New technology and inter-disciplinary cooperation mean that Statoil is now drilling production wells on Statfjord in the North Sea at a fraction of the cost of conventional drilling.
It costs around NOK 15 million to drill a Statfjord well. With conventional drilling the cost is often three times as much.
Through-tubing drilling is efficient because it is not necessary to retrieve and re-run the production tubing in the old well. This means less time spent and lower material costs.
Statfjord has drilled three such wells. The latest, A-23B, took 19 days from start-up to the time the well was in production. Initially, the well produced 5,000 barrels of oil per day, and costs were recovered in 14 days, reports Øystein Arvid Håland, manager for Statfjord resource development.
“For a mature field such as Statfjord it is important to penetrate the reservoir in many places in order to retrieve as much of the residual oil as possible. That’s why it’s crucial to reduce the costs per well,” he adds.
On average, 16 sidetrack wells are drilled on the field annually. A third of the production is a result of last year’s drilling and well initiative. The objective is to have 50 identified drilling targets available at all times, says Mr Håland.
The main Statfjord field currently produces 190,000 barrels of oil per day. Ninety per cent of the producible oil has been recovered. The objective is to continue profitable production until 2020. Gas production will be decisive for profitable operations and gas will also make it possible to recover more oil.
“We are now carrying out a project for the later phase, which will result in an operational strategy as the field approaches the end of its life. We will submit a plan based on this project to the authorities,” affirms Mr Håland.