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~~~. UNITED S~ES ENVIRONMENTAL PROTECT AGENCY <br />_,,,..r ~ REGION VIII <br />999 18th STREET -SUITE 500 <br />DENVER, COLORADO 80202-2466 <br />STEP-RATE TEST PROCEDURE <br />January 12, 1999 <br />PURPOSE: <br />The purpose of this document is to provide a guideline for the acquisition of a Step Rate Test <br />(SRT). These procedures are consistent with acceptable oilfield practices. Test results may be <br />used by the EPA to determine a Maximum Surface Injection Pressure (MSIP) to provide for the <br />protection of the underground sources of drinking water at an injection well having mechanical <br />integrity. Attached is a form that you may copy and use to record step rate test data. <br />Step rate test results must be documented with service company or other appropriate <br />(acceptable) records and/or charts, and the test should be witnessed by an EPA inspector. <br />Arrangements may be made by contacting the EPA Region 8 Underground Injection Control (UIC) <br />offices using the EPA toll-free number 1.800.227.8917 (ask for extension 6137 or 6155). <br />STEP-RATE TEST PROCEDURE: <br />1) The well should be shut in long enough prior to testing such that the bottom hole pressures <br />approximate shut-in formation pressures. If the shut-in well flows to the surface, the <br />wellhead injection string should be equipped with a gauge and the static surface pressure <br />read and recorded. <br />2) A series of successively higher injection rates are determined using guidelines below, and <br />the elapsed time and pressure values are read and recorded for each rate and time step. <br />Each rate step should last exactly as long as the preceding rate. If stabilized pressure <br />values are not obtained within the rate steps suggested below, the test results may be <br />inconclusive. <br />Formation Permeability lmd) <br />s 5 and <br />z ZO and <br />Tota! time per rate-step (min) <br />60 min <br />30 min <br />3) Suggested injection rates: <br />5~ i <br />10~, , <br />20~ 11 <br />40~ f Of Anticipated Maximum Injection Rate <br />60~ . <br />80,E <br />100 1 <br />4) Injection rates should be controlled with a constant flow regulator that has been tested prior <br />to use. A throttling device is not sufficient. <br />Pimtsd on Recycled Popp <br />1 <br />