Question about the oil Rigs?

[STVmod]

I know that their are people on here that are a lot more knowledgeable about this than i am. i don't know or have any experience in underwater operations. So their must be a simple answer to the question i have.



i have seen pictures and detailed diagrams of the complete unit and safety valve system that appears to me was assembled on dry land and then put into place on the sea floor. if that is correct, WHY do they not have a safety manual operated valve that can be screwed on or off to be a simple emergency backup. i understand the safety valves that were in place that were supposed instantly cut the well of in a case of something like this happening, and i know that a manual valve would have leaked the whole time that a submersible took to get down their. But a simple gate valve seems to me needs to be mandatory piece of safety equipment on any underwater well cap.

i am interested in the answers.

Fletcher:cheers:

[transomstand]

The BOP is a stack of 6 valves that can instantly shut the well. Some are a shear ram valve, that can cut right through the drill pipe. What has not been reported, is how badly damaged the BOP is. The shear valve was only able to partly close, because the drill pipe was being driven upward by the explosion. There are manual overrides, the ROV's were trying to use them, but the shear valve will not close fully.
This may actually be good luck, the BOP is so badly compromised, it may not be able to hold the pressure if fully closed. It could actually fall apart, or even be blown off the ocean floor. If it did close, the drill casing below it is also badly damaged, and could also blow out, forcing oil out the ocean floor.
The BOP is being used as well as it can right now, guiding oil to the surface. It can't be trusted to hold the pressure of a firm seal.

[CDave]

Once a well is completed and in operation there is a SSSV, SubSea Safety Valve and also a SSV=surface safety valve. The SSSV and SSV are held open by pressure. If the signal line looses pressure, for any reason, it automatically shuts. This valve wasn't installed yet because the well wasn't operational.
Transomstand, answered ya question. I'm posting this in case some might think that the wells in the GoM aren't protected once the drilling rig leaves.

[Euroski]

I watched on discovery channel last week and they said the seals were blown off on the safety BOP valves. I also watched an old show dated 1994 on the same channel which was about drilling in the North Atantic because the Gulf wells didn't produce that much oil(lol)... the BP well looks like a BIG winner.

[STVmod]

i figured their was a good explination for it... and you also aswered my followup question which was why cant they put a pressurable soft seal to seal off the pipe comming up, it makes a lot more sense to me now.



This may actually be good luck, the BOP is so badly compromised, it may not be able to hold the pressure if fully closed. It could actually fall apart, or even be blown off the ocean floor. If it did close, the drill casing below it is also badly damaged, and could also blow out, forcing oil out the ocean floor.
The BOP is being used as well as it can right now, guiding oil to the surface. It can't be trusted to hold the pressure of a firm seal.

Thanks for all the responses... knowing a little more about the situation dosent make it any better... but helps with the frustration.

Fletcher

[CDave]

I watched on discovery channel last week and they said the seals were blown off on the safety BOP valves. I also watched an old show dated 1994 on the same channel which was about drilling in the North Atantic because the Gulf wells didn't produce that much oil(lol)... the BP well looks like a BIG winner.

The Gulf of Mexico is mostly natural gas. Which is used to heat homes, water heaters, stoves and used to run Power Plants that provide electricity to everything else. Plus it burns cleaner than coal.