Seismic methods have made huge leaps forward since their conception 80 years ago. EM-technology is poised for a similar development that promises, for example, far more detailed images of oil and gas reservoirs.
NGI is working to improve EM transmission and particularly reception. Programming used to analyse received signals and create images of reservoirs are also being continually improved.
Additionally, NGI has an ongoing project to install either EM transmitters or receivers, or perhaps both down into an oil well. In this way we close in on the reservoir and can take sharper snapshots. We believe in time that EM will be used to steer exploratory drilling for oil better. Sometimes oil companies drill a well and only marginally miss the reservoir. Here EM equipment can be lowered down the well to locate the reservoir's direction and extent, says NGI's civil engineer John Løvholt.
EM in the extraction phase
Until now EM has been applied mostly during oil exploration, but future EM technology will also be used during the extraction phase. A petroleum reservoir contains both oil and water and the distribution of these elements changes during extraction. Knowing this distribution is important to avoid for example forcing water into the well while oil may be still be in close proximity.
Although EM has long since proved its value, the technology has also had its setbacks in recent times. The maritime use of EM progressed so fast that many mistakes were made. Without adequate feasibility studies, huge amounts of data collected by contractors proved largely meaningless. The technology became somewhat oversold. Although not a contractor, NGI is rather a centre of competence, advising oil companies on how best to apply EM, says Andrea Aspmo Pfaffhuber.
EM used in multiple roles
The first EM equipment used by NGI in the late 1990's was loaned from university groups who still use EM for a wide range of geological surveys.
EM gives archeologists the opportunity to peek under the surface without excavating. NGI recognizes that EM in time will facilitate finding gas hydrates, mapping areas of quick clay and other geo-hazards, finding salt water seeping into freshwater reserves and so on.
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