seems to me, there’s room for more than one ‘straw’ in the opening of the well - so, why not keep adding more and more of those siphon pipes until the opening is filled with one big bundle of ‘straws’ leading up to the surface?
I guess it would be roughly the equivalent of lowering a paper clip into a shot glass from a third story window on a piece of sewing thread, using a couple of radio-controlled cars to help. Underwater currents will mess with the recovery string, much as puffs of wind would mess with the paper clip.
We initially heard numbers from 1000 to 5000 bbl/day, now they all are at the high end (better news copy, sells more soap). No one knows for certain, but a 2000 bbl/day recovery from the riser has to be making a difference. From there, the limitation is the ability to lift and process the fluid, separate the gas, and separate the oil from the water. Excessive 'suction' might collapse the riser pipe, leading to increased leakage where it would be harder to recover the oil. While a second ship might be able to take up some slack, bringing two ships close enough to try to tie in with another would not only tie up another drill ship, but risk yet another accident. Having multiple recovery strings (the oilpatch name for a long length of drill pipe 'joints' (a single, roughly 31 ft. section of drill pipe) all screwed together) would risk the recovery strings getting intertwined at depth, and inserting two different strings from separate sources would necessitate some very tricky maneuvering and coordination--and the release of more oil while that was taking place.
BP spudded the first relief well on the 4th of May, the second (backup) relief well on the 17th of May. The wells are projected to take 90 days from the spud date until they are complete, and target the original wellbore at 16000 ft. of depth.
While it takes longer, getting a drill bit in the close vicinity of the original wellbore is actually easier in some respects than the paperclip in a shotglass, but mechanical and other problems, running casing strings ('surface" and intermediate, Nippling up BOPs and such take a while, and it is pretty much guaranteed that BP and the drilling crews will be careful to not have a repeat of the incident they are seeking to remedy.
Were I BP, and expected to finish in 60 days instead of 90, I'd still say 90 days in case there was a problem in drilling the relief wells. If they said 60 days and it took 65, the press would eat them alive.
In the meantime, the riser recovery operation seems to be slowing the loss of oil to the environment.