New positioning technique reduces costs and improves productivity in deepwater GOM
  by: OilOnline
  Monday, August 09, 2004

Houston, TX ... During a recent ten-day project in the Gulf of Mexico for a major exploration and production company, C & C Technologies' use of inertial navigation technology reduced vessel time by three to five days over the course of the deployment and positioning of seismic data acquisition modules. Prior to this successful sea-trial, precise underwater positioning was achieved by dropping and calibrating an array of acoustic beacons on the seabed – a time-consuming 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. The equipment was mounted on a remote operated vehicle (ROV) and was ready to work as soon as it arrived onsite.

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.