One of the most bogus rules I have ever read. He obviously never worked Mississippi, Alabama, Louisiana, and East Texas and found the exact opposite to be true. Rarely, except for on some four-way anticlines, does any production occur below the pay in the field. You can look at any deep tails drilled on development wells and the mud logs rarely show anything more than a popcorn fart. It is about the timing of when the trap was in place and at what maturity the source rocks were. But if you want to try to round up some investors to pony up for an exploratory well into the bowels of the basement, then go for it. As Wallace Pratt so eloquently stated, "Where oil is first found, in the final analysis, is in the minds of men."
This rule is formulated as follows: "The most important of regularities that are observed in all oil-bearing areas, without exception, is that if oil or gas are present in one horizon, they will be present also at all lower levels, at least as traces of migration through the cracks." This statement is valid, whatever the composition of the rocks, the condition of their formation, (both metamorphic and crystalline rocks), and the content of organic matter in them. "At those levels at which there are good collectors and traps, accumulations of industrial interest may occur."