具，测井、处理孔内事故等情况时，需要起下钻后重新进入原钻孔，此过程称为重入钻孔。由于钻探船与海底孔口有数千米的水体相隔，受海浪和洋流作用，钻探船动荡不稳，钻杆柱摇摆不定，要想重新进入原钻孔并非易事。本文通过广泛调研，对海底基盘、声呐重入系统、水下电视重入系统及无人遥控潜水器（ROV）等目前几种常见的重入钻孔技术进行了详细介绍，对各种技术的优缺点进行了综合对比，优选了水下电视重入系统作为我国深海钻探重入钻孔技术方案，初步提出了技术设计思路，为样机研发和工艺制定奠定了基础。  相似文献   

静力触探技术在东海陆架工程勘察中的应用研究     

陈培雄  刘奎  吕小飞  李冬  王振红 《海洋学研究》2011,29(4):71-76

通过对东海大陆架海底浅表层土样的静力触探参数进行统计分析,得到该区域细砂、粘土、淤泥质土和淤泥的静力触探统计值,建立了研究海区基于静力触探参数的土类判别图,可用于快速判定土的类别.根据静力触探参数,并应用经验公式估算了海底粘性土的抗剪强度和灵敏度,对估算公式经验系数选择进行了深入研究,提出在研究海区应用经验公式进行粘性...  相似文献   

GROUND THERMAL CONDITIONS AT CHACHANI VOLCANO,SOUTHERN PERU     

NURIA ANDRÉS  DAVID PALACIOS  JOSE ÚBEDA  JESÚS ALCALÁ 《Geografiska Annaler: Series A, Physical Geography》2011,93(3):151-162

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Dynamics of volcanic eruptions: Understanding electric signatures for activity monitoring     

《Comptes Rendus Geoscience》2015,347(3):112-123

Aside common methods as seismology, ground deformation, and geochemistry, electromagnetic and especially electric ones can efficiently be applied for imaging and monitoring active volcanoes and hydrothermal systems that most often control the initial eruptive phase. Surveys and mappings image ground fluids flow, faults systems, and structural interfaces with anomalies up to several hundred of mV. Reiteration of surveys highlights time and spatial evolution. Continuous networks must extend surveys when the activity becomes stronger. Resolution in the data can reach a few microvolts as compared to the tens of millivolts for surveys. Observations made on several volcanoes definitively show that electric signals, up to some tens of millivolts, may appear some hours to a few weeks before ground deformation and seismicity, and are related to some extent to the location of the future activity. These transient signals may have a relationship with those recorded aboard satellites. Both of them appear during the transition period between the “fatigue” and the “dynamical” stages, which announces accelerating and irreversible processes.  相似文献   

Geochemical Features of the Hubin Spring Gases from the Northern Caldera Lake of the Tianchi Volcano,Changbai Mountains     

Gao Ling~  Shangguan Zhiguan~  Wei Haiquan~  Zhao Ciping~ 《中国地震研究》2011,25(3):370-377

This paper deals with geochemical features of gas emitted from the Hubin Springs.The Hubin Springs zone,a strong thermal emission zone,is are locatedd at the north edge of the Tianchi caldera lake.Very young deposits with uncertain eruption date are found on the top area of the Tianwenfeng,which might have been formed in one of the recent eruptions or the Millennium Eruption.It is of significance to study the geochemistry features of the emitting gas from the Hubin Springs to understand the activities of the Tianchi Volcano.This paper systematically sampled and analyzed the gases emitted from the Hubin Springs and discussed their geochemistry features.The results show that there is a high content of deep derived gases,such as CO2,He,CH4 and Ar in Hubin Springs zone.The isotopic ratio of He lies between 4.18 and 5.95 Ra.The averaged mantle derived gas content calculated from the 4He/20Ne ratio and He content reaches 67.1%.All these show that the Hubin Springs are located on a special belt of deep gases released in high intensity and large scale.The spatial distribution of Helium isotope is characterized by concavity,showing that this special area may be related to the volcanic edifice.It is highly possible that the released gases represent the residual gas samples of the latest eruptions from the Tianchi Volcano.However more detailed studies are demanded.  相似文献   

绳索取心深孔偏心楔同径侧钻绕障技术实践          下载免费PDF全文

王红阳  罗永贵  腾新明 《探矿工程》2015,42(6):17-20

招远市栾家河金矿区 47ZK3孔设计孔深2570 m,于孔深2297 m处发生跑钻事故,处理至孔内事故底部时,处理难度增大。为加快事故处理进度,降低事故损失,采用偏心楔侧钻技术进行同径造斜的方法,绕开事故段。通过对偏心楔设计、偏心楔制作与安装、造斜钻头及分支钻进钻头选择等技术措施进行优化,较好地解决了偏心楔侧钻过程中偏心楔固定及过斜面工序的关键技术问题,顺利地将分支孔延伸至终孔。  相似文献   

几种降低锥束CT辐射剂量的方法          下载免费PDF全文

陈云斌  王远  刘清华 《CT理论与应用研究》2017,26(3):327-334

千伏级锥束CT在放射治疗、外科手术、口腔疾病诊断等领域都有广泛的应用。然而,频繁地使用千伏级锥束CT,也会给患者甚至医生带来额外的射线辐射损伤。相关统计结果表明,X射线辐射能够诱发癌症,特别是儿童和女性对射线辐射异常敏感。因此,合理使用锥束CT,同时降低锥束CT辐射剂量,对于降低射线辐射并发症风险显得非常重要。本文总结了降低锥束CT辐射剂量的常用措施,包括降低管电流、局部扫描、脉冲扫描、短扫描以及少投影扫描。辐射剂量的降低有可能会在重建图像中引入噪声、伪影。针对特定的问题,本文也提出了对应的补偿方法。   相似文献   

Effect of Penetration Rates on the Piezocone Penetration Test in the Yellow River Delta Silt     

ZHANG Jiarui  MENG Qingsheng  ZHANG Yan  FENG Xiuli  WEI Guanli  SU Xiuting  LIU Tao 《中国海洋大学学报(英文版)》2022,21(2):361-374

Partial drainage often occurs during piezocone penetration testing on Yellow River Delta silt because of its intermediate physical and mechanical properties between those of sand and clay.Yet,there is no accurate understanding for the range of penetra-tion rates to trigger the partial drainage of silt soils.In order to fully investigate cone penetration rate effects under partial drainage condi-tions,indoor 1 g penetration model tests and numerical simulations of cavity expansion at variable penetration rates were carried out on the Yellow River Delta silt.The boundary effect of the model tests and the variation of key parameters at the different cavity ex-pansion rates were analyzed.The 1 g penetration model test results and numerical simulations results consistently indicated that the penetration rate to trigger the partially drainage of typical silt varied at least three orders of magnitude.The numerical simulations also provide the reference values for the penetration resistance corresponding to zero dilation and zero viscosity at any given normalized penetration rate for silt in Yellow River Delta.These geotechnical properties can be used for the design of offshore platforms in Yel-low River Delta,and the understanding of cone penetration rate effects under the partially drained conditions would provide some technical support for geohazard evaluation of offshore platforms.  相似文献   

冲绳海槽中西部边缘区沉积物成因和沉积环境     

高素兰  王慧艳  辛春英 《海洋科学进展》1998,(3)

本文根据１９９６年“中－法合作东海计划”在冲绳海槽中西部边缘区所取柱状样岩芯沉积物粒度分析资料,对该区沉积物特征进行研究。结果表明,火山沉积和富含生物的半远洋深海软泥沉积是本区的主要特征。以４８１ｃｍ为界,上、下两层沉积物截然不同,可能是沉积物的来源不同或者是水动力条件的差异。该区主要受火山活动的影响,其次是黑潮、大洋风暴  相似文献   

Non-Simultaneous Failure of Ice in Front of Multi-Leg Structures   总被引：4，自引：1，他引：4  

SHI  Qingzeng 《中国海洋工程》2002,16(2):183-192

Because the multi-leg jacket structure is the major type of offshore structures in the Bohai Sea, the study of non-si-multaneous failure of i鏴 on multi-leg structures is important. However, the non-simultaneous failure has not been consid-ered in engineering design until now, obviously resulting in costly design and notable waste. To resolve this problem, this paper, by means of analysis of experimental data, calculates the coefficient of the non-simultaneous failure for the double-pile structure, the square four-leg structure, the single-line multi-pile structure, and the conical structure, respectively, and provides some reference criteria for engineering design.  相似文献