A BP plan review prepared in mid-April recommended against the full string of casing because it would create “an open annulus to the wellhead” and make the seal assembly at the wellhead the “only barrier” to gas flow if the cement job failed. Despite this and other warnings, BP chose the more risky casing option, apparently because the liner option would have cost $7 to $10 million more and taken longer.
While the circumstances and details differ significantly, Montara (Timor Sea blowout) flashed across my mind repeatedly while reading this informative letter from Chairmen Waxman and Stupak to BP. Common themes:
- Well integrity roulette: high risk well design
- Suspect production casing cement job
- Only one questionable barrier above the cement
- Multiple poor decisions on barriers
- Schedule concerns, time and efficiency pressure
- Failure to run Cement Bond Log and conduct confirming tests
- Mud weight and conditioning issues
Bud's Offshore Energy (BOE) 
Bud!
I am glad that we are now starting to see some facts coming to surface. On the other hand I am shocked at the apparent lack of understanding of what barriers and qualifications are required on the outside of the casing. We saw some of the same attitude at the Montara hearing.
It is almost as if a lot of people think that if we have mud in the hole and a BOP we are OK – it is not that simple. Once this is respected it should also make people think about whether their production casing is a secondary barrier at all!
Tore Fjågesund
Good points Tore. This is why everyone who works on offshore facilities should study the major accidents – historical and recent. I wonder if any of BP’s drilling personnel knew what happened at Montara?