Well tractor technology has cut Statoil’s downhole maintenance costs by several hundred million norwegian 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.
Cost comparisons conducted by the Well Intervention Department have shown that the company saves approximately NOK 500 million annually on such operations.
In addition, the group's earnings are increased by NOK 300 million annually due to;
- the cost effectiveness of tractor operations making it feasiable to recover even small production volumes of oil, hence improving the recovery factor for marginal reserves.
- tractor operations require less lead time to mobilise so that new production and injection wells are brought on stream faster.
- The well intervention tractor is typically an electro-hydraulically, five to six metre long device.
The vehicle is used to push equipment as much as nine kilometres along the horizontal sections of oil or gas wells.
The cable which supplies a tractor with power from surface 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. Since 2003 the group has conducted approximately 130 tractor operations annually.
The use of tractor devices ensure particularly good resource utilisation because they improve the recovery factor on a field.
In addition, they can also demonstrate good results for health, safety and the environment, because equipment is lighter, simpler and crews smaller than what is required with alternative methods such as coiled tubing or snubbing.
Since they were first tested by Statoil in 1996, well intervention tractors have covered an accumulated distance of more than 3000 kilometres through horizontal wells operated by the group from 1996 through 2005.