Spectral Noise Log (SNL)

The Spectral Noise Log (SNL) is an advanced acoustic logging technique used to detect and characterize fluid movement, leakage, and behind-casing flow in oil and gas wells. The tool records acoustic noise generated by fluid flow and mechanical disturbances inside the wellbore and behind the casing.

Operating Principle

SNL operates by measuring acoustic signals over a wide frequency spectrum. Fluid movement through leaks, channels, perforations, or micro-annuli generates characteristic noise signatures. These signals are captured by highly sensitive acoustic sensors and analyzed in the frequency domain to distinguish between different flow mechanisms.

Advantages

• Accurate identification of active leakage points

• Ability to differentiate flow inside the casing from behind-casing flow

• No requirement for mechanical contact with the casing wall

• Applicable in both production and injection wells

• Can be performed under flowing and shut-in conditions