EVALUATION OF ELASTIC IMPEDANCE ATTRIBUTES IN OFFSHORE HIGH ISLAND, GULF OF MEXICO

Date

2012-05

Journal Title

Journal ISSN

Volume Title

Publisher

Abstract

In certain areas, seismic AVO alone is not sufficient for interpretative purposes. This necessitates the use of other seismic attributes. The High Island Field, a Tertiary basin in the Gulf of Mexico, has values of acoustic impedance for shale and gas-saturated sands that are approximately equal. Conventional 3-D seismic data has had limited success in detecting hydrocarbons in this area. Also, synthetic seismograms are difficult if not impossible to tie to seismic data. To solve these problems, I employed the elastic impedance and extended elastic impedance attributes. Results from this research show significant amplitude increase with offset for a gas-saturated reservoir as compared to brine-saturated reservoir. The elastic impedance volume derived from the far-angle stack delineates the reservoir better than the elastic impedance volume from the near-angle stack. With respect to reservoir characterization, the five seismic attributes (Vp/Vs, bulk modulus, shear modulus, Lamé, and shear impedance) generated from the extended elastic impedance inversion helped to determine the lithology and predict the pore-fluid type of the reservoir. In conclusion, the use of additional seismic attributes (elastic impedance and extended elastic impedance) helps to achieve a better reservoir characterization especially in a Class 2 environment.

Description

Keywords

Elastic impedance

Citation