A Study of Inspecting the Stress on Downhole Metal Casing in Oilfields with Magnetic Memory Method

摘要

This paper introduces a surface experimental model machine of metal magnetic memory inspection(MMI) which is co-developed by Daqing Logging & Testing Services Company (DLTS) and EDDYSUN Company(Xiamen).The model machine is compared with the instrument which was introduced from Russia and an experimental study of casing enforcing inspection on 25 casings is carried out with the finding of good corresponding relationship between the stress on casing and the information of magnetic memory. It provides a criterion of four-class semi-quantitative evaluation on the casing stress distribution. On the basis of this, a model machine of down-hole 8-electrodes inspecting the metal casing magnetic memory is developed and field test has been done successfully. It provides the basis for overcoming the difficulty of evaluating the downhole casing and tubing lifetime in the oilfield and for putting this model in to commerce in the future.