Calibration Study. Experimental survey acquisition ASIL

Silixa makes the next generation intelligent Distributed Acoustic Sensor – capable of sensing the acoustic field at every meter along a length of fibre optic cable. A comparison was made between iDAS and reference sensors in both VSP and surface seismic orientations. Silixa provide optical cables and all optical paraphernalia, and also operated all iDAS-related equipment. At the end of the trial, Silixa provided the data to OGS for an analysis. The principal goal for this analysis is a comparison between the output of iDAS and that of conventional receivers. Silixa was supported by OGS for guidance concerning vibration points, vibrator sweep shape, sensor layout, and other issues related to standard seismic acquisition. From March 11th to March 29th 2013 GEOP group performed a survey with Silixa Ltd., a British company leader in Distributed Temperature Sensors (DTS) and Distributed Acoustic Sensors (DAS) development based on optical fibres sensing technology1 . The goal of this experimental survey is the calibration of Silixa iDAS technology with reference seismic sensors, i.e. geophones, for both land lines and VSP. For this purpose the geophones locations must match a subset – taken on a regular basis - of the sensing positions along the fibres, by the surface-line side, since the sensing fibres need to be buried 1 meter deep underground. The trial was performed at Piana di Toppo OGS instrumented test site. The test site is provided by facility for logistics, where Silixa instrumentation was hosted together with the OGS equipment.