Seismic geomorphology of giant foresets formation, Taranaki basin, New Zealand

Abstract

The Taranaki Basin covers an estimated area of 330,000 km² along the western side of the North Island, New Zealand. There is currently the only producing petroliferous basin in New Zealand. The high thickness and rapid accumulation of The Giant Foresets formation will have a significant impact on the petroleum systems of Taranaki Basin. 3D seismic data are the main data that used in this study to understand geomorphology in subsurface such as characteristics of channels, slump scars, and sand bars distribution. In this study area, small –scale channels with thin-bed cause a difficult in seismic detection and interpretation, thus seismic attributes used in this study for extracting more information from the seismic data will help to illustrate the geomorphological features of the area. The ability of seismic attributes can be divided into two groups. The first group including RMS amplitude, sweetness, instantaneous frequency and spectral decomposition attribute that is good for detecting the difference of lithology such as sand distribution and sand bodies geometry imaging. The second type is variance attribute which good to detect discontinuity seismic data or geological structure. The dominant of geomorphology features are channels which have 2 sizes including major channels (Width: approximately 150-500 meter) and Minor channels (width: approximately 50-150 meter). Most of their characteristic of channels is straight to low sinuous channels associated with sandbars and slumps scar. So, the deposition environment should be slope aprons environment. Although the Giant Foresets Formation has minor reservoir potentials, but knowledge of using seismic attributes might be beneficial for applying with the deeper petroleum explorations either.