First Pre-salt Spill Highlights Deepwater Challenges

The accident that occurred on Tuesday, January 31 on the Dynamic Producer FPSO owned by Brazilian company Petroserv at the Carioca Nordeste field in the Santos Basin is a good example of the hard challenges found when drilling and producing in deepwater wells.

During an extended well test a production column broke causing the spilling of approximately 160 barrels of oil (equivalent to 25 thousand liters). Although this can be considered a small spill, as compared to the 2,400 barrels spilled by Chevron at the Frade field in the Campos Basin in November 2011, it still a serious problem that needs to be addressed, the media didn´t pick this up but the fact is that this same problem occurred on the Dynamic Producer during well tests in the Guara pre-salt field also in the Santos basin a year ago to the month.  During the well test in Guara there was no spill as there was no oil in the production column but the column also broke and the well test had to be postponed.

The Carioca Nordeste field is located at the BMS-9 Block located 293km (182 miles) from the coast of the state of São Paulo. The well is 2,140 meters deep. Most deepwater production specialists contacted believe the fault was caused by strong shifting currents, but some also speculate that it could have been caused by some fault in the ships dynamic positioning system and also on a possible flaw in the construction of the production column. With the production column going down over 2km to the wellhead, there are massive forces at play and maintaining the structural integrity of the free-hanging column is no easy task. At present there has been no official announcement on what caused the production column to break, but there is no doubt that this reoccurrence of the same problem is a major concern to Petrobras. With many deepwater wells still to be tested and also Petrobras´s palns to build deepwatrer FPSO´s and deepwater drillships in Brazilian shipyards problems such as these will need to be solved forthwith in order to avoid more problems and potential accidents in the future. Petrobras has its own specialized group working on the problem and the national operator has also contracted a foreign company to address the issue and find solutions to this nagging problem. Petrobras has a 45% share of Carioca Nordeste with BG 30% and Repsol 25%.

Claudio Paschoa