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Influence of tool
eccentricity in a well casing on theultrasonic
televiewer image and its correction processing 下载免费PDF全文
《应用声学》1999,18(2):2
文章研究了在套管井中仪器偏心对井壁超声电视图象的影响,提出了基于计算影响所用模型的校正方法。实验结果表明,该方法能较好地消除由于仪器偏心所引起的超声电视图象中的两条垂直黑带,明显地改善图象的质量。经对比度增强后,井壁的细节更加清楚。 相似文献
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本文在声波水泥胶结质量测井中根据声等效衰减系数的概念和一种采用双发双收原理进行声幅补偿来判断套管井水泥胶结质量的方法。作者根据这种概念和方法建立了实验装置,进行了室内试验和声波幅度的数据测量。这种装置大大减小井下仪器在油井中的倾斜偏心,声波换能器的发射,接收灵敏度和井壁透射系数等因素对接收的声波幅度的影响,和目前国产的水泥胶结质量声波测井仪器相比较,提高了声波幅度的测量准确性,从而也就提高了水泥胶结质量声波测井的可靠性。 相似文献
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目前在油田的实际应用中,声幅-变密度水泥胶结测井(CBL/VDL)在套管井的水泥胶结质量评价中发挥重要作用。但是,在一些大斜度井或者水平井中,往往由于仪器或者套管的重量等原因导致套管井中出现偏心现象,这给利用声波测井资料进行水泥胶结质量评价带来一些难题。为此,本文建立了套管偏心和仪器偏心两种情况下的三维声学模型,利用柱坐标系下的三维交错网格有限差分算法数值模拟了两种偏心情况下的声波传播情况,并着重研究了偏心率的变化对套管井中声场波形特征,尤其是套管波及地层波特征的影响。另外,模拟了具有不同外径尺寸的套管和偏心率的组合情况下的声场传播情况,在此基础上研究了偏心率的大小对声场特征的影响规律。本文的研究结果表明,套管偏心和仪器偏心均会给声场波形特征带来影响,且随着偏心率的增加而增大;相比较而言,仪器偏心对套管波的影响更大。 相似文献
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总装调对心干涉仪的设计与测量精度分析 总被引:4,自引:1,他引:3
为了满足大口径光学系统各分立元件的高精度对心要求 ,设计制造了总装调对心干涉仪。介绍了仪器的工作原理及关键结构工艺 ,并对影响偏心测量的因素进行了讨论。仪器的测量精度同被测镜的曲率半径及两测量点的间距有关。当被测镜的曲率半径小于 1.5 m、两测量点的间距为 5 0 0 mm时 ,其偏心测量精度小于 1μm,仪器的测量偏心角度的最小格值达 0 .12 相似文献
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提出了一种可用于随钻声波测井的非对称的圆弧片状声源,旨在发展一种能够在钻井过程中精确确定反射体位置的三维反射声波远探测方法。研究了在复杂的井孔条件(钻铤偏心、各向异性和不规则井孔形状)下,该声源向地层中辐射的声场的特征,进一步分析了不同井况条件对三维随钻远探测声波测井的影响。数值模拟结果表明,在圆形井孔、钻铤居中条件下,无论快速地层还是慢速地层,圆弧片状声源均能够向地层中定向辐射声波信号,其辐射指向性图主瓣3 dB角宽窄,旁瓣级低,方位分辨率较高,适用于随钻三维反射成像测井;井壁粗糙程度、地层各向异性等因素对声场特征影响不大,说明该方法适用于粗糙井壁和各向异性地层情况;钻铤偏心和井壁一侧的破坏对辐射声场的影响较大。对本文的模型而言,在破坏深度小于3 cm或者偏心距离小于2 cm时,声场仍有较好的方位特征,该方法仍然适用。而当破坏深度大于6 cm,声场指向性图出现多个幅值较大的角瓣,可能无法利用其确定反射体的方位。本文的研究结果为三维随钻反射声波仪的设计和研发提供了必备的理论基础。 相似文献
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本文讨论以高速电视图象为对象的数据压缩技术,论述采用流水线法对图象数据实施变表游程长度编码,满足高速电视图象数据压缩实时,高速,无损的要求,并进行了实验验证。 相似文献
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为满足扫描成像系统对图象配准精度,从理论上分析了在等时间采样方式下,遥感仪器对扫描系统速度稳定度的要求.探讨了等角度这一新型采样方式应用于未来遥感仪器的可行性.并将这两种采样方式成功应用于自行研制的短波红外成像仪.扫描图象表明等角度采样可以避免等时采样所产生的图象畸变. 相似文献
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平面研磨加工中工件转速的理论分析 总被引:1,自引:0,他引:1
平面研磨加工中工件转速决定了磨具与工件间的相对运动速度分布,并进而影响磨具和工件的面形精度。在考虑了磨具上金刚石丸片的实际排列以及接触区压强的实际分布的前提下,运用力学和运动学的方法,模拟分析了在固着磨料平面研磨加工中镜盘所受的摩擦力矩。在此基础上,根据稳定加工时力矩平衡原理得出了包含转速的数学公式,并重点探讨了工件半径和偏心矩对工件转速的影响。结果表明,工件转速并不总是等于磨具转速,而是随着偏心矩的增大而逐渐增高,随着工件半径的变化发生起伏波动。 相似文献
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David Pardo Pawel Matuszyk Ignacio Muga Carlos Torres-Verdín Angel Mora Victor M. Calo 《Journal of computational physics》2011,230(16):6320-6333
The paper introduces a high-order, adaptive finite-element method for simulation of sonic measurements acquired with borehole-eccentered logging instruments. The resulting frequency-domain based algorithm combines a Fourier series expansion in one spatial dimension with a two-dimensional high-order adaptive finite-element method (FEM), and incorporates a perfectly matched layer (PML) for truncation of the computational domain. The simulation method was verified for various model problems, including a comparison to a semi-analytical solution developed specifically for this purpose. Numerical results indicate that for a wireline sonic tool operating in a fast formation, the main propagation modes are insensitive to the distance from the center of the tool to the center of the borehole (eccentricity distance). However, new flexural modes arise with an increase in eccentricity distance. In soft formations, we identify a new dipole tool mode which arises as a result of tool eccentricity. 相似文献
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Gravitational radiation of binary systems can be studied by using the adiabatic approximation in General Relativity. In this
approach a small astrophysical object follows a trajectory consisting of a chained series of bounded geodesics (orbits) in
the outer region of a Kerr Black Hole, representing the space time created by a bigger object. In our paper, we study the
entire class of orbits, both of constant radius (spherical orbits), as well as non-null eccentricity orbits, showing a number
of properties on the physical parameters and trajectories. The main result is the determination of the geometrical locus of
all the orbits in the space of physical parameters in Kerr space–time. This becomes a powerful tool to know if different orbits
can be connected by a continuous change of their physical parameters. A discussion on the influence of different values of
the angular momentum of the hole is given. Main results have been obtained by analytical methods. 相似文献
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Machine vision systems are used in many areas for monitoring of technological processes. Among this processes welding takes important place, where often infrared cameras are used. Besides reliable hardware, successful application of vision systems requires suitable software based on proper algorithms. One of most important group of image processing algorithms is connected to image segmentation. Obtainment of exact boundary of an object that changes shape in time, such as the welding arc, represented on a thermogram is not a trivial task. In the paper a segmentation method using supervised approach based on a cellular neural networks is presented. Simulated annealing and genetic algorithm were used for training of the network (template optimization). Comparison of proposed method to a well elaborated segmentation method based on region growing approach was made. Obtained results prove that the cellular neural network can be a valuable tool for infrared welding pool images segmentation. 相似文献
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