Review of downhole production logging instrumentation

State-of-the-art production logging instrumentation used to delineate downhole flow rate and fluid composition for two and three phase oil/water/gas wells is described. Various sensors are described, and the advantages and limitations of different tools are enumerated. The use of radioactive tracer flowmeters in injection and production wells is discussed. Classical techniques for interpretation of flowmeter data are described. The measurement of fluid density is accomplished using either a gamma-ray absorption or differential pressure device. Both types of instruments are discussed, including their advantages and limitations. Holdup measurements are required for full delineation of three-phase flow. Holdup is directly related to mixture density in two-phase systems, and is determined by measuring the dielectric property of a wellbore fluid sample. Several limitations of this measurement are discussed