From gas to oilIfølge Slottet mottar Hans Christen Rønnevik utmerkelsen for sin innsats innen petroleumsgeologi. Foto: Halfdan Carstens

From gas to oil

Judged to be gas prone, it was later proved to be very oily with multiple, prolific structrues. Hans Chr. Rønnevik tells "the story behind" in May.

Alvheim is a major Lower Tertiary oil field producing from the clustered Kneler, Kameleon, Boa and Snailhead (East Kameleon) discoveries. The Boa discovery straddles the Norway-UK boundary and constitutes a separate cross border production sub-unit.

The first well was drilled in 1998. Well 24/6-2 found gross 52 meter gas and 17 meter oil in Heimdal Mbr sandstone of generally good quality. Located in the vicinity of the Norsk Hydro operated Heimdal gas field, the Kameleon discovery was early evaluated as a gas satellite development.
Following the transfer of operatorship from Norsk Hydro to Marathon it was agreed to conduct a 4 well  exploration drilling campaign in 2003 to decide on development of  gas satellites to Heimdal or a clustered oil field solution.
The appraisal campaign in 2003 resulted in a 48 meter under-saturated oil column found in the Kneler structure. An oil column of 28 meter below a gas cap was found in Boa. Only a small gas and oil column was found in the Gekko appraisal well. The Snailhead part of Kameleon was known to offset the main trend and was later proven to have two stacked saturated reservoirs.
Later exploration and appraisal of the Volund, Kobra and Bøyla discovery has turned the Alvheim oil development from a gas satellite candidate to a successful oil hub close to the Norwegian-UK border.
At the NCS Exploration – Recent Discoveries May 23-24, Hans Chr. Rønnevik will give a talk entitled «The Alvheim Area Exploration phase – from gas satellite to oil hub«. Arild Jørstad is co-author.