Case History 1 Field Appraisal With Three-Dimensional Seismic Surveys Offshore Trinidad
Robert M. Galbraith, Alistair R. Brown, 2011. "Case History 1 Field Appraisal With Three-Dimensional Seismic Surveys Offshore Trinidad", Interpretation of Three-Dimensional Seismic Data, Alistair R. Brown
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A consortium operated by Texaco Trinidad Inc. commenced exploration in the South East Coast Consortium block offshore Trinidad in 1973. After four years of intensive exploration, a gas/condensate discovery was announced in early 1977 on the Pelican prospect. Later that year, in anticipation of the possible future need to site drilling/ production platforms, a three-dimensional (3-D) seismic survey was recorded over the prospect. This survey resulted in improvements in seismic record quality, multiple attenuation, and fault resolution. A coordinated geologic-geophysical interpretation based on the 3-D seismic survey, a re-evaluation of log correlations, and the use of seismic logs differed significantly from earlier interpretations. Because of this, it is anticipated that the development of the field will need to be initiated in a different fault block from that previously envisioned.
A second 3-D survey contiguous to the Pelican survey was recorded in 1978 over the Ibis prospect. Results show significant data enhancement in the deeper part of the section and improved fault resolution relative to previous two-dimensional (2-D) control. The 3-D interpretation has revealed a much more complex fault pattern than originally mapped. Separate fault blocks will have to be individually evaluated, thus greatly increasing exploration risk.