Unmanned Mapping of Ultra-Shallow Water Environment in The Framework of CCS Project in Liverpool Bay

Between March and June 2022, Eni S.p.A and Eni UK Limited undertook the acquisition of a 500 km² bathy-morphological survey in the CS004 license in the framework of the HyNet Project, where Eni UK will develop and operate the onshore to offshore transportation and storage of CO2 in three depleted gas fields in the Liverpool Bay.

The main aim of the survey was the collection of seabed and sub-seabed data with sufficient penetration and resolution to set a baseline for monitoring activities and to de-risk subsequent seismic operations and engineering design in the area.

The articulated context of Liverpool Bay is mainly affected by ultra-shallow bathymetry, strong tidal excursions (up to 8 m) with their related currents, presence of surface infrastructure (O&G platforms and wind farms among the others) and heavy marine traffic.

This required a careful analysis in terms of acquisition feasibility, survey strategy and safety of operations. In particular, the paper focuses on the successful use of a fleet of Unmanned Surface Vehicles (USV) as a valuable approach for bathy-morphological data collection, highlighting the good-quality results against the local constraints and the repeatability of this acquisition method in other similar challenging environments.