I thought you agreed that I proved Campbell, Deffeyes, and Heinberg are "fucking idiots" for believing in the oil window and all of their other ridiculous beliefs.
ok here the quote you posted - lets tease it apart so you understand it
"Burying the sediments, or the oil, deeper than 15,000 feet continues the molecular breaking until the remaining product has only one carbon atom per molecule. That gas, almost pure methane (CH4) is often referred to as "dry" natural gas. The limit of 15,000 feet is the bottom of the oil window." -- Kenneth Deffeyes"
so first of all, what is the oil window? - its the range of depth at which oil forms -
http://en.wikipedia.org/wiki/Petroleum#Formation
Just forms - nothing else
No prediction about where oil can be found can necessarily be extrapolated from this - indeed to do so is to misunderstand the terminology and jump to aconclusion that is not supported by the facts.
As the oil itself can migrate in any direction through the rock,
and as rock strata can be re-shuffled or subducted to take the oil bearing rock to a different depth, it can therefore be found deeper.
Now beyond the oil window the oil will - as you rightly point out - be converted into methane - but like all geological processes this is slow - not instananeous.
Deffreyes even points this out in the quote by stating that oil
continues to be broken down
until the remaining product has only one carbon atom per molecule - thereby stating clearly that the process is not instantaneous.
It follows therefore that if we find oil beyond the oil window, it is not proof of an abiogenic origin, it is merely an oil reserve that has not yet fully converted into metane - indeed this is exactly what Deffeyes statement tells us.
Do you see now - references to the oil window related to formation - not where reservoirs can be found.
Scientific language is generally unambiguous, but it is nuanced - you need to learn to spot that nuance to interpret its true meaning.