Brazilian Pre-Salt Frontiers to Expand

Companies such as Petrobras, Repsol, Anadarko and Shell have made important pre-salt discoveries away from the Picanha Azul area where the Tupi field is located and where all the blocks drilled presented commercial hydrocarbon accumulations.

Repsol is making history in Brazil with block ES-T-737, where they are drilling to a goal depth of 7,500m (24,606ft). Repsol is hedging on finding oil under the salt layer in an area beyond officially recognized pre-salt boundaries. The area where block ES-T-737 is located, lies between the northern boundary of the Campos Basin and the southern boundary of the Espirito Santo Basin, around 87km northeast of the Jubarte Field at the Whale Park, on the southern part of the Espirito Santo Basin.

The Jubarte field which had its first pre-salt oil extracted September 2008, was the main test bench for technologies to be used at the Tupi field on year later, including reservoir reaction to drilling, salt layer drilling techniques, FPSO production systems and drilling safety issues.

In the Repsol ES-T-737 block area the salt layer is believed to be over 3,000 meters thick, whereas at the Tupi field and the majority of other known pre-salt areas the salt layers have an average area of 2,000 meters. This alone is requiring special drilling equipment, but there is also the fact that to get to this salt layer, the Stella Drill Max Drillship, which is executing this deepwater drilling project for Repsol, had to cover a 2,160 meter water depth and nearly another 2,000 meters of marine stones and sediments to breach the post salt layer.

New seismic technologies are allowing more thorough form of reservoir detection, thus permitting new field beyond the officially established pre-salt polygon, which comprises a region 800 km long. Other locations in the Northeast of Brazil such as off the states of Bahia, Sergipe and Amapa and possibly even all the way up to Pernambuco are also expected to contain respectable pre-salt reserves according to some important Brazilian geologists, however this information is not acknowledged by Petrobras. There are also rumors that there is true potential for pre-salt reserves further offshore than the Tupi field. Recent pre-salt discoveries in Gabon in West Africa also give credibility to these theories.

These new discoveries are immensely important as they come before the next round of bidding, which will most probably only occur in 2011 after the national elections, due to ongoing political negotiations. This delay may even be interesting as it will give the Government and ANP more time to establish a new pre-salt map and decide upon which areas will be considered strategic. This same delay is exasperating international investors , but in the end of the day, there is no doubt they will play by whatever the tune is, as all want a piece of the pre-salt pie. Only time will tell if it’s a positive or negative situation for Brazil.

Claudio Paschoa

Photo courtesy of Repsol