In February 2002 Statoil Innovation established a subsidiary company ElectroMagnetic GeoServices (EMGS) to commercialize the group’s resistivity-based seabed ‘logging’ technique.

Hailed as a major breakthrough, the method involves:

• deploying a line of electromagnetic receivers on the seabed over a target reservoir

• a powerful electromagnetic source transmitting low frequency electromagnetic waves down through the underlying sediment column.

The principle is that energy is only refracted back to the surface when hydrocarbons or other highly resistive subsurface bodies are present.

Second generation refinements have extended the potential range of applications from water depths greater than 500 metres to those less than 500 metres.

Since the 2000 and 2001 trials off the coasts of West Africa and Norway, Statoil has run several surveys to further test and calibrate the system and assess its use for prospect evaluation.

These have shown that the method holds considerable promise, as long as the results are properly constrained by other geophysical data.

As of May 2004, EMGS has run 45 surveys involving 1 300 receiver deployments and 5 000 kilometers of source towing. Data have been acquired for more than 10 oil companies.

The method is now regarded as a proven risk reduction technique for locating offshore hydrocarbon reserves in such areas as the North Atlantic, Gulf of Mexico, Brazil, West Africa and South East Asia.

It can also be used to monitor hydrocarbon production.

Link to article in Statoil Magazine 01/2002 - page 45 to 47:

Making new waves (PDF-file)