Hunting for Oil Under the Deep Brazilian Offshore Using mCSEM - The Petrobras Experience

Buonora, Marco Polo P.¹; Zerilli, Andrea ²; Labruzzo, Tiziano ²; Menezes, Paulo T.¹; Crepaldi, João Lucas ¹
(1)Exploration, Petrobras, Rio de Janeiro, Brazil. (2) BRGC, SCHLUMBERGER, RIO DE JANEIRO, Brazil.

Over the past six years, Petrobras has increasingly gained experience in marine Controlled Source Electromagnetic (mCSEM) through multi-client and proprietary surveys acquired over more than six distinct geological settings of the deep Brazilian offshore. These surveys were processed and interpreted as part of a technical cooperation between Petrobras and Schlumberger to assess the integration of deep reading Electromagnetics into the full cycle of oil field exploration and development.

The synergy between Petrobras and Schlumberger has led to an in-depth training of Petrobras professionals and significant advances on mCSEM technology understanding and development of new interpretation tools.

In this abstract, we present the potential of mCSEM and demonstrate the value of new interpretation using samples of the Petrobras database acquired over the Campos, Santos and few other Brazilian deep water basins, one of which referred as NE_1 Basin.

The Santos Basin survey was acquired to calibrate mCSEM over known reservoirs, quantify the anomalies associated with those reservoirs with the expectation that new prospective location(s) could be found.

High quality data from one hundred and eighty receivers spaced approx. 1 km apart were recorded. Data were processed using the actual survey parameters.

Interpretation was carried out using novel 2D and 3D anisotropic inversions with improved parameterization and knowledge integration.

Over a sector of the NE_1 Basin, an advanced inversion workflow detected a resistive structure associated with a risky seismic AVO in a complex setting which turned out to be an oil hit. The dataset is being investigated to optimize the workflow to assess the potential of mCSEM in identifying the reservoir properties through integration with seismic and well log data.

There are numerous aspects that must be considered to further develop mCSEM. One critical need will be the establishment of integrated interpretation solutions embedded in industry-standard applications. This will become apparent as additional mCSEM data are acquired in more complex settings and new high resolution approaches to mCSEM surveying for both appraisal and monitoring and integrated workflows using all available data to provide a consistent interpretation of the reservoir are needed.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.