New Positioning Technique Helps Cut Costs in Deepwater GOM

During a recent 10-day project in the Gulf of Mexico for a major E&P company, the use of inertial navigation technology reportedly reduced vessel time by three to five days over the course of the deployment and positioning of seismic data acquisition modules. Prior to this sea-trial, precise underwater positioning was achieved by dropping and calibrating an array of acoustic beacons on the seabed - a timeconsuming process that requires deployment, calibration and later recovery of the beacons.

"A significant increase in productivity and reduced safety risk was achieved using the Kongsberg Maritime Hydroacoustic Aided Inertial Navigation (HAIN) system, while maintaining the accurate placement and positioning of the modules," said George Buhler.

Positioning & Navigation Consultant for C&C Technologies, one of three service providers on the project, together with Fairfield Industries and Sonsub. "The equipment was mounted on a remote operated vehicle (ROV) and was ready to work as soon as it arrived onsite. Furthermore, the positioning accuracies we achieved were comparable to those of traditional technologies throughout a range of water depths." By using an inertial system as the primary method for ROV navigation and positioning, the team determined that inertial technology can be used to replace an array of acoustic beacons as the primary source of navigation and positioning for a variety of seabed operations that require precise navigation and positioning. With fewer points of failure and a lower safety risk due to a significant reduction in back deck operations; this successful sea-trial was a first step in introducing this new technology to deepwater oil and gas ROV operations.

The seismic data acquisition modules were Fairfield Industries' Deep Z Pods, a self-contained, 4C recording sensor for Azimuth Long Offset, full-wave seismic data acquisition in deepwater. The project took place in water depths ranging from 4000 to 7000 feet using a Sonsub Innovator ROV deployed from the support vessel HOS Innovator.

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