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Underground Injection Control Branch Guidance No. 5 <br />~~~ . :. i <br />w~yg://35/hltp://www.epa.gov/reg5oh?o/uic/r5 OS.htm <br />the test. Information which is helpful [o interpretation should be recorded on this form, including <br />a schematic drawing or description of the configuration of the tool, 2) the injection rate, 3) the tin <br />the beginning and end of each logging run, and 4) the time at which any peak is recorded. It is als <br />helpful to use time markers on the logs to accurately fix the times at which changes in radioactivi <br />are recorded. <br />Further testing may be necessary if possible migration out of an authorized injection interval is n< <br />This may include a series of time drives and slug chases to determine the extent of the leak or <br />channel. <br />D. Procedures for Running the Radioactive Tracer Survey (RTS) as a Demonstration of Pai <br />of MI <br />The demonstration can be effective for locating leaks in both the tubing and the casing. However. <br />RTS is useful for demonstrating an absence of leaks only in tubing strings through which the trac <br />material may flow. A demonstration [ha[ there are no leaks in the tubing requires that steps l thro <br />8 listed below be followed. To test the casing, the tubing may be removed and the same steps <br />followed, or [he packer may be unseated and the method used to check cement integrity, describe <br />Attachment ]0, may be followed. <br />Testing is always conducted while injecting, and the operator should ensure that adequate water c <br />be supplied for the test. The injection rate may be governed by the ability of the winch operator tc <br />track the RA slug as it moves downwazd. However, [he injection rate should be as close to [he <br />maximum injection rate as practical. The following practices usually result in interpretable result: <br />Ensure that [here is a significant pressure differential across the tubing wall to be tested. If <br />tubing is to be tested, special permission may be needed to perform the test with excess <br />pressure in the tubing, because permits may require a positive pressure differential within t <br />annulus. Although introduction of tracer material into the annulus can allow testing while <br />maintaining a positive pressure differential, testing within the range of USDWs defeats the <br />purpose of the positive pressure differential, because a casing leak would allow a release o1 <br />radioactive material into an USDW. Further, practical difficulties make testing with the tray <br />in the annulus a complex operation; <br />2. Set the gamma ray (GR) detector sensitivity so that lithologic effects are just identifiable, <br />usually 25 to 50 counts per second per inch. This ensures maximum sensitivity to leaked R <br />material. Noisy logs are much more difficult to interpret; <br />3. Make a background GR log over the interval to be tested before any RA material is introdu <br />into the well; <br />4. Record measurements over a period of three to five minutes with the tool stationary at two <br />points which are representative of the extremes of natural radiation within the interval to bl <br />tested. This will allow the interpreter to observe the effects of natural variations of GR <br />emission on the record; <br />Release a slug of RA material above the interval to be tested. The greater the intensity of <br />radioactivity of the slug the more resolution the method will have. DeFlections caused by tt <br />slug should be 50 times greater than those caused by lithologic effects; <br />14 0(34 5/28/99 1:09 PM <br />