UTEC Survey’s Australian business unit completed a major infield inspection covering 550km of pipelines and 20 infield structures, off northwestern Australia using its Gavia autonomous underwater vehicles (AUV).
One of the AUVs in a sling.
Photos from UTEC.
The work, for Apache Energy, on its North West Shelf pipelines, started in mid-June using two Gavia AUV systems, equipped with a full suite of survey sensors, deployed from the Yardie Creek vessel. The inspection was completed in under four weeks.
UTEC operated the two AUVs on a “back-to-back” basis – when one system returned from a mission, the next one was ready to go immediately. In some cases the operational up-time in a given day was improved by as much as 40% through the “back-to-back” use of the AUVs.
The AUVs are low logistic modular Teledyne-Gavia Offshore Surveyor AUVs, which travel at up to 4knots in 4-1000m water depths. The AUVs are positioned with INS aided via LBL/USBL or emulated USBL. For the operation, the AUVs were fitted with INS module c\w Kearfott T24 and ROVINS-90, aided by RDI 1200 kHz DVL, a sonar module, nose cone stills camera and obstacle avoidance sonar, control module including acoustic modem for USBL aiding and MST 900/1800 kHz side scan sonar, two battery modules and a propulsion module.
UTEC Australia General Manager Simon Hird said: “AUVs are a developing technology. Our AUV Center of Excellence in Houston is constantly striving to deliver new and improved capabilities, some of which were applied on the Apache project. The quality of data gathered and presented from an AUV survey is astonishing in terms of visible detail.”
As well as the Apache project, offshore Australia UTEC has involvement in the Saipem Ichthys pipelay project; a long term contract to provide survey and positioning services on Woodside’s Nor Australis operations support vessel; recent completion of a major subsea inspection program in Bass Strait, and a geotechnical investigation project relating to the Ichthys development.
|UTEC’s Gavia AUV.|