101 3. Acoustic logging • Acoustic measurements can be made in steel cased holes, when the casings are perfectly cemented. The presence of resonance phenomena due to poor cementation is used to evaluate cementation (cementation log). • Well conditions, in the case of poorly cemented cased wells, can make measurements difficult. The waves associated with casing vibrations must be filtered. This processing does not always allow the volume wave characteristics of the formation to be obtained, or the measurement of the formation’s parameters. • Acoustic measurements benefit from the use of long tools (3 to 4 m between the transmitter and the receivers). An operation may encounter difficulties if the lifting system is not high enough. If this is the case, the tool, if flexible, can be bent before being introduced into the well. The tool can also be introduced using constituent parts that can be connected to each other. References Arditty P.C., Arens G., Staron P., 1984, Improvements of formation properties and evaluation through processing and interpretation results of the EVA tool records. SEG 54th Annual Meeting expanded abstracts. Biot M.A., 1956, Theory of propagation of elastic waves in a fluid-saturated porous solid: I - Low waves in a fluid-saturated porous solid: I - Low frequency range; II - Higher frequency range. The Journal of the Acoustical Society of America, 28, 2, pp. 168-178 and 179-191. Cheng C.H., Toksöz M.N., 1981, Elastic wave propagation in a fluid-filled borehole and synthetic acoustic logs. Geophysics, 46, 1042-1053. Coppens F., Mari J.L., 1995, Application of the intercept time method to fullwave form acoustic data. First Break, 13: 11-20. Fortin J.P., Rehbinder N., Staron P., 1991, Reflection imaging around a well with the Eva full-waveform tool. The Log Analyst, 32, 3, 271-278. Gardner G.H.F., Gardner L.W., Gregory A.R., 1974, Formation velocity and density. The diagnostic basis for stratigraphic traps. Geophysics, 39, 770-780. Gaudiani P., 1982, Acoustic coring in granite with a small diameter logging tool. Proceedings, Workshop about geophysical investigations in connection with geological disposal of radioactive waste, Nuclear Energy Agency Organization for Economic Cooperation and Development, Ottawa: 157-171. Kaneko F., Kanemori T., Tonouchi K., 1990, Low-Frequency Shear Wave Logging in Unconsolidated Formations for Geotechnical Applications. Geophysical Applications for Geotechnical Investigation, ASTM STP 1101, F.L. Paillet and W.R. Saunders, Eds. American Society for Testing and Materials, Philadelphia, pp. 79-98. Mari J.L., Gavin P., Coppens F., Wicquart E., 1992, Traitement des diagraphies acoustiques. Éditions Technip, Paris.
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