Subsea Drilling: How Do They Work on the Ocean Floor?

I've gotten lots of questions the last week about my posts on the BP blowout of their Mississippi Canyon Block 252 well and how they do all the work on the ocean floor in 5,000 feet of water. I've also gotten some requests for diagrams of the operations that I've been describing the last couple of days, talking about the blowout preventer, cementing, casing hanging, and plug setting. I fully realize that some of my descriptions of operations can be confusing to those not familiar with how oil wells are drilled, and I've been looking for some videos that might be helpful. I've found a great series of animations on youTube that are of Total's development of the Dalia Field, off of West Africa, in about 4,000 feet of water. The equipment on the BP well may be a little different than in the video, but the technology and techniques are the same. Here's a good video on how the blowout preventer is landed and the controls hooked up by ROV (turn your volume down; the music is pretty grating):

Here's another one that illustrates hanging off and cementing of casing. It also shows how the packoff (that likely failed in the BP well) is set and tested:

Hopefully, these animations are helpful. If nothing else, they clearly illustrate the level of sophistication of the technology used a mile under the water.

There's a lot more about the BP well blowout on The Daily Hurricane Energy Page