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Underground Injection Control Branch Guidance No. 5 I~r • w~wyg://35/http://www.e pa. gov/reg5oh2o/u is/r5_O5. h tm CEMENTING RECORDS A. Basis A very small span of sound cement surrounding the casing will prevent movement between the w bore and the casing or between casings. The use of cementing records as a demonstration of part 2 of MI is limited to all Class II wells an those Class III wells in which the nature of the construction precludes the use of temperature or n logs. The cementing records must indicate that cement is present along the well bore between [he injection zone and the base of the lowermost USDW. B. Advantages and Disadvantages Informational Advantages Relative to other Demonstrations none Informational Disadvantages Relative to Other Demonstrations This is an indirect demonstration. The presence of cement does not assure us that it is spun Onerational Advantages Relative to other Demonstrations Usually based on existing information A one-time demonstration Operational Disadvantages Relative to Other Demonstrations ~ If paper records are not available, they cannot be reconstructed ~ Either the CBL or CET requires that the well bore be water filled to the upper limit of the logged interval C. Equipment and Forms Forms of Cementing Records Cementing records include any acceptable records containing information which allows the calculation of cement placement behind the casings of wells. Cementing records may include cen bond logs, cement evaluation logs, and temperature logs which give evidence of the location antL quality of cement along well bores. The most reliable cementing records are job reports from cementing companies, but any records of construction containing information about the placemer cement may be acceptable. Either the original or copies of these cementing records must be submitted. Cement Bond and Cement Evaluation Loes Cement bond logs (CBEs) use sonic attenuation and travel time to determine whether casing is cemented or free. The more cement which is bonded to casing, the greater will be the attenuation sounds transmitted along the casing. The Cement Evaluation Tool (CET) operates on a principle similar to the CBL except that the tool uses many sound transmitters and receptors to evaluate the cement in various sectors of the well bore. Instead of an average bond index accounting for the et circumference of the well bore, the log can identify poor bonding in single 60o segments. This increases the ability to confirm the presence of channels tremendously. The logs should include a gamma ray curve, casing collar log, acoustic amplitude and travel time 30 0(34 5/28/99 I :09 PM