Geo Oceans was engaged to conduct a full subsea pipeline inspection survey using Autonomous Underwater Vehicles (AUVs). The field features a fixed, unmanned wellhead platform connected to an onshore gas processing plant via a long-distance subsea pipeline. Gas is processed onshore, while condensate is exported offshore via a single-point mooring. The field is remotely operated and maintained, with regular subsea inspections and periodic off-takes supporting a long production life.
AUV Pipeline Inspection Survey
Equipment
Geo Oceans operates the IVER 3 AUV, a compact, modular autonomous submersible supplied by L3Harris. This lightweight unit (≈45 kg) is deployable from small vessels or shore and is equipped with high-resolution side-scan sonar and interferometric bathymetry. It enables efficient, multi-pass pipeline surveys with accurate mapping of pipeline position, free spans, debris, and seabed changes. The AUV reduces inspection duration from weeks to days, cuts operational risk and cost by minimising diver and ROV usage, and improves data quality with dense, contactless imaging. Its open architecture allows sensor customisation, making it a flexible and effective solution for high-resolution subsea assessments.
Scope
A comprehensive geophysical survey was completed using two IVER 3 AUVs operated in rotation for continuous coverage. The scope included inspection of approximately 115 km of pipeline using a three-pass acoustic methodology to detect free spans, debris, and seabed anomalies. A focused 500 m x 500 m debris survey was also conducted around the platform to map infrastructure and seabed features. Operations were completed in water depths ranging from 2 m to 55 m under high current conditions, covering a total of 505 km over 17 incident-free days. A compact three-person crew managed mobilisation, QA/QC, and data acquisition, with rapid half-day mobilisation and demobilisation. Deliverables included processed side-scan sonar and bathymetric data, mosaics, contact reports, bathymetric charts, and structured event listings. Near real-time cloud-based data transfer enabled swift report generation.
Outcome
All project deliverables were completed on time, on budget, and without safety incidents. The dual AUV deployment enabled seamless operations, achieving 505 km of coverage in 17 days. Key objectives included a three-pass inspection of 115 km of pipeline, a high-resolution debris survey around the platform, and data capture in dynamic marine conditions. Deliverables—such as side-scan mosaics, bathymetric surfaces, contact listings, and detailed reports—met or exceeded expectations. The AUVs performed reliably, and the real-time data uplink allowed for efficient processing and reporting, contributing to the successful completion of the project.