The work was done by UTEC Survey Australia using two of its Gavia autonomous underwater vehicles.

Offshore work started in mid-June from the survey vessel Yardie Creek and was completed in less than four weeks.

For the first time UTEC operated two autonomous underwater vehicles back-to-back; when one returned from a mission the next was ready to go immediately.

In some cases, the operational up-time in a given day was improved by as much as 40%, thanks to this efficient use of the vehicles.

UTEC Australia general manager Simon Hird said autonomous underwater vehicles were a developing technology where UTEC had a leading edge.

"Our AUV Centre of Excellence in Houston is constantly striving to deliver new and improved capabilities, some of which were applied on the Apache project," he said.

"The quality of data gathered and presented from an AUV survey is astonishing in terms of visible detail."

UTEC has customers lined up for its autonomous underwater vehicle services too, with involvement in the Saipem Ichthys pipe lay project, the recent completion of a major subsea inspection program in Bass Strait and a geotechnical investigation project relating to the Ichthys development.