Tank cleaning system is safer, greener and more cost-effective

Statoil, which says it has been looking for a way to make tank cleaning on offshore supply vessels safer and more effective, has awarded a contract to M-I SWACO to develop a new solution. The oil major has awarded M-I SWACO a contract valued at around NKr 500 million (US$56 million) to do so. The four-year contract includes options for a further four years.

The automated system means personnel need not enter the tanks on a vessel in order to clean them. Wash water and detergent are also recycled, so it is only the actual waste washed out of the tank that has to be processed further. Statoil says it has not used this type of technology on supply vessels before, but M-I SWACO has used such a solution on its own vessels. This is the first time the Schlumberger-owned company has commercialised the technology.

“This solution increases the safety of our personnel as there is no need to enter tanks, and we reduce both time and cost,” said Jone Stangeland, vice president of logistics and emergency preparedness at Statoil.

Typically, manual tank cleaning is carried out by emptying the tanks of any residual volume of cargo, before personnel enter them, erect scaffolding and clean them. Manual tank cleaning usually generates a high volume of waste. “By cleaning the water in the same operation, the volume of waste is reduced significantly,” said Mr Stangeland. Another advantage of the truck-mounted system is that vessels will spend much less unproductive time docked in connection with tank cleaning. The new system will fit onto a truck.

Statoil said it is constantly searching for new technology that can reduce its environmental footprint. Another example of this approach is that all of the supply vessel newbuilds that have entered long-term contracts with the company in the past two years have been modified to use shore power. They will also be equipped with a generator that can be used instead of the main engine, when the vessel is docked.

“We have also specified strict requirements for NOx emissions, and all new vessels are equipped with trip computers so the crew can monitor fuel consumption, and adjust the speed and log fuel consumption more efficiently,” said Mr Stangeland.

M-I SWACO is well known as a supplier of drilling fluid systems, fluid systems and specialised tools designed to optimisze work offshore, such as wellbore productivity. It also specialises in production technology solutions to maximisze production rates, and environmental solutions to manage waste volumes generated in both drilling and production operations. Nowadays, it is part of Schlumberger.