Seismic acceleration signal analysis and application
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Seismic acceleration signal analysis and application* Zhang Huai-Bang1, 2, Li Lu-Ming 1, Zhang Guang-De2, Zhang Bo-Han3, and Sun Miao-Miao2 Abstract: Although various types of geophones are applied in seismic exploration, there are only three common types of signals produced by geophones: displacement, velocity, and acceleration signals. Currently, our understanding of the signal characteristics, such as the generation mechanism, the geophysical properties, and the significance of the corresponding rock physics, remains unclear, which makes it difficult to both scientifically evaluate and take full advantage of the different types of geophones. In this paper, the mechanism by which seismic waves are generated is studied based on the spring–damped vibration theory. The physical characteristics of the three above-mentioned signal types and the relationships among the physical properties of the signals and medium are analyzed, as well as the signalto-noise ratio (SNR), resolution, and spectrum characteristics. Based on laboratory tests, field experiments, and applications, we obtained the following conclusions. The acceleration signal reflects the elastic characteristics of the medium and the change rules, and the signal strength is positively correlated with physical property changes. The acceleration signal has favorable attributes, such as small distortion, high fidelity, strong high-frequency amplitudes, and a wide frequency band. Therefore, the acceleration signal is more suitable for high-precision seismic exploration of complex media. In addition, the P-wave acceleration signal more accurately reflects the elastic Young modulus, shear modulus, and density changes than the velocity signal. However, the sensitivity decreases with increasing shear modulus and density. For the S-wave, the acceleration signal is more sensitive to the shear modulus and density than the velocity signal. Keywords: acceleration signal, velocity signal, signal fidelity, resolution, signal-to-noise ratio.
Introduction With rapid developments in seismic exploration technology, the density of seismic acquisition channels has gradually increased from hundreds of thousands to
millions or even tens of millions per square kilometer. Geophone reception methods have evolved from geophone arrays to single-geophone reception. Wired seismographs are distributed as a wireless nodal acquisition system (Lansley et al., 2008), and multiset multi-stack vibroseis excitation has changed to
Manuscript received by the Editor June 03,2019; revised manuscript received March 8,2020. *The research is supported by the National Major Science and Technology Project of “the 13th Five-year Plan”(No. 2017ZX05005004003). 1. School of Geophysics, Chengdu University of Technology, Chengdu 610059, China. 2. The Shengli Branch of the Sinopec Petroleum Engineering Geophysics Co., Ltd., Dongying 257086, China. 3. School of Ocean and Earth Sciences, Tongji University, Shanghai 200092, China. ♦ Corresponding author: Zhang Huai-Bang (Email: [email protected]). ©2020 The Editorial De
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