DAS Deployed at Seabed for CO2 Storage Monitoring

The work presented in this paper is a first step to assess the capabilities of fiber optic cables deployed at seabed to acquire and process 4D seismic data to monitor future CO2 storages. A data set acquired with a Permanent Reservoir Monitoring (PRM) system installed at seabed has been analyzed. Four-component (4C) optical sensors are interconnected by optic fiber cable along a 2D line and active seismic shots located above this optical cable have been simultaneously recorded by the 4C sensors and by DAS along the optical cable connecting these 4C sensors. This data set is ideal to compare the sensitivity of DAS versus the one of conventional sensors. The first step was to understand what is physically recorded by these optical cables. Then, a PP processing sequence has been applied to the PZ summation (combination of hydrophone and vertical component of accelerometer), the radial component of accelerometer and the DAS. The results obtained are very encouraging and are clearly placing fiber optic cables horizontally deployed at seabed as part of the next generation of CO2 storage monitoring toolbox.