It was a long and difficult day on the witness stand for Mr. Noel Treasure, PTTEP’s senior representative on the West Atlas during the problematic 9 5/8″ casing cementing job. The transcript provides evidence of the stress that Mr. Treasure has been under since the blowout. While we are troubled by many of PTTEP’s actions at Montara, we nonetheless appreciate the difficult times that key participants in the incident are experiencing. Although no one was injured at Montara, the blowout will still have a substantial human cost. There are no winners.
Most of the disussion involved the key 9 5/8″ casing cementing issues including the serious miscalculation of cement volumes, the float failures and fluid influx, a remedy (reinjection of cement/fluids) that probably exacerbated the problem, the absence of a pressure test to check the floats, shoe, and casing after the cement had set, and internal confusion and miscommunication. Other testimony discussed the absence of a hydrostatic overbalance in the suspended well bore, the decisions leading to the use of corrosion caps as barriers in lieu of cement or mechanical plugs, and the failure to install the 13 3/8″ cap, partly because the well slot was being reserved as a “parking spot” for the BOP stack.
While the Montara blowout could and should have been prevented, the incident does draw further attention to the need for improvements in the consistency, reliability, and standardization of cementing operations. Cementing issues are associated with well control problems, sustained casing pressure in producing wells, and post-abandonment leakage. Best practices documents should not just address standard procedures, but also remedies, including actions that should be followed when irregularities, such as float valve failures, are identified.
Bud's Offshore Energy (BOE) 