Chevron Corporation yesterday reported that the operations have been in progress in partnership with Brazilian government agencies to contain, reduce and eliminate the remaining oil sheen in the vicinity of its Frade field. The sheen, estimated at approximately 18 barrels or less in volume, is located about 120 kilometers offshore Brazil and continues moving away from the coast.
“Chevron takes full responsibility for this incident,” said Chevron Brazil country manager, George Buck. “We are committed to deploying resources until the sheen can no longer be detected.”
Up to 18 vessels have been in rotating operation to support well plugging operations and sheen cleanup. The vessels are using oil response methods approved by the Brazilian government, such as deployment of containment booms and surface skimming. At no time has sand or chemical dispersants been used in the process.
Chevron is analyzing data to estimate the total volume of oil released from the incident. This analysis is expected to be complete within days. Brazil’s National Petroleum Agency (ANP) had estimated the total volume of oil released at approximately 5,000 to 8,000 barrels.
“Our emergency response teams are trained and prepared to address a potential spill incident,” said Buck. “The moment the seeps were first identified, we immediately activated our emergency response plan and began dispatching necessary resources to safely manage the situation. We moved quickly to begin plugging and cementing procedures to seal the source. Our combined efforts greatly diminished the size of the sheen and stopped the source of the seep flow within only four days of first detection. We believe no new oil is seeping from the reservoir. Seep lines continue to drain in the form of droplets.”
Regarding Chevron’s preliminary assessment of the incident, Buck said, “We were drilling toward a targeted reservoir and encountered an unexpected pressure spike or ‘kick’. We believe the kick caused fluid to move into the wellbore and increased pressure opened a segment of the wellbore. Fluid then escaped to reach thin fissures and migrate to the ocean floor. The well was safely shut in, following standard operating procedures. All equipment performed as expected. A complete investigation is underway to understand the cause of the incident. Findings will be shared with Brazilian government agencies and Chevron’s global operations to prevent this from happening again.”
Chevron said that it informed ANP of its well plan before drilling started. The plan included targeted depths and the targeted reservoir.
The company said it would continue to cooperate fully with all authorities as it has throughout the incident.
Development drilling operations in the field remain suspended. Production from the Frade field has been maintained with volumes of approximately 79,000 barrels of oil equivalent per day.
Offshore Energy Today Staff , November 21, 2011; Image: Chevron