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Underground Injection Control Branch Guidance No.: wy~yg://35/hup://www.epa.gov/reg5oh2duic/r5_OS.htm '~ _ ~ The interpretation and confirmation of the SAPT include: 1. Compazison of the pressure change through the test period to 3% of the test pressure (0.03 X test pressure). If the annulus test pressure changes by this amount or more (gain or loss), the well has failed to demonstrate MI (for all wells), and operation may constitute a violation of the UIC regulations. If the annulus test pressure changes by less than 3 percent (gain or loss) over the test period, the well has demonstrated MI, pursuant [0 40 CFR § 146.8(a)(1); and 2. Evaluation of the amount of liquid returned. If less than a cup of liquid is returned, the annulus m be blocked at a shallow depth. In the past criminal charges have been brought as a result of investigations inspired by the observation that very little liquid was returned. The following form can be used to find how much liquid should be returned: dV=(Pt-Pf)xVfxhx0.0000032 where: dV =the amount returned, gals; Pt =the pressure used to test the annulus, psi; Pf =annulus pressure after depressurization, psi; Vf =the volume of one foot of the annulus from Halliburton table 221-B, gals; h =length of the annulus, ft; and 0.0000032 gal./gal./psi =the compressibility of water. The result is [he number of gallons of liquid which should be returned. It is also the amount of lic needed to pressurize the annulus to the test pressure once the annulus is filled with liquid. Fora s annulus which might be typical of a Class II well (4-1/2 inch, 1 1.6 Ib/ft. casing and 2-3/8 inch tut pressurized to 300 psi), just under one half gallon of liquid should be returned for each 1,000 feet depth to the packer. [f several gallons of liquid are returned, it is fairly certain that the entire leng~ the casing and tubing have been tested. ATTACHMENT 2 STANDARD ANNULUS MONITORING TEST (SAMT) A. Basis The SAMT is essentially a continuing SAPT; however, interpretation is complicated by operatior effects, principally: 1) injection tubing expansion or contraction as a result of injection pressure changes and 2) well bore temperature changes associated with a) starting or stopping injection or daily and seasonal changes of injectate temperature. To eliminate additional complexities, the regulations now require that the pressure be greater than atmospheric pressure. This means that the annulus pressure should be raised to some pressure and the annulus should th be sealed. The pressure will change in response to temperature changes or even pressure changes the injection tubing. Allowing for some seasonal variation, the range of temperature change shou be consistent. In the event of a casing leak opposite a permeable zone, the pressure will normally probably to zero and, if not, the range of pressure change will be much diminished because the 9 of 34 528/99 I :09 PM