posted on May, 16 2010 @ 09:34 PM
Actually putting a 4 inch pipe into the 21 inch pipe may be a very good idea.
They are dealing with a mix if oil and natural gas.
The natural gas is under high pressure and as it exits the 21 inch pipe and mixes with water it turns to Methane clathrate(methane ice)
Since there are other leaks in the pipe and when the try to pump the oil some of these leaks may draw in water forming Methane clathrate you want to
keep the pressure in the system high enough that this ICE does not plug the siphon tube.
When you decrees a pipe size with a set amount of gas flowing through it the speed of flow will increase and the pressure will increase and the
temperature will not drop.
This is what happened when they tried the containment dome.
as the gas exited the pipe the pressure dropped and the gas mixed with water forming Methane clathrate ice.
By not allowing the pressure to drop with the siphon system the ice will not form or because the gas is traveling at high enough speed through the
pipe it does not have a chance to build up on the inside of the pipe and block it.