Spectral Noise Logging (SNL) can provide information on reservoir flow units behind one or multiple barriers, which is beyond the spinner capability. The SNL tool is designed to record a high-resolution noise pattern in a wide frequency range, normally generated by fluid or gas flowing through porous media and the wellbore. Noise pattern recognition is critical to differentiate between formation flow and wellbore flow.
SNL complements conventional production logging techniques by providing significant information that enhances reservoir flow characterisation. The tool design, data acquisition and advanced processing allow the location of active flow units and differentiation between flows through the reservoir matrix, fractures, high-permeability features, behind-casing channels and wellbore completion components.
Thorough analysis of active flow streaks helps to monitor sweep efficiency and identify bypassed oil regions.
Reservoir matrix flow noise remarkably correlates with porosity distribution. Therefore, it is an effective way to verify porosity and permeability models. This paper presents five field cases of SNL surveys performed during 2009–2011 in wells operated by Dubai Petroleum Establishment. These cases illustrate the allocation of injection by zone with rates below the spinner threshold, evaluation of the reliability of plugged perforations, and description of the behind pipe flow geometry. The paper also contains an introduction to SNL tool operation and noise data processing principles.