I was talking today with one of our other supervisors who knows a lot of guys that still work offshore. I know what I'm about to say is probably gonna go over most people's heads, but I'm gonna try and explain it to the best of my ability.
They were cementing the well. This is when they cement in between the casing (the metal pipe that makes up the well bore) and the formation outside of the casing. They began to take a "kick", which is a high pressure jump caused by various downhole issues, most of the time it is pressure pockets or gas pockets. The cement supervisor on duty at the time told the Company Man, which is the BP representative on site, that the kick was coming. They were displacing, or pushing the cement into the formation, with regular sea water. In well control we have what is called "hydrostatic pressure", or in other words the pressure caused by a column of fluid. Just like when you go deeper in a pool and it makes your ears pop, that is called "hydrostatic pressure". Now when you take a kick, you must overcome it with heavier fluids, which raises your hydrostatic pressure. The heavier the fluid the more pressure it creates downhole. So, if you have a kick pressure of 8000 psi, the hydrostatic of the fluid you use must equal at least 8000 psi to keep the kick in check. Back to the story, the supervisor knew they needed a heavier fluid than seawater to handle the kick. He told the Co Man this and the co man told him that he had done the calculations and seawater was heavy enough. Well, needless to say it wasn't. That is the cause of the blowout itself, and the BOP's (blowout preventers) obviously didn't do there job either. They were getting pieces of the packing gasket back at surface and the Co Man told them to keep working as they were almost done.
Sorry if that got a little technical, hopefully I made it fairly understandable.
