• Oil and gas

Surveying the subsea scene

Deep tow survey solution for LUKOIL in Romania 

When Russian oil and gas company, LUKOIL wanted to check that an area off the coast of Romania in the Black Sea was clear for development it contacted James Fisher Marine Services (JFMS) for an ROV.

However, the JFMS team quickly realised a tailored deep-towed subsea survey would be a more effective option, and took on the contract.

Over 60 ancient shipwrecks had been discovered in the area in recent years and Romanian environmental law required LUKOIL to check the area ear-marked for development was clear before conducting an exploratory drilling campaign.

LUKOIL, and the local diving authorities, had little experience of a survey of this scale having previously used a platform-based solution only suitable for smaller areas. However, the JFMS team contracted a support vessel with a winch attached to a ‘towfish’ (a weighted fibreglass shell fitted with side-scan sonar equipment) which was able to sweep the 8km x 6 km area.

Jennie Kevis-Stirling, survey specialist for JFMS explains:

‘The ‘towfish’ was kept at around 10m above the seabed so its sensors could scan the seabed as depths undulated between 800-1300m and identify any targets lying there, or buried up to 10m beneath the surface.’

This survey method allowed the JFMS team to reduce the length of the project from an expected 30 days to just a week, and post-analysis of the data revealed no targets of potential archaeological interest, meaning the Romanian authorities could issue an Archaeological Discharge Certificate and LUKOIL can now proceed with drilling and construction operations in the field later this year.

‘This was the first time JFMS had provided a deep-towed subsea survey but the success and acquired expertise means we can now expand the survey options the team is now able to provide,’ 

Added Jennie.

JFMS deploying the 'towfish'
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