Abstract: Perforation failure on blind head of bottom exit pipeline of a FPSO flash tank A for production water occurred during service. Perforation causes of blind head were analyzed by macroscopic inspection, chemical composition analysis, metallographic examination, bacterial detection, scanning electron microscope and energy spectrum analysis. The results show that oil sands were deposited at bottom of the blind head. Inhomogeneous attachments on the inner wall of blind head resulted in local corrosion under depositions. Sediment deposition promoted SRB reproduction, and the erosion effect of bacterial corrosion products led to perforation failure of the blind head.