An investigation of key seismic attribute analysis of the Whitehill Formation in the Karoo Basin

Abstract

The object of this study is to determine the thickness of the Whitehill formation based on historic seismic data provided by the Council for Geoscience (CGS). The thickness of the Whitehill was determined through the development of a velocity model and extraction of velocities at each picked location for the horizon in question. Amplitudes data was also extracted to determine if the data could be used to establish possible anomalies that could represent hydrocarbon prospects in the Whitehill formation. Ninety nine seismic lines were selected for the purpose of this study in the south western part of the Karoo Basin. It has been noted that due to the lack of velocity logs and sonic logs that a velocity model was created to determine depth conversion. This has been used to create depth and time variation maps, amplitude variation maps and isopach maps across the Whitehill formation. Essentially the data proved acceptable in establishing the topographical shape and depth of the Whitehill but lacked in estimating the thickness, due to the base of the Whitehill being difficult to discern. It was concluded that the results produced acceptable results for estimating the depth of the Whitehill and in some areas the thickness of the Whitehill but due to the poor quality of the data it could not produce accurate results from the HVA and the amplitude variation maps.