Gentlemen,
There's lots of oil left in the GoM and at $50.00 a barrel it's well worth the expense of going after it. However, as the saying goes, "it takes money to make money." Some of the major oil companies which are in a favorable financial position are now divesting themselves of their older close-in properties and constructing newer technologically advanced facilities in deep water which consolidate and automate the production and transportation of oil and gas to a much greater degree. With modern technology a single platform can now service dozens of individual wells. These facilities can be serviced efficiently by larger aircraft without the need for a "field ship."
The 30-40 year-old fields of multiple individual wells are gradually being left to the smaller operators. The facilities are in many cases run down and use older technology and techniques which produce oil and gas much less efficiently. To bring these fields up to modern standards would be economically unfeasible. Thus, while these fields can still be made to turn a profit, it often requires cutting corners - something the majors have found to be fiscally detrimental (read unacceptable liability) in the long run. The majors are in effect transferring the risk to the smaller operators whose pockets are not quite so deep. However, as long as the smaller operators can continue to squeeze a few dollars out of the old properties they will perpetuate the higher risk operations.
I don't disagree that the single-engine small ships are the preferable aircraft for field work, but hopefully, field work is becoming a thing of the past. For you see, no matter how statistically safe the aircraft, 50-75 landings in a day exposes a pilot to a relatively high level of risk. If you eliminate the need to make that many landings each day by consolidating your facilities you've obviously reduced that risk. I don't see it changing overnight, but I suspect that as operating costs rise, even by cutting corners, the older facilities will eventually (for instance when the price of oil drops) become unfeasible and will be abandoned. The GoM will then be in a position where operators are driven by economics to multi-engine multi-pilot aircraft with all the attendant safety enhancements.
-Stan-