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New plug cuts costs

June 16, 2004, 11:05 CEST

The process of completing new oil and gas wells and preparing them for production has been simplified by a new plug system developed with backing from Statoil.

Recently used on the group’s Snorre field in the North Sea, this device is the brainchild of Bergen-based Total Catcher Offshore (TCO).

”We’ve had great faith in this project, and are very pleased that the plugs have proved to function as intended,” says Kristian Sirevaag, manager for well intervention in Statoil.

”This invention represents a long step forward in efforts to simplify the processes related to drilling and production.”

During completion, wells are tested with plugs before production begins. One challenge has been to create devices which can withstand high pressure and temperature.

At the same time, they must be both installable and retrievable in the simplest possible way when production is due to begin.

The TCO plug meets these criteria, with the pressure and temperature challenge solved by using glass sheets which can withstand up to 135°C and 100 tonnes of pressure.

Fitting the plug with a pyrotechnical unit also makes it easy to remove. When subject to a certain number of pressure pulses, the device collapses so that hydrocarbons can begin to flow.

Unlike much traditional technology, this solution also avoids any narrowing of the production liner. That boosts production and simplifies maintenance, which in turn improves profitability.

Savings from using the glass-based plugs on Snorre came to an estimated NOK 2 million, or 1.5 rig-days.

Statoil has previously tested the device on its Norne field in the Norwegian Sea.

According to Sveinung Robertsen, the group’s discipline leader for downhole mechanical isolation, the system will be adopted on several of the fields operated by Statoil.

He notes that many of the small technology companies in Norway’s oil and gas industry are characterised by great innovative capabilities.

”We also want to facilitate technological advances in such firms, so that we and they can jointly achieve good results to ensure the best possible utilisation of oil and gas reserves.”