A Master thesis titled (The Petrophysical Characteristics Variation for Reservoir Units and Its Effect on Changing the Boundaries of the Oil-Water Contact of Mishrif Formation  in the Zubair Field ,Southern Iraq).  Hold at the College of Science, Geology Department. postgraduate Candidate Saad M. Al- eisaa demonstrates the most important objectives: Calculation of the petrophysical properties (porosity - permeability - water saturation) using different log, Evaluate the petrophysical properties of the formation, determine the performance of the reservoir units, and determine their thickness, extension and variance in the field of study.