PLA are really important for dynamic reservoir characterization process and support activities to improve the performance of a well. PL is an in-well logging operation designed to describe the nature and the behavior of fluid in, or around, the borehole during production, injection or shut-in conditions. We want to know, at a given time, phase by phase and zone by zone, how much fluid is coming out of or going into the formation. PL may be run for different purposes: monitoring and controlling the reservoir, analyzing dynamic well performance, assessing the productivity or injectivity of individual zones, diagnoses well problems and monitoring the results of a well operation (simulation, completion, etc).