Towards using harmonic "contamination" as signal for thin reflectors

Christopher B. Harrison, Gary F. Margrave, Michael P. Lamoureux, Arthur Siewert, Andrew Barrett, J. Helen Isaac

Vibroseis is currently the favoured source used for seismic land acquisition where conditions permit. A pilot signal generates a sweep of designed length and frequency range which drives the vibrator to impart a signal into the earth. Due to non-linearity in the vibrator hydraulics and mechanical systems, as well as near surface non-linearities, higher order harmonics of the pilot signal are generated, “contaminating” both sweep and the seismic record. Traditionally these higher order harmonics have been targets for attenuation during acquisition and processing. In 2011 CREWES and POTSI developed algorithms to decompose these harmonics within a “contaminated” vibrator sweep. In this paper we explore the use of these decomposed harmonics for bandwidth expansion for better imaging of thin beds.