The 15 psi Vacuum at U.S. EPA, Region IV

I will not obey the voices in my head.--Bart Simpson

Kentucky has not yet received primacy for the Underground Injection Control (UIC) program.  As a result, Kentucky is a direct implementation (DI) state with administration and enforcement of the UIC program resting with United States EPA Region IV in Atlanta, Georgia.  Having dealt with these folks since the very beginning of the program, I have seen some mighty peculiar things, but none more peculiar than the 15 pounds per square inch (psi) vacuum in EPA Region IV.

What follows is a portion of the body of a letter dated January 22, 1999, to a UIC permit writer at Region IV:

"Yesterday's mail brought copies of two draft UIC permits (KYI0719 and KYI0722) in response to recent FOIA requests.  Almost six years ago, this office first advised Region IV that the UIC permit "boilerplate" contained a silly error with respect to annulus pressure/vacuum.  Imagine my surprise when I discovered that Region IV persists in asserting that a 15 psig vacuum is possible on planet Earth.

"As you know, or should know, a 15 psig vacuum cannot be achieved on this planet where atmospheric pressure is only 14.7 psi at sea level (vacuum is merely the absence of atmospheric pressure and thus cannot exceed 14.7 psig).  This is not a trivial mistake; the result of this mind-boggling error which appears in all Region IV UIC permits, save two that I know of, is that no possible vacuum condition could trigger a 15 psig action threshold (since a 15 psig vacuum reading will never occur).  Stated otherwise, this incredibly stupid mistake completely negates the usefulness of annulus pressure monitoring in all cases where a loss in casing integrity results in negative pressure, not at all uncommon when tubing and packer are intact, but casing has failed."

If casing fails, but the tubing and packer remain sound, it is normal for wells with sealed casingheads to develop a negative wellhead pressure (vacuum) as a result of annular fluid level drop (the exception being a casing leak opposite an overpressured zone).  Region IV EPA has issued a large number of UIC permits that contain a negative wellhead pressure (vacuum) permit condition that can never happen.  Thus, no permittee under one of these poorly drafted permits would ever have to report a casing breach that resulted in a vacuum, no matter how bad, since said permittee would never and could never measure the prerequisite 15 psig vacuum required to trigger the cessation of injection and reporting requirements.

As of March, 2000, Region IV has done nothing to correct this error, except in a couple of cases.  Thus, Region IV remains the only place on earth where a vacuum greater than 14.7 psi can occur above sea level.

PS:  In late 2000, Region IV EPA began issuing UIC permits with a 13 psig trigger value, presumably in response to our pestering of them.  However, 13 psig vacuum is probably still too close to a perfect vacuum to be a useful figure.  That is to say, using 13 psig vacuum as a cease injection and reporting trigger will probably result in serious mechanical integrity problems never being reported or otherwise acted upon.  Strangely, Region IV EPA has used a five (5) psig vacuum action trigger in two UIC permits, but only two.

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