Together with his colleague Jan Petter Morten, Mittet published the paper The marine controlled-source electromagnetic method in shallow water in the March/April edition of Geophysics, a Society of Exploration Geophysicists publication.

Amplitude from thin resistor compensates for airwave

It has been well known that the amplitude of the airwave increases with reduced water depth. This effect was previously assumed to dwarf the response from a hydrocarbon-charged reservoir in shallow water. The paper by Mittet and Morten shows that also the response from a hydrocarbon-charged reservoir increases as the water depth is reduced. This amplification effect is sufficiently strong to compensate for the growth in airwave amplitude and makes marine CSEM in shallow water feasible and effective.

Finding the needle in the haystack

Mittet drew an analogy between a haystack and the response from a thin resistive layer (reservoir):

“Identifying the response from a reservoir in a strong-background field can be compared to looking for a needle in a haystack. If the volume of that haystack (airwave) becomes 10 times larger you have your work cut out for you. However, if the needle, meaning the response you get from the reservoir, also increases in size with a factor of 10, the chance of success stays the same.”