HYDRO29443 - Laserfiche WebLink

Home Browse Search

Underground Injection Control Branch Guidance No. 5 wys g://35/hnp://www.epa.gov/reg5oh2o/uidr5_OS.hlm • withdrawal of liquids Operational Disadvantages Relative to Other Tests The W-BIT is approved only for Class III wells which cannot be tested by means of the SA o Requires use of a deadweight pressure gauge, which may be expensive [o acquire ~ Requires a 36-hour interval between initial and final pressure measurements C. Equipment and Forms A dead weight pressure gauges and an operator trained in its use are needed. A convenient works has been developed by members of [he Salt Institute. D. Procedures The UIC Branch has not identified any common errors in conducting the W-BIT, and we believe no additional guidance is needed beyond that provided in the Federal Register notices announcing approval. E. Interpretation The calculations which are pan of the test result in the calculation of a rate of pressure change. If pressure change is less than 0.05 psi/hr., then the test demonstrates the MI of the tested well. If th rate of change is more than the standard, the well lacks MI. ATTACHMENTS TEMPERATURE LOG (TL) A. Basis In almost every case, an aquifer into which water has flowed in the recent past is heated or cooler because the earth's temperature increases steadily with depth. This makes it unlikely that the ware moving into a reservoir is the same temperature as that which is displaced. Given sensors of sufficient sensitivity, the change in temperature is identifiable. In addition, the zone from which t water came is likely to be identifiable if flow is continuing. Temperature logs can also confirm th there is no flow of injectate through the rock surrounding the well bore and often will identify sm casing leaks. During injection the ability of the injectate flowing through the well to maintain its own tempera[ dominates all other effects so that the well must be shut in during temperature logging for the purpose of establishing MI. The principal requirement for conning temperature logs is [hat the we shut in long enough so that temperature effects related to well construction can dissipate, leaving relatively simple temperature profile. Experience has shown that 36 hours is usually sufficient in Region 5. In new wells, baseline temperature logs should be made as long as possible after drilling [he well before injection begins, because temperature effects due to circulation of drilling fluid will persis several weeks after drilling is completed and infiltration of drilling fluids causes temperature anomalies which may persist for several months. The existence of a temperature log which reflec I8 or 34 5/28/99 1:09 PM