A field trial of cross-well seismic with DAS and a high-frequency source

Distributed acoustic sensing (DAS) technology is routinely applied at different stages of resource and mines' exploration, development and monitoring. Naturally, deployment of an optical fibre in a borehole is favourable for obtaining high-quality data due to its cost-effectiveness and high-density coverage and provides rapid acquisition of downhole seismic data. Many tasks that require the use of high frequency-source to achieve necessary resolution primarily focused on investigations for mineral exploration and near-surface monitoring. Cross-hole is one of the methods employed for locating small-size mineral bodies and monitoring near-surface changes. Here, we present the results of a cross-hole acquisition using DAS and a high-frequency electric sparker source. The field trial was conducted at the CO2CRC's Otway International Test Centre, Victoria. A sensing fibre optic cable was cemented in a shallow well and a sparker source was deployed in a separate borehole. Data were collected using the DAS Treble+ interrogator (Terra15 Technologies Pty Ltd). High-resolution seismic data, obtained in this project using the high-frequency source demonstrates the applicability of DAS technology for near-surface studies like CO2 leakage monitoring and mineral exploration.