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Amplitude variation with offset and azimuth inversion to predict and evaluate coal seam fracture parameters

Frontiers of Earth Science 2023年第2期17卷 505-513页

作者： Haibo WU Shujie ZHU Qinjie LIU Shouhua DONG Yanhui HUANG Pingsong ZHANG School of Earth and Environment Anhui University of Science and TechnologyHuainan 232001China Institute of Energy Hefei Comprehensive National Science Center(Anhui Energy Laboratory)Hefei 230051China Xi’an Research Institute China Coal Technology&Engineering GroupXi’an 710076China School of Resources and Geosciences China University of Mining and TechnologyXuzhou 221116China State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing 102249China

Amplitude variation with offset and azimuth(AVOA)inversion is a mainstream method for predicting and evaluating fracture parameters of conventional oil and gas ***,its application to coal seams is limited because of the specificity of the equivalent media model for coal—also,the traditional seismic acquisition system employed in coal fields falls within a narrow *** this study,we initially derived a P‒P wave reflection coefficient approximation formula for coal seams,which is directly expressed in terms of fracture parameters using the Schoenberg linear-slide model and Hudson *** analyzed the P‒P wave reflection coefficient’s response to the fracture parameters using a two-layer forward ***,we designed a twostep inversion workflow for AVOA inversion of the fracture ***,high-density wide-azimuth pre-stack 3D seismic data were utilized for inverting the fracture density and strike of the target coal *** inversion accuracy was constrained by Student’s tdistribution *** analysis and validation of the inversion results revealed that the relative fracture density corresponds to fault locations,with the strike of the fractures and faults mainly at 0°.Therefore,the AVOA inversion method and technical workflow proposed here can be used to efficiently predict and evaluate fracture parameters of coal seams.

关键词： equivalent media model fracture density and strike azimuth Student’s t-distribution

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Binaurality and azimuth tuning of neurons in the auditory cortex of the big brown bat

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Chinese Science Bulletin 2002年第12期47卷 1024-1027页

作者： SHEN Junxian & CHEN QicaiCenter for Brain and Cognitive Science, Laboratory of Visual Information Processing, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China Department of Biology, Central China Normal University, Wuhan 430070, Center for Brain and Cognitive Science Laboratory of Visual Information Processing Institute of Biophysics Chinese Academy of Sciences Beijing China Department of Biology Central China Normal University Wuhan China

By using a combined closed and free-field stimulation system, binaurality and azimuth tuning of the neurons in the auditory cortex of the big brown bat, Epte-sicus fuscus, were studied. A variety of azimuth-tuning functions were demonstrated for the binaural neurons. The large majority of EE (contralateral and ipsilateral excitatory) neurons exhibited azimuth selectivity with the best azimuths (BA) at contralateral 30°-40°, some at ipsilateral 20°-40° and preferred azimuth ranges (PAR, response amplitude >75% of maximum) between 8° and 40°. Sound source azimuths strongly modulate spike counts with a mean modulation depth of 83.8% for EE neurons. EI (contralateral excitatory and ipsilateral inhibitory) neurons have simple azimuth tuning with BA located at contralateral 20°-40° and a broad PAR ranged from 30° to 55°. The present results suggest that azimuth-tuning characteristics of binaural neurons in the auditory cortex of the bat are of significance for acoustic behaviour.

关键词： bat auditory cortex binaural neurons azimuth tuning.

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Estimation of azimuth and slowness of teleseismic signals recorded by a local seismic network

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Acta Seismologica Sinica(English Edition) 2002年第6期15卷 646-655页

作者： JIN Ping(靳平) PAN Chang-zhou(潘常周) Northwest Institute of Nuclear Technology Xian 710024 China Northwest Institute of Nuclear Technology Xian 710024 China

A new method that is applicable to local seismic networks to estimate the azimuth and slowness of teleseismic signals is introduced in the paper. The method is based on the correlation between the arrival times and station positions. The analyzed results indicate that the azimuth and slowness of teleseismic signals can be accurately estimated by the method. Average errors for azimuth and slowness measurements obtained by this method using data of Xian Digital Telemetry Seismic Network are 2.0?and 0.34 s/(?, respectively. The conclusions drawn from this study indicate that this method may be very useful to interpret teleseismic records of local seismic networks.

关键词： local station network teleseismic event azimuth slowness

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An Error Modeling Framework for the Sun azimuth Obtained at a Location with the Hour Angle Method

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Positioning 2012年第2期3卷 21-29页

作者： Tarig A. Ali Department of Civil Engineering American University of Sharjah Sharjah United Arab Emirates.

Sun observations provide a robust way for determining the geodetic or true azimuth at a location. azimuth is generally defined as the angle in the plane measured from the meridian’s north (or south) to the location of the line of interest. It is common to use the north azimuth;also referred to as “azimuth”, especially in civilian surveying applications. The astronomic meridian is obtained through astronomic observations of the Sun or North Star (Polaris) and it is important since it provides one instance of the geodetic or true meridian. There are two methods for determining the sun azimuth;the first is known as the hour angle method and the other is called the altitude method. The hour angle method requires the determination of accurate time while altitude method requires accurate vertical angle. The hour angle method is more popular because it is more accurate, can be performed at any time of day and is applicable to the sun, Polaris and other stars. In this article, an error modeling framework for the errors result in the process of determining the sun azimuth using the hour angle method;namely random errors, is presented. A Gauss-Markov model is used to represent the errors in the true azimuth estimation process. Six sets of sun observation for azimuth data;three with telescope direct and three reverse, including horizontal circle’s readings and time were collected and used in order to estimate the true azimuth of a line in a study area in central Orlando, Florida, United States.

关键词： True azimuth Astronomic Meridian Hour Angle

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Fault Identification Based on Wide-azimuth Seismic Data: A Case Study in the Bohai Bay

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Journal of Geoscience and Environment Protection 2019年第5期7卷 294-299页

作者： Sian Zhu Hongtao Chen Yongjun Hu Yubin Feng Chunzhi Zhang Dagang Branch BGP CNPC Tianjin China

Full-azimuth common reflection-angle gathers could be stacked at any azimuth. The stacked data at the azimuth perpendicular to fractures exhibit the largest azimuthal anisotropy, while the stacked data at the azimuth parallel to fractures exhibit the smallest azimuthal anisotropy. In petroleum exploration in Block A, a neritic province in the Bohai Bay, we use the stacked data at the azimuth perpendicular to fractures to improve fault interpretation. We also use attribute fusion to identify fractures in different directions.

关键词： Wide azimuth Fault Identification azimuth Stack Bohai Bay Basin azimuth Fusion

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Three Median Relations of Target azimuth in one Dimensional Equidistant Double Array

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Journal of Electronic & Information Systems 2019年第2期1卷 21-25页

作者： Tao Yu China electronics technology corporation China

On the basis of the linear positioning solution of one-dimensional equidistant double-base linear array,by proper approximate treatment of the strict solution,and by using the direction finding solution of single base path difference,the sinusoidal median relation of azimuth angle at three stations of the linear array is *** using the sinusoidal median relation,the arithmetic mean solution of azimuth angle at three stations is *** these results reveal the intrinsic correlation between the azimuth angles of one-dimensional linear array.

关键词： azimuth Double-base array Single base direction finding Arithmetic mean Median relationship Passive location

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azimuth发布Wi-Fi移动平台功耗测试解决方案

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电子产品世界 2006年第18期 95-95页

无线局域网工程测试设备供应商azimuth Systems系统公司最近在Globalpress组织的新闻发布会上发布最新Wi-Fi测试解决方案,可以帮助半导体制造商、无线手机厂商、PC厂商、其他消费类电子厂商以及无线服务供应商更好地测量无线移动平台的... 详细信息

无线局域网工程测试设备供应商azimuth Systems系统公司最近在Globalpress组织的新闻发布会上发布最新Wi-Fi测试解决方案,可以帮助半导体制造商、无线手机厂商、PC厂商、其他消费类电子厂商以及无线服务供应商更好地测量无线移动平台的功耗.

关键词：功耗测试套件测试解决方案 Wi-Fi azimuth 移动平台

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azimuthal elastic impedance-based Fourier coefficient variation with angle inversion for fracture weakness

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Petroleum Science 2020年第1期17卷 86-104页

作者： Lin Li Jia-Jia Zhang Xin-Peng Pan Guang-Zhi Zhang School of Geosciences China University of Petroleum(East China)Qingdao 266580ShandongChina School of Geoscience and Info-Physics Central South UniversityChangsha 410082HunanChina Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071ShandongChina

Quantitative inversion of fracture weakness plays an important role in fracture *** reservoirs with a set of vertical fractures as horizontal transversely isotropic media,the logarithmic normalized azimuthal elastic impedance(EI)is rewritten in terms of Fourier coefficients(FCs),the 90°ambiguity in the azimuth estimation of the symmetry axis is resolved by judging the sign of the second FC,and we choose the FCs with the highest sensitivity to fracture weakness and present a feasible inversion workflow for fracture weakness,which involves:(1)the inversion for azimuthal EI datasets from observed azimuthal angle gathers;(2)the prediction for the second FCs and azimuth of the symmetry axis from the estimated azimuthal EI datasets;and(3)the estimation of fracture weakness combining the extracted second FCs and azimuth of the symmetry axis iteratively,which is constrained utilizing the Cauchy sparse regularization and the low-frequency regularization in a Bayesian *** on synthetic and field data demonstrate that the 90°ambiguity in the azimuth estimation of the symmetry axis has been removed,and reliable fracture weakness can be obtained when the estimated azimuth of the symmetry axis deviates less than 30°,which can guide the prediction of fractured reservoirs.

关键词： Fracture weakness azimuth of the symmetry axis azimuthal Fourier coefficients HTI azimuthal elastic impedance

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Cumulant Correia tors and azimuthal Correlations in PP Collisions at 400 GeV/_(c)

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Chinese Physics Letters 1996年第4期13卷 253-256页

作者： WANG Shao-shun LI Zu-hao Department of Modern Physics University of Science and Technology of ChinaHefei 230027

The cumulan t correlators and azimuthal correlations of particles produced in protonproton(PP)collisions at 400 GeV/c are *** second-order cumulant correlators show that the two particle correlation length may be determined by comparing the experimental data with the Monte Carlo events sample which has same multiplicity distributions but no *** azimuthal correlation has also been observed.

关键词： correlation Collisions azimuth

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azimuthal AVO inversion of 3D P-wave and analysis of resistibility to noise

Azimuthal AVO inversion of 3D P-wave and analysis of resisti...

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CPS/SEG 2004 International Geophysical Conference

作者： Xiong Jinliang Petroleum University of China Beijing China Zhang Baoqing Li Guofa Computer Center Geophysical of Dagang China

＜正＞ Based on the high-precision reflection coefficient formula in the TIH （Traverse Isotropic with Horizontal axis） azimuth anisotropic medium, a corresponding inversion method is presented in this paper. The performance of the approach is tested on the theoretical models we designed. The results indicate that the method is correct and efficient. To verify the applicability of the P-wave azimuthal AVO inversion, a lot of numerical tests focused on the resistibility to noise have been done. And it is also hoped that these numerical tests can provide necessary references to Pwave AVO inversion processing of real 3D data.

关键词： P-wave azimuth AVO inversion TIH media resistibility to noise

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