Branch drilling gives extra NOK 1.3 billion from the Troll field

November 11, 2002, 00:00 CET

Drilling new areas of the Troll field has given very good results. Oil for NOK 1,300 million at today's oil price was rapidly added to the reserves after a fresh look at seismic data and application of advanced drilling technology.

"The branch wells that Hydro has drilled on Troll are a good example of the company's focus on increased oil recovery from existing fields," says Tor Madsen, who is in charge of Petroleum Technology in Troll Oil.

"Using seismic data, thorough geological assessments and new well technology together with existing seabed equipment, we have gone into areas that previously would have been too financially uncertain to drill."

The result in this round is two new branches on a closed well, which together increase oil reserves by 7.2 million barrels oil.

A "poor" well

The well in question, E-6, was originally completed in 1997. But production was poor, and the decision was taken to drill again in 2000, partly on the basis of 4D seismic data.

Last autumn, after further seismic studies, it was decided to add an additional branch to the well, a branch that would go into an undrilled area in the opposite direction of the branch that had already been agreed.

The decision to drill an extra horizontal branch in a previously unexplored area, was considerably easier as the new branch technology made exploration drilling far less costly than it would have been with conventional technology.

It took only 10 months from decision to drilling. The geological results in both the horizontal wells were better than expected, and it was decided that they should be extended so that the distance from toe to toe is now a remarkable 4.8 kilometers.

The well started producing oil for the Hydro operated Troll B platform on 6 November.