GASM

Definition: 
Gamma Attenuation Saturation Monitoring
Subject Area 1: 
Reservoir Engineering & Reservoir Management
Remarks: 
Commonly used by BP, this uses doped oil or water phases to attenuate the energy of gamma rays that travel through the core perpendicular to the flood front. Each gamma source/detector pair measures the instantaneous water and oil, or gas and oil saturation averaged over a thin cross section of the core.