Fast approximate EM induction modeling of metallic and UXO targets using a permeable prism     

Michael W. Asten  Andrew C. Duncan   《Journal of Applied Geophysics》2007,61(3-4):235-242

The time-domain EM induction response of non-magnetic and magnetic targets can be approximated using a conductive permeable prism composed of six faces of conductive plates, each face being composed of a set of conductive ribbons. The effect of magnetic permeability is included by the use of two “apparent flux gathering” coefficients, and two “effective magnetic permeability” coefficients, in the axial and transverse directions. These four magnetic property coefficients are a function of physical properties and geometry of the target, but are independent of prism orientation relative to a transmitter. The approximation algorithm is computationally fast, allowing inversions for target parameters to be achieved in seconds. The model is tested on profiles acquired with a Geonics EM63 time-domain EM metal detector over a non-magnetic copper pipe target, and a steel artillery shell in horizontal and vertical orientations. Results show that this approximation to a permeable prism has a capability of fitting geometric, conductivity and magnetic parameters at both early and late sample times. The magnetic parameters show strong change from early to late times on the EMI decay curve, indicating that the magnetic properties of the target have non-linear characteristics. It is proposed that these magnetic parameters and the nature of their non-linearity may carry additional discrimination information for distinguishing between intact munitions and scrap in UXO studies.  相似文献   

地下爆炸成腔注浆支护的小型实验研究     

冯长根  韩宝成  王丽琼 《岩土力学》2002,23(5):551-554

针对爆扩成腔稳定性差、渗水率高及遇水坍塌等问题，采用注浆抽浆法对爆炸空腔进行了支护，并进行防渗小型实验研究。确定了注浆临界水灰比为0.8:1，分别对重力注浆、压力注浆以及压力注浆加防水剂和无支护的4个空腔进行了支护对比实验。实验表明：重力注浆不足以达到要求，压力注浆是一种解决支护和防渗较为可行的方法，加入防水剂后效果更好。  相似文献   

Hg~(2+)对水鳖(Hydrocharis dubia)叶片生理生化及超微结构的毒害效应     

郝怀庆  施国新  杜开和  徐勤松 《湖泊科学》2001,(2)

研究了不同浓度Hg2 +对水鳖叶片光合放氧速率、呼吸速率、细胞膜透性、硝酸还原酶活性以及超微结构的毒害影响 .结果表明 ,随着Hg2 +浓度的增加 ,水鳖叶片的光合放氧速率逐渐下降 ,呼吸速率、硝酸还原酶活性先升后降 ,而细胞膜透性则逐渐上升 .电镜观察发现 ,水鳖叶细胞遭受Hg2 +毒害初期 ,染色质凝集 ,叶绿体中类囊体片层以及线粒体嵴突膨胀 .随着叶细胞遭受毒害程度的加深 ,核膜破裂 ,染色质与核质消失 ,叶绿体膨胀解体 ,线粒体空泡化  相似文献   

水--煤层气两相流体在煤层中的渗流规律   总被引：1，自引：1，他引：1  

张永利  邰英楼  王来贵 《地质灾害与环境保护》2001,12(4):63-66

采用煤体承受有效应力、水-气混合流动及固一流相互作用的基本原理，建立了煤层气开采过程中水-煤层气两相流渗的基本方程，通过自行设计的实验装置，测定了煤层中水-煤层气共同流动时的两相流体的流量，渗透率及随水的饱和度变化关系，并据此模拟出了反映水-煤层气渗透基本规律，从而为煤层气开采提供了理论基础。  相似文献   

Characterization of granite matrix porosity and pore-space geometry by in situ and laboratory methods   总被引：3，自引：0，他引：3  

M. Schild  S. Siegesmund  A. Vollbrecht  M. Mazurek 《Geophysical Journal International》2001,146(1):111-125

  相似文献   

The effects on seismic waves of interconnected nearly aligned cracks   总被引：1，自引：0，他引：1  

S. R. Tod 《Geophysical Journal International》2001,146(1):249-263

  相似文献   

利用相控模型进行井间参数预测   总被引：18，自引：0，他引：18  

桂峰  马正 《地球科学》2001,26(1):49-53

储层物性参数在空间的展布，一直是储层非均质性研究的难点，利用分形和蒙特卡洛方法，在精细的沉积微相及小层对比研究基础之上，预测了井间的岩石相分布，并根据取心井资料，建立了各种岩石相的渗透率相控模型，从而预测出井间渗透率的分布。该方法以地质特征为基础，将地质资料与数学方法相结合，充分体现了渗透率在井间既具有连续性，同时变化又非常剧烈的特点，为储层物性空间预测提供了新的思路。  相似文献   

Low Electrical Resistivity And Seismic Velocity At The Base Of The Upper Crust As Indicator Of Rheologically Weak Layer     

L. Vanyan  B. Tezkan  N. Palshin 《Surveys in Geophysics》2001,22(2):131-154

Conductivity models were compiled in two geological provinces with thinsediments. The first province is the margin of the Precambrian East EuropeanPlatform. The second one is the Phanerozoic Rhenish Massif as a part of CentralGermany Hercinicum. In both provinces, a conducting layer was revealed at thebase of the upper crust by the magnetotelluric soundings. Its depth is around10 km in the East European Platform and around 15 km in the Rhenish Massif.The conductance of the layer reaches a few tens of Siemens in the first provinceand is almost an order of magnitude greater in the second one.A good correlation between the conductor and a seismic wave-guide (low-velocityzone) exists at the base of the upper crust. Simultaneous decrease of both electricalresistivity and seismic velocity, suggests an increase of porosity and permeability inpresence of saline water. The depth of rheological weak layer in the PhanerozoicRhenish Massif corresponds to the commonly accepted depth of the thermallyinduced brittle/ductile transition. Contrary similar layer in the Precambrian EasternEuropean Platform is much shallower than the thermally induced transition. Somenew mechanism should be considered.  相似文献   

煤储层渗透性影响因素探讨   总被引：14，自引：0，他引：14  

唐书恒 《中国煤田地质》2001,13(1):28-30,86

依据煤层气井的试井资料，结合试验室测试数据和其它资料的分析，认为中国煤储层渗透性主要受原地应力状况的控制，其它因素对其也有一定的影响。  相似文献   

活性白云粉生产工艺及其物化性能研究   总被引：1，自引：0，他引：1  

贾建业  汤艳杰  王辅亚  王杨传  宁平  王建成  魏俊峰 《矿物学报》2001,21(3):439-442

活性白云粉（ABP）是在白云岩经过破碎、细粉碎、表面改性的基础上得到的一种新型改性功能填料。本文利用河南辉县市的拍石头和张村两地产出的白云岩作为实验原料，对其表面改性的实验方法、改性剂选择及用量、改性条件及改性效果等方面进行了一定的探讨，并且对改性前后的白云石粉体的粒度、比表面积等性能及红外光谱特征做了对比研究。生产工艺和物性测试研究表明：活性白云粉代替轻质碳酸钙作橡胶填料前景广阔；与轻钙相比，活性白云粉的粒度不够均匀，经优化和改善生产工艺条件，可望进一步提高其应用价值。  相似文献