Utilising well tractor technology has cut Statoil’s downhole maintenance costs by several hundred million kroner.
After participating in the development and introduction of this service, the group ranks as a world leader in the application of a cost-effective solution which is much in demand.
”We saved NOK 500 million on such operations in 2003,” reports Stephen Stragiotti, discipline leader for mechanical cable and tractor operations in well interventions in Statoil's Technology entity.
”In addition, our earnings increased by NOK 300 million because production wells were brought on stream faster and the recovery factor could be improved.
”We receive many enquiries from other oil companies around the world about the use of these tractors.”
This six-metre-long device is an electrically-driven wheeled vehicle which pushes equipment as much as eight kilometres along the horizontal sections of oil wells.
The cable which supplies a tractor with power is used to extract it from the well once an operation has been completed.
Applications include plugging, perforating and logging in production wells, but are being steadily extended to help maintain output from commercially-marginal producers.
Statoil did seven tractor-based operations on fields it operates in 1996, but that figure had risen to 71 in 2002 and was no less than 127 last year.
”These devices ensure particularly good resource utilisation because they improve the recovery factor on a field,” says Mr Stragiotti.
”They can also demonstrate good results for health, safety and the environment, because equipment is simpler and crews smaller than with alternative methods.”
Since they were first tested by Statoil in 1996, well tractors have covered an accumulated distance of 1 700 kilometres through horizontal wells operated by the group.