Enhancing subbasalt reflections using parabolic τ-p transformation

Abstract

Potential hydrocarbon-bearing sediment structures in the Faroe-Shetland Basin are often overlain by basaltic sequences of stacked flows up to several kilometers thick. With conventional seismic acquisition and processing methods, it is difficult to image the internal (intrabasalt) and underlying (subbasalt) structures. Scattering from the highly reflective top of the basalt and short-period multiples from intrabasalt boundaries may completely mask reflections from the base of the basalt and below. High attenuation of seismic energy in the basaltic sequence due to its complex internal structure generally causes a weak subbasalt signal. Long-period multiples, such as those generated between the sea bottom and the top-basalt boundary, may obscure subbasalt reflections and energy reflected from the basement.