--> An Integration of Genetic Inversion and Seismic Frequency Attributes to Delineate Reservoir Targets in Offshore Northern Orange Basin, South Africa
[First Hit]

AAPG Annual Convention and Exhibition

Datapages, Inc.Print this page

An Integration of Genetic Inversion and Previous HitSeismicNext Hit Frequency Previous HitAttributesNext Hit to Delineate Reservoir Targets in Offshore Northern Orange Basin, South Africa

Chris A. Samakinde1

1 Department of Earth Sciences, University of the Western Cape, University of the Western Cape, Capetown, Western Cape, South Africa

April 5, 2017 Wednesday 8:30 A.M. AAPG Annual Convention and Exhibition, Houston, Texas

Abstract

A combination of genetic inversion (Previous HitSeismicNext Hit Impedance and Porosity) and Previous HitseismicNext Hit Previous HitattributesNext Hit (Instantaneous Frequency and Iso-Frequency) are used to characterise Albian and Cenomanian clastic reservoir targets in offshore, northern Orange Basin. The reservoirs are mapped from the well Af-1 position throughout the Previous HitseismicNext Hit volume after initial Previous HitseismicNext Hit-well tie and consequently, Time-Depth relationship established. Frequency filtering was performed as a form of post stack Previous HitseismicNext Hit processing technique to remove passive noise and enhance geological features. Previous HitSeismicNext Hit acoustic impedance inversion calibrated with porosity inversion reveals the presence of fluvial channels and associated point bars deposit within meandering channels within the Cenomanian and Albian sequence. The identified channels expectedly show high porosity along its geometry compared to its surrounding lithology. Iso –Frequency (Frequency decomposition) using the Cosine Correlative Transform (CCT) was applied to identify the sweet spots. Iso- frequency of 45 Hz, 12 Hz and 8Hz windows were captured to isolate hydrocarbon charged reservoirs within the Albian and Cenomanian sequence. The CCT method shows that 8Hz window resolved stratigraphic features present within the Previous HitseismicNext Hit volume but unable to resolve the presence of hydrocarbon charged reservoirs. However, the application of Instantaneous Frequency (IF) attribute reveals the presence of hydrocarbon charged Cenomanian reservoirs in close proximity to a fault judging by the attenuation of frequency observed. This was achieved by using Thirty –three Previous HitseismicNext Hit traces as an input in the Hilbert transform window, subsequently, trace envelope and instantaneous phase were transformed into instantaneous frequency. This study demonstrates the effectiveness of integrating different Previous HitseismicNext Hit Previous HitattributesTop as a non-invasive approach in characterising clastic reservoirs.

AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017