Separating salt water from oil is not all that difficult. You might be surprised to know that most oil pumped from wells contains salt water that has to be separated, it's one of the things done by the holding tanks, allowing it to naturally separate in the field before being picked up and trucked off to a refinery. Speeding up the process with a centrifugal pump is a nice touch and would definitely be effective. The flow rates are so massive though we need a fleet of tankers equipped with these to literally suck up every acre foot of ocean water affected, process it and eject the 'cleaned' water. The logistics are rather daunting. I do agree with another commenter, we should have dropped a mini nuke down the hole to seal it when it first happened. It's not like the well couldn't be re-drilled.