Noise logs are also used to evaluate fluid movement downhole. Unlike temperature surveys, noise logs are not run continuously across the interval of interest. Instead, a number of stationary readings are taken at different depths downhole. The movement of fluids, especially gasses, generates turbulence or noise, which gets louder as the flow rate or pressure drop increases. [[:file:production-logging_fig2.png|Figure 2]] shows how a noise log can be effective at detecting movement downhole. In this schematic diagram, a source, sink, and restriction to flow are the noise sources. The frequency spectrum of the noise is also observed to further improve the understanding of flow downhole. | Noise logs are also used to evaluate fluid movement downhole. Unlike temperature surveys, noise logs are not run continuously across the interval of interest. Instead, a number of stationary readings are taken at different depths downhole. The movement of fluids, especially gasses, generates turbulence or noise, which gets louder as the flow rate or pressure drop increases. [[:file:production-logging_fig2.png|Figure 2]] shows how a noise log can be effective at detecting movement downhole. In this schematic diagram, a source, sink, and restriction to flow are the noise sources. The frequency spectrum of the noise is also observed to further improve the understanding of flow downhole. |