Abstract: Iraq's Rumaila Oilfield, located in the Persian Gulf Coast, features high underground water level and saline soils around crude oil tanks. The inner walls of tank bottoms contact with sludge and sewage, so both sides of the tank bottom are exposed to corrosive environments. Mismanagement in the past 20 years has led to damages to anti-corrosion facilities and coating, causing leakage in some tanks due to corrosion. To find out the reasons for corrosion-induced piercing in local crude oil tanks and define scientific and rational anti-corrosion measures, the tank bottoms in Rumaila Oilfield are investigated with respect to materials, local environment, storage media and corrosion morphology. For this purpose, methods including field survey and laboratory water quality/morphological observation and spectrum analysis are used. Finally, this paper proposes a restoration program and countermeasures to avoid corrosions inside and outside the tanks.