The upshot is that expected cash flow determines what areas will be drilled, not the size of potential reserves. Most companies won't drill a prospect unless they believe they can get their money back within two to three years, Doyle says. If it takes four or five years, the prospect is not very attractive. Cash flow is king.
It turns out that the NPV of the first three years of cash flow from my hypothetical well mentioned above is $1,556,112, only about half of the initial investment. Most companies would or should pass on such a prospect, and it would therefore never become part of anyone's reserves, he explains. Part of the hype over shale gas has to do with the claim that the wells may be very long-lived, he adds. Even if that turns out to be true--not a certainty as of now--the low flow rates expected after the initial burst of production and the distant payoffs would actually work against any decision to drill such wells. No wells, no reserves.
Doyle says that given modern technology, oil and natural gas are easier to find than ever before. But he doesn't believe that in North America at least, there is that much more to find. He thinks that shale gas in North America my indeed prove to be plentiful. But it will not be both plentiful and cheap.
And, of course, if we succeed at expanding natural gas production to meet the needs of a new natural gas-powered vehicle fleet--an idea advocated by one of the leading producers of shale gas--and expand other current uses such as the generation of electricity, we can expect that natural gas prices will soar. That may provide the necessary incentive (i.e. cash flow) to extract the shale gas that lies below the American landscape. But it will also certainly mean that the 100 years of supply that has been so frequently touted in the media will rapidly shrink to perhaps 30 or 40, and that the peak in production will come much sooner.
A peak in natural gas production in, say, 20 years would not exactly be a useful talking point for those advocating the wholesale conversion of key parts of the U. S. economy to run on natural gas. Just as we would be finishing such a conversion, we could find ourselves on the downslope of the natural gas production curve and faced with the urgent need to adapt our costly and newly completed natural gas infrastructure to run on some other energy source.