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~~~ UNITED STS ENVIRONMENTAL PROTECTI~ AGENCY <br />`w ~ REGION VIII <br />~~ ~$ 999 18th STREET -SUITE 500 <br />v~g~',_O DENVER, COLORADO 80202-2488 <br />RADIOACTIVE TRACER SURVEY <br />January 22, 1999 <br />PURPOSE: <br />The purpose of this document is to provide a guideline for the acquisition of a radioactive <br />tracer survey (RATS), a procedure that may be used to determine whether injected fluids may <br />migrate vertically outside the casing after injection. This guidance may be used to develop a well• <br />specific survey plan that accounts for specific well construction and operation considerations. Prior <br />approval of planned RATS procedures by EPA is strongly recommended. <br />Radioactive Tracer Survey results must be documented with service company and other <br />appropriate log records and/or charts, and the test should be witnessed by an EPA inspector. <br />Arrangements may be made by contacting EPA Region 8 Underground Injection Control (UIC) <br />offices using the EPA toll free number 1-800.227-8917 (ask for extension 6155 or 6137). <br />RECORDING GUIDELINES <br />The logging must be done while the well is injecting at normal injection pressure and rate. The <br />pressure and rate should be brought to equilibrium conditions prior to conducting the survey. <br />The survey tool must include a collar locator for depth control, an injector, and two detectors (one <br />above and one below the injector). <br />Vertical log scale may be one inch, two inches, or five inches per 100 feet. <br />The Gamma Ray log may be run at up to 60 feet per minute (ft/min) at a time constant (fC) of one <br />second, or up to 30 ft/min at a TC of 2 seconds, or up to 15 ft/min at a TC of 4 seconds. The <br />logging speed and time constant used must be indicated on the log heading. <br />The horizontal log scale must be recorded in standard API Units (or in counts per second). <br />The gamma ray (GR) sensitivity must be set so that the tracer will be obvious when detected and <br />will not be confused with normal "hot spots" in the logged formations (e.g., the gamma ray <br />sensitivity set so that the lithology can be correlated by recording a "base log"). <br />Record the beginning and ending clock times of each log pass. <br />Record the injection pressure and rate during each log pass. <br />Record the volume of fluid injected BETWEEN log passes. <br />Record the type, volume, and concentration of each tracer "slug" used. <br />Show the percentage of fluid loss across the pertorated interval(s). <br />~/ a~;,,me o~ a~aca.~. <br />