I saw on TV this evening that BP is now setting about fitting a hose onto the leaking oil well. This slip-on hose arrangement is referred to as a lower marine riser package cap (LMRP); see information available at http://graphics.thomsonreuters.com/RNGS/2010/MAY/PIPE.jpg.
My intuition is that my own suggestion of plugging the riser with a self-weighted taper that could then be locked down (https://www.fun-engineering.net/blogs/funeng/2010/05/how-to-plug-a-leaking-oil-well-in-deep-water.html) would be a more satisfactory and safer arrangement. From what was described on TV, I thought the well riser had been intentionally severed just below the leaking blow-out preventer, but from the aforementioned graphical information at thomsonreuters.com it seems that this is not the case. If it were, then right now the well would be dischaging at full free-flow.
Once BP have the slip-on hose attached and routed to the surface they will have to keep taking up the full flow with tankers. Perhaps for BP that is an attractive option, because it will generate revenue. However, it seems to me that what the world needs right now is for this leaking well to be totally and securely plugged. If BP is capable of placing the LMRP cap on top of the stub coming up from the existing (leaking) blow-out preventer then it seems to me (perhaps naively) that it should also be capable of placing a new blow-out preventer on top of the existing blow-out preventer and subsequently using it to shut off the flow.
If no new blow-out preventer is to be inserted in conjunction with the slip-on hose then BP will be operating quite a precarious oil pipe that could rupture again in adverse circumstances. When operating with crude oil flowing through it, the pipe to the surface may not have enough self-weight to assure positive engagement with the stub at the ocean floor.
My idea of using a self-weighted taper would be capable of providing a more positive and secure shut-off. I realise, however, that it would be necessary to sever the well riser just below the blow-out preventer to insert it: any such decision should only be taken with extreme due diligence. I do not have enough information to visualise the actual situation: maybe the well riser is not accessible just below the faulty blow-out preventer. Apart from this, because of the force of the emerging oil, it just seems to me that it will be very difficult to place the LMRP. It is my hunch that a long taper could be inserted much more manageably, albeit into full free-flow from the well riser. Of course, any such idea should not even be begun to be physically implemented unless it had first been fully evaluated through computational fluid dynamics (CFD), as has been done by now, I presume, for the LMRP attachment process.
The more engineers who think about these things, and the possible consequences of various actions, the better.