User:Macquigg/Sandbox/Blowout preventer

Figure 1. Schematic of the Deepwater Horizon blowout preventer. Order from the top is 2 annular preventers, 2 shear rams, and 2 pipe rams. The bottom unit is a test ram.

Figure 2. Annular blowout preventer

Figure 3. Cross-section of a typical shear ram

Figure 4. Looking down the bore of a pipe ram

This sandbox article is a collection of things we might want to add to Blowout preventer. We need better drawings, especially the annular preventer. The level of detail needed is what we have in Figure 3, enough to understand the mechanism, but not a complete machine drawing.

Summary

There are three types of blowout preventers: annular preventers, shear rams, and pipe rams. Annular preventers and pipe rams make a tight seal around the outside of a drill pipe. Shear rams (aka blind rams) cut through the drill pipe and seal everything, including whatever might be coming up inside the drill pipe.

Both annular preventers and pipe rams close around the pipe, but annular preventers have more of a vertical motion, so they loosen slightly if the drill pipe is being pushed downward, as might be necessary in a snubbing or well kill operation. Shear rams are used as a last resort, because they destroy the drill pipe and limit options for further work.

External links

Deepwater Horizon blowout preventer - dimensioned drawing of externals from DOE Open Government website.

Photo of subsea BOP -still no detail of internals, but this looks very similar to the one on the DOE website.

Inside the Blowout Preventer - illustrations for NY Times article 6/21/2010.