NGI and Statoil announced EM boom

Norwegian oil companies might have continued to use seismic surveys alone had it not been for a key person in Statoil in 1998 with funds available from a research budget as Christmas drew near.

Concept sketch for seabed logging, Dr. Kong, 1988

A small delegation from Statoil was in the US and witnessed early attempts with EM in and between closely located drilling wells. Harald Westerdahl and Fan-Nian Kong from NGI were given the challenge: Can electromagnetic see-bed logging be used to determine whether a reservoir in substrata contains oil or water?

The answer was expected to be "no", but the NGI researchers began computations and model calculation on their pc's.

Most feasibility studies do not give favourable results and remain on the shelf, but not this time. This story tells something about the importance of non-appropriated research funds says John H. Løvholt from NGI's department of Instrumentation and Geophysics. He had been administratively involved in NGUI's EM activities since its beginning in 1998.

The oil company Exxon Mobil experimented with EM back in the sixties, and amongst others, the University of Southampton and the American ocean research institute Scripps have used EM for differing purposes since then. However, the continuing boom for use of marine EM for surveying hydrocarbons was clearly triggered by testing at NGI.

The principle for seabed logging using Controlled Source EM-technology: A horizontal electric dipole (HED) is towed from a cable with recording sensors on the seabed. The towed source broadcasts a controlled EM energy signal. Areas of high electrical resistivity, e.g. sediment layers containing hydrocarbons, deflect the induced electric currents. Electrical and magnetic fields are recorded by seafloor receivers and with subsequent sophisticated data processing and analysis, the signals can be used to indicate the presence of water or petroleum in underlying reservoirs. (From Kong et al. 2008).

Expansion stagnated
Only ten years after initial studies at NGI, a fleet of about ten ships dedicated to marine EM surveying operated in all major offshore search areas worldwide. The offshore industry was interested in and enthused by this new addition to the tool box for finding oil and gas. Nevertheless, the global finance crisis of 2008 had an extreme negative impact on this relatively new member of the family and the marine EM industry is at present in a period of consolidation and re-evaluation.

With this uncertainty in the market, NGI's independent and solid research is of great value for energy companies and future participants in the market for EM exploration.