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1. (WO2018130272) A METHOD FOR FAST DETERMINATION OF THE LOCATION OF AN ACOUSTIC EMISSION EVENT IN A VTI/TTI MEDIUM

Pub. No.:    WO/2018/130272    International Application No.:    PCT/EP2017/050446
Publication Date: Fri Jul 20 01:59:59 CEST 2018 International Filing Date: Thu Jan 12 00:59:59 CET 2017
IPC: G01V 1/28
Applicants: READ AS
Inventors: HALDORSEN, Jakob B.U.
Title: A METHOD FOR FAST DETERMINATION OF THE LOCATION OF AN ACOUSTIC EMISSION EVENT IN A VTI/TTI MEDIUM
Abstract:
A method for fast determination of the location of a hypocenter of an acoustic emission event for a Vertical or Tilted Transverse Isotropic formation, each having a symmetry axis, by means of at least three receivers comprising spreading the receivers out perpendicular to a symmetry axis for wave velocities; defining independent source/receiver sagittal planes as planes parallel to said symmetry axis that include the location of the receiver and either the particle movement polarization vector of compressional waves (P waves) or vertical shear waves (Sv waves) generated by the acoustic emission event, or the planes perpendicular to the particle movement polarization vector of a horizontal shear wave (Sh wave) generated by the acoustic emission event; defining an event epicenter as a single point where all the sagittal planes intersect with a plane perpendicular to the symmetry axis, and where said point represents a projection of the event hypocenter, and estimating the true hypocenter for an acoustic emission event from the epicenter by a 1D migration along a single line through the event epicenter along the symmetry axis.