Nondestructive measurements and evaluation has great significance in various domains of science, engineering and technology. The ob- jective of this research is to investigate the anisotropic behavior in a sandstone sample from non-invasive tests using Laser Doppler Vi- brometer coupled with Piezoelectric Transducer and to validate these results using a laboratory scale controlled hydraulic fracturing ar- rangement. High-resolution 3-component single-point seismograms were generated for the core sample using a combination of 1 MHz Piezoelectric Transducer as a source of elastic waves that travel within the reservoir rock sample and Laser Doppler Vibrometer as the re- ceiver. Hilbert transforms of the 3-component data were calculated to obtain the complex signal. Shear wave splitting phenomenon due to anisotropy in rock was examined and the resultant SH and SV wave polarizations were measured. Elastic tensor for the core sample was subsequently determined from the velocity picks within the Hilbert energy envelope followed by the estimation of Thomsen’s parameters. The hodogram analysis was performed to assess the process of shear wave splitting in the rock sample that detects the anisotropy of the medium and this, in turn, specifies the characteristics of weakness planes. Laboratory scale controlled hydraulic fracturing was performed to verify whether the fractures propagate along the anisotropic planes of weakness. Real-time fracture detection was carried out during this process and its propagation features were studied. The fractured core sample was imaged under the slice Computed Tomography scan machine to perceive the mode and propagation of fractures in the rock specimen.
|Journal||Annals of Geophysics|
|Publisher||Instituto Nazionale di Geofisica e Vulcanologia, INGV|