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Dean, Don1, Kim Cline1, Bob Blackmur2, Allan Kean2, Marian Hanna2, Dave Smith2
(1) Veritas Exploration Services, Houston, TX
(2) El Paso Production, Houston, TX

ABSTRACT: Volume Visualization, Fast Track Interpretation, and Interactive Crossplot Analysis Lead to Discovery. A Case Study from Santos Basin, Brazil

El Paso entered the BS-1 block offshore Brazil in the Santos Basin in June 2002 in a farm-out from Kerr-McGee. The block expiration date was August 6, 2003. In July 2003 a gas and condensate discovery was made when a stratigraphic anomaly was penetrated. A fast track interpretation approach was utilized incorporating AVO attributes and volume visualization techniques to quickly identify leads. An off-structure Itajai age turbidite sand lobe with an AVO signature similar to the nearby Merluza field was chosen as the main prospect.
Workflow examples will be demonstrated that allowed a drilling decision to be made in a very short time frame. Initial quick look and identification of areas of interest were done by scanning an on-board processed post stack migration dataset. This was followed by a more rigorous examination of the pre-stack migrated volume with surfaces mapped based on amplitude and waveform criteria. AVO attribute volumes and existing well control were used with volume visualization techniques coupled with interactive crossplotting to identify pay and non-pay sands. Several leads at different intervals were identified and ranked based on their AVO signature, spatial continuity, and relationship to a depositional model. This is an iterative process done in real time with the asset team present to facilitate and speed up the decision making process.
The coordinated effort resulted in a discovery in a stratigraphic play type and opened the door for more prospectivity in an area that was previously deemed non-commercial.


AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.