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applicable UIC program becomes effective in the State) to conduct mechanical inte§rity tests and <br />provide the results to the Director. If a test indicated that a well did not have mechanical <br />integrity, i.e., it leaked injected fluids, the well would not be authorized for injection. For <br />existing-wells, the regulations require that mechanical integrity be demonstrated before <br />continued operation.of the well can be authorized. <br />The selection of a mechanical integrity test as a requirement of these regulations is <br />uniquely appropriate because normally wells cannot be inspected directly. Well integrity can be <br />demonstrated by the absence of a significant leak in the casing, tubing or packer and the absence <br />of significant fluid movement into an underground source of drinking water. The regulations <br />specify a choice of two tests to detect leaks, and two others to detect fluid movement.15 The <br />regulations specify monitoring of annulus pressure or pressure tests'with a liquid or gas for <br />detecting leaks, and use of noise or temperature logs for detecting fluid movement. Existing <br />Class II wells may use well records as proof of adequate cement to prevent fluid movement. <br />These tests are commonplace in the well injection, industry, and are considered reliable <br />indicators of mechanical integrity. 16 <br />The regulations also would allow the-use of mechanical text." To integrity tests not <br />specifically listed in the t use any of these tests, a Director would have to demonstrate its <br />suitability for the intended. purpose and secure EPA approval prior to its use. Once approved by <br />EPA, the test would be eligible for use by all persons unless specifically restricted. EPA allows <br />this flexibility because it recognizes that there may be mechanical integrity tests which, although <br />unspecified in the regulations, are fully adequate to detect well defects. Moreover, tests which <br />might be acceptable may be developed in the future. <br />The regulations further require that operators of wells which have been authorized for <br />injection under this program perform, additional,mechanical integrity testing at least once every <br />five years of operation for most wells." However, additional mechanical integrity tests for Class <br />III wells will only be required for those wells which are used for relatively long periods, such-as <br />salt solution and geothermal wells. Other Class III wells, which have a shorter life span, will not <br />be required to perform periodic mechanical integrity tests. In addition, Class lI wells may use <br />well records to demonstrate the presence of adequate cement to prevent significant fluid <br />movement. As part of an evaluation, a statistically valid random sample of wells will be tested <br />with either noise or temperature logs to assess the adequacy of well records as a measurement of <br />mechanical integrity. <br />is § 146.08(b),(c). <br />16 see generally, Mechanical Integrity Testing of Injection Wells. <br />17 § 146.08(d). <br />18 §§146.13(b),(3), 146.23(b),(3), 146.33(b),(3). <br />Page 9 of 20