Editing Well logging (section)

====Spectral acoustic logging====
Spectral acoustic logging is an acoustic measurement technique used in [[oil well|oil]] and [[gas well]]s for well integrity analysis, identification of production and injection intervals and hydrodynamic characterisation of the reservoir. Spectral acoustic logging records acoustic energy generated by fluid or gas flow through the reservoir or leaks in downhole well components.

Acoustic logging tools have been used in the [[petroleum industry]] for several decades. As far back as 1955, an acoustic detector was proposed for use in well integrity analysis to identify casing holes.<ref>Enright, R.J. 1955. Sleuth for Down-Hole Leaks, Oil & Gas J.:78-79</ref>
Over many years, downhole acoustic logging tools proved effective in inflow and injectivity profiling of operating wells,<ref>Britt E.L. 1976. Theory and applications of the borehole audio tracer survey, the SPWLA Seventeenth Annual Logging Symposium, Denver, Colorado</ref><ref>[http://www.onepetro.org/mslib/servlet/onepetropreview?id=SPE-162081-MS Spectral Noise Logging Data Processing Technology]</ref> leak detection,<ref>[http://www.onepetro.org/mslib/servlet/onepetropreview?id=SPE-161983-MS Leak Detection by Temperature and Noise Logging]</ref><ref>[http://www.onepetro.org/mslib/servlet/onepetropreview?id=SPE-161712-MS Innovative Logging Tool Using Noise Log and High Precision Temperature Help to Diagnoses Complex Problems]</ref> location of cross-flows behind casing,<ref>McKinley, R.M. 1994. Temperature, Radioactive Tracer, and Noise Logging for Well Integrity: 112-156</ref> and even in determining reservoir [[fluid]] compositions.<ref>Wang J, Alex van der Spek et al. 1999. Characterizing Sound Generated by Multiphase Flow, SPE Annual Technical Conference and Exhibition held in Houston, Texas</ref> Robinson (1974) described how noise logging can be used to determine effective reservoir thickness.<ref>Robinson W.S. 1974. Field Results From the Noise-Logging Technique, 49th Annual Fall Meeting of the SPE of AIME in Houston, Texas</ref>