ROCKMAN wrote:Companies like BP do annual assessments of global petroleum resources...". Yes, but only for identified reservoirs. For instance, consider African country X: if none of its shale formations (remember the vast majority of sedimentary formations in the world are shale) have been evaluated for their hydrocarbon potential then no estimate can be made of its (possible) hydrocarbon yield.
Actually, the big oil companies aren't like librarians who only care about collecting information on existing oilfields. Quite the opposite. Part of the reason why major oil companies like BP do annual assessments of global petroleum resources is to identify potential exploration targets with significant petroleum resources that haven't been developed yet. This information is usually not released publicly, i.e. it is held as proprietary to the oil company and used to target future exploration targets.
I repeat----the oil majors are definitely NOT doing these global annual assessments just to tabulate existing oilfields. The annual assessments of global oil resources done by the oil majors are part of the process used to identify new targets for their global oil exploration programs.
.....the exploration geologists and geophysicists seem pretty sure we'll get unconventional oil from shale about a kilometer down.....I sure hope they're right.....I got to see this process in action when I worked for Chevron. It struck me then how Big oil companies are like top predators in the animal world......first they spot their prey (potential oil fields) by doing annual global assessments to locate new exploration targets.....then they stalk their prey (i.e. oil) by getting preliminary permits and sending out preliminary reconnaissance and exploration teams.....and then they kill their prey and eat it, i.e. they sign longterm leases and then they test drill and do step out wells and then they go into production.
One of the most important reasons for doing global reviews is to identify countries and regions with shale formations etc. that might be large sources of unconventional petrloleum, but that haven't been fully evaluated for their hydrogen potential. Only after large potential targets are identified will oil majors then do what is called "EXPLORATION"...i.e. they send teams of geologists and geophysicists to evaluate the petroleum potential. The Big oil companies won't waste their time on little fields. Only after a large prospective target is identified and the preliminary exploration work is done will the oil companies move onto leasing and full development, i.e. even before any drilling is done they have made an estimate of how much unconventional oil the field might hold, so in actuality estimates of potential oil resources for undeveloped shale basins are made all the time.
AND, don't forget there are independent global resource evaluation programs being run by government agencies like the USGS who are also busily looking into prospective unconventional oil fields in to estimate the GLOBAL potential for future unconventional oil production. I linked to the USGS estimate of the amount of unconventional left in the world in my post above. The whole point of the USGS estimate of global potential unconventional oil resources is to include fields that haven't yet been drilled and aren't yet producing oil....i.e. they are attempting to estimate how much unconventional oil remains to be produced on our planet, including oil from areas that haven't been developed yet. Clearly their estimates for undeveloped fields aren't going to be as good as for developed field, but its not rocket science for an USGS science team to document the stratigraphy of sedimentary basins and then sample the shale rocks for oil content in order to estimate the potential oil resource even before any drilling and development is done. Let me give you an example of the one of these programs: for years the USGS has had a program mapping Saudi Arabia for petroleum potential, and part of this program involves making estimates of petroleum resource potential to help guide future development. These estimates were all made BEFORE drilling and development occurred. Now---of course there are many examples of conventional oil fields being drilled without finding any oil, because the oil has leaked out. But with unconventional oil and shale oil this usually isn't a problem.....the oil in tight shale is almost certainly going to be there when you drill it. The actual amount of oil may vary slightly due to local lithological and thickness variations in the shale, but your chances of finding oil EVERYWHERE in an oil-rich oil shale are really very very good.
Cheers!