Here is a graphic that shows how the different categories of oil and gas relate to each other.
From most certain to least certain and then the total:
- Cumulative production to date
- Proved reserves
- Economically recoverable resources
- Technically recoverable resources
- Remaining oil and natural gas in-place
- Original oil and natural gas in-place
This illustration is from Technically Recoverable Shale Oil and Shale Gas Resources, from the U.S. Energy Information Administration.
Hat tip: The Million Dollar Way
Update: If you have any passing interest in what I say about the energy industry or oil or North Dakota, you really, really should be reading The Million Dollar Way regularly. If you landed here from the gracious shout-out over at MDW you already knew that. Mr. Oksol’s writing at that blog has provided a large portion of the learning I’ve gained on energy issues.