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26/09/2006 The Earth’s crust split apart between Norway and Greenland more than 50 million years ago. Huge quantities of lava spread in thick layers across several hundred square kilometres of seabed, and left today’s geologists with a big headache.
Text: Jan Stenløkk
Photos: Jan Stenløkk
This article was first published in Norwegian Continental Shelf no. 2-2006
These eruptive rocks lie hundreds of metres beneath the modern seabed. Little is known about what might be concealed under them, because volcanic basalt is an extremely dense material.
Even with today’s technology, “seeing” though such layers is very difficult. But many oil geologists believe that big assets could be concealed in petroleum-bearing strata below the ancient outpourings in the Norwegian Sea.
“These basalt layers represent a major challenge,” conceeds NPD principal geologist Christian Magnus. “But we can’t afford not to survey the areas concerned.”
So the NPD has teamed up with the Force industry forum in a project which aims to identify possible hidden treasures in this highly interesting part of the NCS.
The goal is to learn so much about the rocks under the thick layers of basalt that these areas could become attactive for petroleum operations.
Work kicked off last year with the creation of a project group drawn from eight oil companies and led by the NPD, which held a two-day meeting at the agency in late March.
Representatives from the whole petroleum industry and academic circles in Norway, the UK, the Faroes and Denmarkattended this session, which sought to establish a common understanding of the way volcanic rocks developed on the NCS.
Phase two involves continued work on geophysical and geological issues. A new working party has been established, with the NPD proposed as its leader. Participating companies undertake to make capital, expertise and human resources available.
The project group is now discussing what must be done to increase knowledge of the “subbasalt” area, as geologists term the rocks beneath the volcanic layers.
“This information can be acquired in several ways,” explains Mr Magnus. “These include reinterpreting seismic data already gathered from the relevant areas, performing new surveys or carrying out scientific drilling.”
The Force team could cooperate with academics on drilling through the basalt, perhaps in cooperation with the integrated ocean drilling programme (IODP).
“There’s also interest in establishing the thickness of this basalt,” Mr Magnus says. “The volcanic activity generated by the separation of Norway and Greenland continued over millions of years, so we’re not only talking about a single layer of basalt but multiple deposits of varying thickenesses.”
Thick layers of eruptive rocks are also found on the Faroese continental shelf, he notes.
“The Faroese government has carried out two licensing rounds in sea areas with this type of geology. Interest has been great, and applicants have included Norway’s Statoil.
“Two-three wells are soon to be drilled in the awarded areas, and these are attracting great
Force: The forum for reservoir characterisation, reservoir engineering and exploration (Force) brings together oil companies working with exploration and improved recovery on the NCS. Its secretariat is provided by the NPD, while the Research Council of Norway participates as an observer. The forum works to qualify a number of methods and techniques for improved recovery, and to stimulate industry cooperation on boosting exploration efficiency and quality as well as enhancing the reliability of resource estimates on the NCS. (www.force.org) geological and financial attention.”