Are you writing about in situ production or recovery from tar sands / oil shales that have been mined? Also you use the phrases "90%" and "no measurable trace" in the same sentence.
I admit that I am no expert, but knowing a bit about the competitive nature of the small producers, if there is any patentable process involved, there would be little difficulty lining up test wells and eager licensees. If there is nothing that can be patented, then I am curious as to why this has not "leaked" into the public domain.
BTW, I am aware that it took a very long time for "polymer jobs" to go from the lab to general use in the field. However, this sounds too good to have that sort of a gestation period.