McCabe, W.J. 1997 Wk57 tracer tests Wairakei 1991-2. Lower Hutt: Institute of Geological & Nuclear Sciences. Institute of Geological & Nuclear Sciences science report 97/14 8 p.
Abstract: As part of a comparative study of materials to be used for tracing the movement of gas and liquid in geothermal fields, a number of tests were made in the Wairakei field well WK57 during 1991 and 1992 using chemical, dye and radioisotope tracers. This report deals with the two radiotracer tests run in June and December of 1991 using iodine-131 and the third run in November 1992 using iodine-125. Tracer returns occurred and were measured in all the wells situated in the main production area south of the Kaiapo fault. Normalised peak concentrations were generally of the same order of magnitude as those measured in tests run from WK107 in 1978/9. There were however some strong and rapid responses, not observed in the earlier tests, which can be used to assess flow direction and speed in the vicinity of WK57. No significant returns were detected from wells on the north side of the fault. Other publications deal with the other tracers and the comparative results. (auth)