And the key word is “thousands.” Kerogen in nature converts to oil under sufficient pressure and temperature. There is a temperature gradient as depth increases, using present horizontal drilling and fracking technology shale oil is now being produced around the world.
If in-situ heat was introduced at depths where the richest deposits are located and temperatures are already moderately high. It would not take that much to artificially tip the scales and create the process.
” using present horizontal drilling and fracking technology shale oil is now being produced around the world.”
I believe you are confusing “shale oil” with “oil shale”. “Oil shale” is kerogen. “shale oil” is crude oil that occurs in tight shale formations that is now being produced with horizontal drilling and stage fracking techniques.
I am not a geologist, but I am told that most oil was formed in shales which are rich in organic material, then over millions of years the oil migrated to sandstones and fractured limestones that were more porous and therefore easier to produce. That is what is referred to now as conventional oil that has been produced since Drakes well of 1859.
Only recently have we been able to economically been able to produce from the tight shales. This is what is going on now in the Balken shale of North Dakota and Montana as wel as the Eagle Ford shale in South Texas.
The Green River formation is an entirely different animal.
“And the key word is “thousands.” Kerogen in nature converts to oil under sufficient pressure and temperature. There is a temperature gradient as depth increases, using present horizontal drilling and fracking technology shale oil is now being produced around the world.”
I am not sure what the temperature gradient is in the Green River area, but I have worked on well up to 24,000 ft deep in the Oklahoma Anadarko Basin and the highest temp we encountered was 260F. That is quite a bit less than the 500 or more required for kerogen conversion, but maybe it would help.
Again the shale oil that is now being produced from shales around the world was exposed to enough temperature and pressure for a long enough time to make the conversion naturally. The Green River just never quite made the grade.
If there was crude oil (not kerogen) in the Green River formation at deeper depths we would already know about it. I am not sure what the thickness of the formation is, but I am sure they have drilled though it.