Scattering of water waves by a pair of vertical porous plates     

R. Gayen  Arpita Mondal 《地球物理与天体物理流体动力学》2015,109(5):480-496

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热弹性P波在有流体夹层介质中的传播问题及其基本特征^*     

张艳芳  张丽娟  武晔  张新超  李瑞东  胡顺田  熊仲华  赵永安 《地震》2016,36(2):76-84

本文作为基础理论研究,讨论了热弹性P波在有流体夹层介质中的传播问题。研究结果表明:热弹性波在流体夹层的传播中,不仅存在反射波、透射波,而且,还伴随有具有相同传播速度的温度波;且其反射系数、透射系数均为复数,并与介质的物性参数及夹层厚度有关。同时指出反射波、透射波的振幅、位相均受介质的物性参数及夹层厚度的影响。此外,还表明夹层中往返震荡的层间波是一系列正传热弹性波和反传热弹性波的叠加。  相似文献   

利用井中低频偶极横波进行声波远探测的新方法   总被引：2，自引：1，他引：1       下载免费PDF全文

魏周拓  唐晓明  苏远大  谭宝 《地球物理学报》2013,56(10):3572-3580

为了突破目前声波远探测技术存在的局限性,提出了一种新的偶极横波远探测方法,即利用井中偶极子产生的井中弯曲波存在低频截止频率的现象,在声源截止频率以下激发偶极声波.通过对比分析井中偶极声源分别在截止频率上、下激发时,井孔内外产生的辐射声场,明确了截止频率以下井中偶极声源的远场辐射特征和低频截止频率激发偶极横波的优势,结合数值模拟,进一步对其反射声场进行了分析.结果表明,该方法可以避免艾里相的巨大振幅对数据量化产生的"饱和"效应,相比传统的远探测测井方式更具优势,常规源距即可满足专门的远探测测井仪器需求.  相似文献   

Water‐bottom multiple attenuation by Kirchhoff extrapolation     

Emmanuel Spadavecchia  Vincenzo Lipari  Nicola Bienati  Giuseppe Drufuca 《Geophysical Prospecting》2013,61(4):725-734

Despite being less general than 3D surface‐related multiple elimination (3D‐SRME), multiple prediction based on wavefield extrapolation can still be of interest, because it is less CPU and I/O demanding than 3D‐SRME and moreover it does not require any prior data regularization. Here we propose a fast implementation of water‐bottom multiple prediction that uses the Kirchhoff formulation of wavefield extrapolation. With wavefield extrapolation multiple prediction is usually obtained through the cascade of two extrapolation steps. Actually by applying the Fermat’s principle (i.e., minimum reflection traveltime) we show that the cascade of two operators can be replaced by a single approximated extrapolation step. The approximation holds as long as the water bottom is not too complex. Indeed the proposed approach has proved to work well on synthetic and field data when the water bottom is such that wavefront triplications are negligible, as happens in many practical situations.  相似文献   

三维地震勘探技术在新疆沙吉海井田中的应用     

王平  李丽萍  马小平  杨森  汪鸿  张炜 《新疆地质》2012,30(3):355-358

针对沙吉海井田以往未开展过地震勘探,煤层多、局部间距小特点,介绍了研究区主要地震反射波与煤层对应关系.通过对T13、T12、T10、T6反射波研究,采用地震波阻抗反演技术对该区煤层厚度及煤层结构进行解释,查明井田构造形态和主要煤层赋存变化特征,取得了较好地震勘探效果.  相似文献   

Separation of obliquely incident and reflected irregular waves by the Morlet wavelet transform   总被引：1，自引：0，他引：1  

Yuxiang Ma  Guohai Dong  Xiaozhou Ma 《Coastal Engineering》2011

An existing 2D time-domain method for separating irregular incident and reflected waves by wavelet transform [Ma et al., 2010. A new method for separation of 2D incident and reflected waves by the Morlet wavelet transform. Coastal Eng., 57(6):597–603] is extended to account for obliquely incident irregular waves propagating over sloping bottoms. The linear shoaling and refraction coefficients are adopted to determine the amplitude and phase changes of waves. The optimal central frequency of the Morlet wavelet is determined by the minimum Shannon wavelet entropy. Numerical tests show that the present method can accurately separate waves over horizontal depths. For waves at sloping bottoms, however, the separation errors increase as bottom slope increases and are significant for waves with incident angle larger than π/3.  相似文献   

基于等效Thomsen参数的P-SV波AVO属性研究   总被引：1，自引：1，他引：0       下载免费PDF全文

刘前坤  韩立国  廉玉广  王恩利 《地震工程学报》2008,30(3):214-220,305

在等效Thomsen各向异性参数的P-SV波反射系数近似公式基础上研究了反射系数的多种AVO(振幅随炮检距变化)属性特征,针对不同的属性特征构建了多属性AVO交绘图;并利用反射系数公式对三类含气砂岩AVO的特征进行分析.结果表明P-SV波反射系数公式可以有效的区分第三类含气砂岩;岩石的孔隙度、流体饱和度等信息是影响地震波AVO的重要因素.利用Gassmann方程进行了对上层为HTI介质,下层为孔隙储层的介质模型进行了流体替换计算,分析了孔隙度、含气饱和度和各向异性参数变化对地层AVO的影响.  相似文献   

Interaction of ocean waves with floating and submerged horizontal flexible structures in three-dimensions     

《Applied Ocean Research》2019

A three-dimensional general mathematical hydroelastic model dealing with the problem of wave interaction with a floating and a submerged flexible structure is developed based on small amplitude wave theory and linear structural response. The horizontal floating and submerged flexible structures are modelled with a thin plate theory. The linearized long wave equations based on shallow water approximations are derived and results are compared. Three-dimensional Green’s functions are derived using fundamental source potentials in water of finite and infinite depths. The expansion formulae associated with orthogonal mode-coupling relations are derived based on the application of Fourier transform in finite and infinite depths in case of finite width in three-dimensions. The usefulness of the expansion formula is demonstrated by analysing a physical problem of surface gravity wave interaction with a moored finite floating elastic plate in the presence of a finite submerged flexible membrane in three-dimensions. The numerical accuracy of the method is demonstrated by computing the complex values of reflected wave amplitudes for different modes of oscillation and mooring stiffness. Further, the effect of compressive force and modes of oscillations on a free oscillation hydroelastic waves in a closed channel of finite width and length for floating and submerged elastic plate system is analysed.  相似文献   

Conserved quantities and the inverse problem of reflection seismology     

Ian Lerche 《Pure and Applied Geophysics》1990,132(3):583-597

We show that the time-dependent wave equation in both one and two spatial dimensions possesses quantities which are globally conserved. We show how these conserved quantities can be used to determine the characteristic impedance, the rock density and the elastic constant of the rock. We also demonstrate that the conserved quantities possess the capability of determining and/or bracketing the unknown component of the direct pressure response, which is required to begin downward continuation algorithms. Further, we demonstrate that the conserved quantities are always available irrespective of the source structure in time. Numerical instability, arising if the filtering due to the source structure is too harsh, can then be controlled to a degree by demanding that the conserved quantities be indeed conserved.  相似文献   

New insights into the crustal structure of the North German Basin from reprocessing of seismic reflection data using the Common Reflection Surface stack   总被引：1，自引：0，他引：1  

Mi-Kyung Yoon  Mikhail Baykulov  Stefan Dümmong  Heinz-Jürgen Brink  Dirk Gajewski 《International Journal of Earth Sciences》2008,97(5):887-898

The influence of deep crustal processes on basin formation and evolution and its relation to current morphology is not well understood yet. A key feature to unravel these issues is a detailed seismic image of the crust. A part of the data recorded by the hydrocarbon industry in the late 1970s and 1980s in the North German Basin were released to the public recently. The seismic reflection data were recorded down to 15 s two-way travel time. The mean Common Midpoint fold of about 20 is relatively low compared to contemporary seismic acquisitions. The processing of the 1980s focussed on the sedimentary structures to explore the hydrocarbon potential of this area. We applied the Common Reflection Surface stack technique to the data sets, which is well suited for low-fold data. The reprocessing was focussed on the imaging of the subsedimentary crustal range. The reprocessed images show enhanced reflections, especially in the mid and lower crustal part. Also, the image of the salt structures in the graben area was improved. Furthermore, the reprocessed images indicate an almost flat Moho topography in the area of the Glückstadt Graben and an additional lower crustal structure, which can be correlated with a high-density body found in recent gravity modeling studies.  相似文献