Print this pageAAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Bump to Prospect: An Empirical Approach to the Recognition and Characterization of Isolated Carbonate Buildups on Seismic Data
(1) Dept Earth Sciences, Royal Holloway University of London, London, United Kingdom.
(2) Onshore Exploration (UIX/E/A), Shell Petroleum Development Company of Nigeria Ltd, Lagos, Nigeria.
Isolated carbonate platforms are well-known and attractive targets for hydrocarbon exploration in both frontier and mature basins. They are attractive because they can form potentially large-volume stratigraphic-trap features with generally reduced charge, reservoir, seal and trap risk relative to other types of carbonate plays. Unfortunately, undrilled features imaged on 2D and 3D seismic that could be isolated carbonate platforms are often difficult to identify unequivocally because other geological features such as volcanoes, tilted fault blocks and erosional remnants have somewhat similar geometries and modes of occurrence. Consequently explorers require a method of systematically identifying potential leads and reliably de-risking play elements and prospects suspected to be isolated carbonate buildup features.
Using a database of more than 200 seismic images of proven isolated carbonate buildups and other similar features, a set of reliable empirical criteria has been developed to identify isolated carbonate platforms, especially in frontier regions and or areas with sparse seismic data. The dataset includes proven examples from the Upper Paleozoic to Neogene in age, occurring in several different tectonic settings. Using these data it is possible to investigate some of the variability in platform architecture likely to have arisen due to variations in tectonic settings and in carbonate producing factories through time.
The identification criteria can be divided into four main categories: (i) regional and stratigraphic constraints; (ii) general morphology and basic geometries (Figure 1. yellow boxes); (iii) geophysical characteristics; and (iv) smaller-scale geometries and associated internal features (Figure 1, green boxes). These criteria represent a progression in detail of interpretation, from an initial regional overview, through basic large-scale seismo-stratigraphic interpretation, to simple analysis of some geophysical properties, and finally to consideration of more detailed aspects of the seismo-stratigraphy. Working through these criteria and compiling results on a simple score-sheet provides a practical framework for isolated buildup identification, initial de-risking, and thoughtful interpretation.