Patenting seismic sniffing

September 28, 1999, 10:00 CEST

A patent is being sought by Statoil for a new seismic survey tool which can provide important supplementary data in offshore exploration.

This "seismic sniffing" solution has been developed in cooperation with de Groot-Bril Earth Sciences (dGB) in the Netherlands, which will market and sell the product.

It represents the first technique which allows the flow of hydrocarbons below ground to be mapped, explains staff geophysicist Roar Heggland in the exploration and production technology (LUT) unit.

Applying this tool has demonstrated a relationship between known oil and gas fields and the flow of hydrocarbons to the surface of the bedrock.

Such flows can be observed to some extent in seismic data with existing methods, but attempts at mapping them without the help of seismic sniffing are very imprecise and inadequate.

This also demands a good deal of manual labour, which in turn takes a long time.

In earlier periods, when oil companies concentrated largely on fields close to the surface, finds were made by "sniffing" the flow of hydrocarbons above such reservoirs.

Flows from deeper fields can now be identified using the new Statoil tool and combined with standard interpretation of seismic images.

The new technique is automatically able to identify and map different objects in these images, explains staff geophysicist Paul Meldahl.

Apart from hydrocarbon flows, these objects could be fractures, formations and hydrocarbon traps in the sub-surface.

Seismic sniffing was adopted internally in Statoil last November in connection with Norway's "North Sea" offshore licensing round, and has also been used for the forthcoming 16th round.

The tool is due to be presented internationally by Statoil and dGB at the annual conference of the Society of Exploration Geophysicists in Houston, Texas, this November.