Cost-efficient and Fit-for-purpose Monitoring using Surface Deployed Fiber Optics

Fiber-optic distributed acoustic sensing (DAS) technology is a technology that measures subsurface vibrations by probing the strain induced on a fiber-optic cable by an acoustic wavefield and has been demonstrated to provide a reliable alternative to traditional point receivers when deployed horizontally at surface (S-DAS). S-DAS, can record both P-wave (PP) and converted wave (PS) arrivals, is therefore well suited to monitoring CCS-related pressure and saturation changes when deployed in conjunction with a wider injection monitoring program. In recent years, we have demonstrated the significant potential of S-DAS imaging for both PP and PS wavefields. We report on our ability to image production-induced saturation changes and the potential to image production-based pressure changes, which provides valuable feedback in the early stages of the injection. We have demonstrated the key role S-DAS has to play as a low-cost seismic sensor, which can be interrogated over decades with no maintenance. Furthermore, through our novel acquisition geometry designs for S-DAS we also demonstrate its potential as a low impact, low acquisition footprint solution, lending itself to deployment in an adaptive manner, scaling the source effort to the phase of injection and monitoring objective; redefining the cost of seismic monitoring.