45 research outputs found
Vertical Fracture Detection by Exploiting the Polarization Properties of GPR Signal
This is the publisher's version, also available electronically from "http://library.seg.org".Vertically oriented thin fractures are not always detected by conventional singleāpolarization reflection profiling groundāpenetrating radar (GPR) techniques. We study the polarization properties of EM wavefields and suggest multipolarization acquisition surveying to detect the location and azimuth of vertically oriented fractures. We employ analytical solutions, 3D finiteādifference timeādomain modeling, and field measurements of multipolarization GPR data to investigate EM wave transmission through fractured geologic formations. For surfaceābased multipolarization GPR measurements across vertical fractures, we observe a phase lead when the incident electricāfield component is oriented perpendicular to the plane of the fracture. This observation is consistent for nonmagnetic geologic environments and allows the determination of vertical fracture location and azimuth based on the presence of a phase difference and a phase lead relationship between varying polarization GPR data