@hamburgboy,
I suspect you are exactly right on the actual cost of gasoline at the pump.
I've never been involved in actual drilling operations, to say nothing of offshore operations, but I do have some familiarity with workover operations on the little oil and gas wells in this area. The blowout preventer is installed before work commences. It is removed when the job is complete. If the same procedure is followed in offshore drilling, the BOP is not an expense to an individual well.
I'm wondering about the incident, though. At one time, I read that the blowout was supposed to have been caused by poor cement, or poor cementing technique. If this is the case, I doubt any design of BOP would have helped. BOP has some control of what happens inside the casing. If the blowout is around the outside of the casing, but inside the well bore there is a different kind of problem. I am not at all sure which is the actual situation.