Abstract: Re-evaluation of completed wells is a good way to improve reserve and production in many oilfields,due to less investment,less risk and faster return.Application of logging technique in completedwell re-evaluation in the Tahe Oil Field achieved several good results:1)More producing formations,more potential and higher efficiency;2)Providing back layer and guiding completed region rolling deve-lopment;3)Exploring in upper layers of completed region and expanding petroliferous range.Mean-while,re-evaluation of completed wells indicated that the re-evaluation should expand to untargetedstrata as well as the surrounding area of the Tahe Oilfield.The identification methods of oil,gas andwater might be used to recognize and obtain more oil results.