Petroleo Brasileiro SA, Brazil's state oil company, is pressing the hunt for billion-barrel fields in the deepwater Campos basin.
Latest evidence of the company's high success rate in the deepwater basin is a significant oil discovery near Corvina and Marimba producing oil fields.
Petrobras has made Offshore Campos exploration and development a priority in its program aimed at achieving oil self-sufficiency for Brazil in the 1990s. It also recently stepped up activity in the remote Amazonas basin of the nation's jungle interior (OGJ, Feb. 12, p. 19).
CAMPOS STRIKE
Petrobras' latest success in the deepwater Campos basin is 1-RJS-412, completed in January. It flowed on production test 3,000 b/d of 27 gravity oil from Eocene Carapebos sandstone at 2,940-47 M.
The well cut 23 m of net pay at 2,939-62 m and bottomed at 3,132 m.
Petrobras has approved two appraisal wells-3-RJS-437 and 3-RJS-438-within 2.5-3 miles of the discovery.
The structure, identified by 3D seismic, covers an area of about 20 sq km-about the areal extent of Corvina-and lies in water depths of 400-800 m. Site is about 90 km from Cape Sao Tome, Rio de Janeiro state.
Based on the size of the indicated reservoir, seismic data, and comparisons with analogous reservoirs in the vicinity, Petrobras estimates the new field could hold potential reserves of 100 million bbl of oil.
Reservoir characteristics are similar to those in Corvina, which produces 15,000 b/d of oil, Petrobras said. Nearby Marimba produces 20,000 b/d of oil.
OTHER EXPLORATION
Petrobras has spudded a wildcat near the 1-RJS-412 strike to test another structure thought to be on trend with the discovery.
Petrobras 1-RJS-373A is drilling in about 570 m of water about 9 km northwest of the discovery.
It also plans a wildcat, 4RJS-419D, in 277 m of water just east of Malhado field. East of the discovery, Petrobras plans another wildcat, 1 RJS-425, in 925 m of water.
Both will be drilled during the first half of 1990.
Based on extensive seismic interpretation-if the appraisals meet expectations and the subsequent wildcats yield commercial oil from reservoirs comparable to the latest discovery-Petrobras estimates the combined resource potential covered by the current drilling campaign in the central Campos area at about 1 billion bbl of oil in place.
CAMPOS SIGNIFICANCE
Despite the high costs of working in deep and ultradeep waters of the Campos basin, Petrobras has high hopes for more success, given the basin's high success rate.
Petrobras has a 40% wildcat success rate in the deepwater Campos basin. Including appraisal wells, that success rate jumps to 60%.
The Campos basin provided about 60% of Brazil's total oil production of 638,000 b/d in January.
That compares with 360,000 b/d out of a total 580,000 b/d a year ago (OGJ, Feb. 13, 1989, p. 26).
Petrobras last year targeted Brazilian production at almost 1.5 million b/d by 1997, with the Campos basin to provide about 1.08 million b/d of that. Budget cuts by the financially strapped company forced it to abandon its production goal of 700,000 b/d of oil by December 1989.
Copyright 1990 Oil & Gas Journal. All Rights Reserved.
