A production well with a total measured length of about 10,000 metres being planned to tap the Gulltopp discovery will rank as the longest so far drilled by Statoil.
Previously known as Dolly, Gulltopp will be produced from the group’s Gullfaks A platform in the North Sea.
The well will be drilled as a sidetrack from an existing producer and is costed at almost NOK 300 million, reports drilling superintendent Sven Arve Askedal.
The Gulltopp production well will be about 10,000 metres long. (Illustration: Anne Lise Tveit)
This represents a quarter of the investment which would be needed to develop the discovery with a subsea template and dedicated multiphase flowline for the wellstream.
The well will be deviated to an angle of roughly 83 degrees from the vertical at the point where it penetrates the reservoir, and then to 90 degrees through the formation.
“Drilling with such high deviations isn’t unusual,” says Mr Askedal. “The challenge lies in the total length planned for this well.”
He notes that Statoil already has good experience of drilling extended-reach wells from Gullfaks.
But the Gulltopp project can add to existing expertise in this area and thereby help to make a number of other small Norwegian oil and gas prospects commercial.
A series of such potential sources reachable by platform-drilled wells have been identified in the Gullfaks area alone.
Drilling is due to begin in October to tap Gulltopp’s estimated recoverable reserves of just over 25 million barrels of oil and 500 million cubic metres of gas.