This story replaces an earlier item posted Mar. 6 on the same subject.
By OGJ editors
HOUSTON, Mar. 7 -- The US holds as much as 430 billion bbl of technically recoverable oil in a resource in place of 1.124 trillion bbl, according to the Department of Energy.
The volumes, reported in an update to a study released last month of several resource assessments, include speculative categories such as undiscovered oil, reserve growth, and a "residual oil zone."
DOE's study and update contain identical estimates for remaining oil in place.
The total in this category includes 293 billion bbl of light oil and 81 billion bbl of heavy oil. DOE estimates undiscovered oil in place at 360 billion bbl and says 210 billion bbl might be added to oil in place through "reserve growth," the increase in reserves estimates that occurs in some fields as development progresses.
To these components of remaining oil in place DOE adds 100 billion bbl from the residual oil zone, which it describes as oil in reservoirs below oil-water contacts, and 80 billion bbl from oil sands.
The study and update differ by 30 billion bbl in their estimate for the "technically recoverable resource" extrapolated from estimated volumes in place.
Both say conventional technology, which DOE describes as primary and secondary recovery methods, might recover 119 billion bbl from future discoveries and 71 billion bbl from volumes yet to emerge via reserves growth.
Enhanced oil recovery, according to the update, adds 240 billion bbl to the technically recoverable resource. That total includes 90 billion bbl added to discovered light oil and 20 billion bbl to discovered heavy oil.
In the updated estimate, EOR also adds to the technically recoverable resource 60 billion bbl from undiscovered volumes, 40 billion bbl from reserves growth, 20 billion bbl from the residual oil zone, and 10 billion bbl from oil sands.
In the original study's estimate of the technically recoverable resource, the value for light oil via EOR is 10 billion bbl lower than that of the update, and there is no estimate for residual zone EOR.