Detailed Imaging of Seabed and Sub-seabed Geology from 3D Seismic Data Using Frequency Decomposition

The study focuses on detailed imaging of the seabed and the shallow sub-seabed sequences of a deep water area particularly affected by seabed features such as pockmarks, faults, carbonate hardgrounds and hydrate mounds. Three workflows that were applied to achieve this objective are discussed: noise cancellation, spectral enhancement and standard frequency decomposition with RGB blending. Noise cancellation was successful in attenuating much of the coherent and random noise present in the original data set. Vertical resolution, reflector continuity and event separation was improved by spectral enhancement. Frequency decomposition and RGB blending revealed a wide range of geological features on and under the seabed. With the help of these techniques one can distinguish the seabed features and identify and map different elements, such as faults, channels and pockmarks, as well as submarine landslides, mass transport complexes, outrunner blocks of varying sizes and corresponding glide tracks below the seabed. The results confirm that volumetric frequency decomposition and RGB blending lead to an improved and more reliable assessment of shallow geohazards by assisting interpreters to identify a wide range of geological features in unparalleled detail, in a reasonable amount of time.