Fast wave source localization with sparse measurements

2012 ◽  
Vol 132 (3) ◽  
pp. 1999-1999
Author(s):  
Anthony Sabelli ◽  
Wilkins Aquino
Keyword(s):  
Source Localization ◽  
Fast Wave ◽  
Wave Source ◽  
Sparse Measurements

scholarly journals Gravitational wave source localization for eccentric binary coalesce with a ground-based detector network

2017 ◽  
Vol 96 (8) ◽  
Author(s):  
Sizheng Ma ◽  
Zhoujian Cao ◽  
Chun-Yu Lin ◽  
Hsing-Po Pan ◽  
Hwei-Jang Yo
Keyword(s):  
Gravitational Wave ◽  
Source Localization ◽  
Wave Source

Seismic detection of a hydraulic fracture from shear‐wave VSP data at Lost Hills Field, California

Geophysics ◽  
1994 ◽  
Vol 59 (1) ◽  
pp. 11-26 ◽  
Author(s):  
Mark A. Meadows ◽  
Don F. Winterstein
Keyword(s):  
Shear Wave ◽  
Numerical Solutions ◽  
Scattered Wave ◽  
Hydraulic Fractures ◽  
Fast Wave ◽  
S Wave ◽  
Wave Source ◽  
Arrival Times ◽  
Fractured Medium ◽  
Fracture Closure

A shear‐wave (S‐wave) VSP experiment was performed at Lost Hills Field, California, in an attempt to detect hydraulic fractures induced in a nearby well. The hydrofrac well was located between an impulsive, S‐wave source on the surface and a receiver well containing a clamped, three‐component geophone. Both direct and scattered waves were detected immediately after shut‐in, when the hydraulic pumps were shut off and recording started. The scattered energy disappeared within about an hour, which is consistent with other measurements that indicate some degree of fracture closure and leak‐off within that period. Although S‐wave splitting was evident, no change was detected in the fast wave (polarized parallel to the fracture). However, the slow wave (polarized perpendicular to the fracture) did change over a period of about an hour, after which the prehydrofrac wavelet shape was recovered. The fact that only the wave polarized perpendicular to the fracture was affected is a dramatic confirmation of both theoretical predictions and laboratory observations of S‐wave behavior in a fractured medium. Subtracting the prehydrofrac wavelet from the wavelets recorded within the first hour after shut‐in revealed scattered wavelets that were diminished and phase‐rotated versions of the incident (prehydrofrac) wavelet. Arrival times of the direct and scattered waves were matched by ray tracing. We accounted for the scattered‐wave amplitudes by using numerical solutions of S‐wave diffractions off of ribbon‐shaped fractures. Amplitudes derived from full‐wavefield Born scattering, however, did not match recorded amplitudes. The phase of the scattered wavelets was matched very well by Born scattering when the incident wavelet was input, but only for fracture lengths no larger than half those predicted from fracture‐simulator models. These results show that a carefully controlled experiment, combined with accurate modeling, can provide important information about the geometry of induced fractures.

Characterization of porous rocks embedded with aligned fractures from shear wave responses

2020 ◽  
Vol 222 (3) ◽  
pp. 2172-2188
Author(s):  
Ding Wang ◽  
Bo Li
Keyword(s):  
Shear Wave ◽  
Dynamic Properties ◽  
Rock Fracture ◽  
Shear Waves ◽  
Symmetry Plane ◽  
Fast Wave ◽  
Porous Rocks ◽  
Anisotropic Rock ◽  
Vibration Direction ◽  
Wave Source

SUMMARY A single shear wave passing through an elastic anisotropic rock can split into two quasi-shear waves (noted by S1 and S2) with different polarization forms if the particle vibration direction of the wave source does not lie in the symmetry plane of the rock. This study focuses on the properties of shear waves penetrating a porous rock containing a set of aligned permeable fractures. The polarization characteristics of shear waves were selected to describe the dynamic properties of the rock as they are sensitive to the parameters of fractures and saturating fluids. From a physics viewpoint, in addition to the compressional wave, the shear wave (splitting) is governed by a wave-induced fluid flow (WIFF) process due to the specific shear stress decomposition happening on the fractures. The polarization formulas of S1 and S2 were derived based on the frequency-dependent Christoffel equation, which are related to the properties of fractures, fluids and wave frequency. The influence of the properties of fractures and fluids on the velocity and attenuation anisotropies of shear waves were analysed. The results showed that the particle oscillations of two shear waves are not completely mutually orthogonal, and are affected by the pressure equilibrium magnitude between the fractures and the corresponding interconnected pores. The S2 (slow) wave (i.e. particle polarized on the plane approximately perpendicular to the fractures) is more sensitive to the saturated fluids and the WIFF process than that of the S1 (fast) wave (i.e. wave polarized on the plane approximately parallel to the fractures). A frequency factor was proposed for quantifying the effects of WIFF on shear wave polarization and attenuation. Measurements on the unique polarization and the anisotropy of shear waves can provide a generalized indicator to predict the properties of fractures and the migration of infilling fluids in the rock fracture systems.

Stimulus discrimination and surface wave source localization in Crocodilians

Zoology ◽  
2020 ◽  
Vol 139 ◽  
pp. 125743 ◽  
Author(s):  
Nadja J. Grap ◽  
Tobias Machts ◽  
Sarah Essert ◽  
Horst Bleckmann
Keyword(s):  
Surface Wave ◽  
Source Localization ◽  
Stimulus Discrimination ◽  
Wave Source
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