By an OGJ correspondent
RIO DE JANEIRO, Aug. 12 -- Petroleo Brasileiro SA has confirmed a major deepwater oil discovery at the edge of the Campos basin off Brazil's Espirito Santo state.
Appraisal drilling and production testing of a January 2001 discovery have yielded an estimate of reserves totaling 600 million boe. The crude is 17° gravity with no sulfur.
Plans call for two more appraisal wells to further delineate the find plus a long-term production test of an extended-reach appraisal well drilled last month.
Jose Coutinho Barbosa, Petrobras exploration and production director, said the find was the company's biggest since 1996, when the company discovered Roncador giant oil field in the deepwater Campos basin. The find is near Roncador and extends the Campos productive trend to the north.
Drilling details
The Brazilian state firm drilled the 1-ESS-100 discovery well to TD of 3,154 m on Block BC-60 in in 1,246 m of water 80 km off Espirito Santo state in January 2001. Petrobras owns the block 100%.
It is the first major hydrocarbon discovery off the state; all of the major finds in the Campos basin to date have occurred off Rio de Janeiro state, immediately to the south.
The discovery well cut a 46 m thick pay zone with reservoir characteristics similar to those seen elsewhere in the prolific Campos basin, which accounts for 80% of Brazil's oil production.
In May of this year, Petrobras spudded a confirmation well, 6-ESS-109D, 3 km away from the discovery well. This well cut a pay zone of 120 m in the same formation as the discovery well but also encountered at 25 m oil-bearing reservoir—in an older formation—not found in the discovery well.
Last month, Petrobras drilled an extended-reach appraisal well, 3-ESS-100HPA, with a horizontal displacement of 1,000 m. Initial tests of this well yielded flow rates of 3,000 b/d.
Testing, drilling plans
Petrobras has scheduled a 6 month, long-term test of the extended-reach well, using the Seillean floating production storage and offloading vessel, to get a better handle on the reservoir's producibility.
In that long-term test, slated to begin this month, Petrobras will use for the first time in Brazil an electrical submersible pump rated to more than 20,000 b/d.
In addition, the Brazilian oil giant has scheduled two delineation wells to gauge the extent of the new field during the coming 6 months. These two wells are expected to cost $10-12 million apiece.
Following the additional testing and appraisal drilling results, Petrobras plans to submit a report on the field's commercial viability and a development plan to the National Petroleum Agency (ANP). Should development prove viable, Barbosa estimated that the field could produce as much as 120,000 b/d of oil within 3 years. He said that the long-term test could yield flow rates as high as 20,000 b/d, comparable to other Campos basin fields.
Barbosa also speculated that the reserves estimate for the new discovery could escalate, as only the main part of the reservoir has been evaluated so far.
The discovery is near the confluence of the Campos and Espirito Santo basins. The latter has yet to see a major oil discovery, although a handful of minor fields produce oil onshore nd from shallow waters nearshore.
ANP awarded the oil and gas concession for this block to Petrobras in 1998, in the first auction of acreage in Brazil since Congress in 1997 passed a law ending the Petrobras monopoly. The so-called "zero auction" was limited to Petrobras; four subsequent annual actions have included private companies.