Drill pipe failure prevention-Corrosion protection with drill pipe surface coating and management of drill pipe use with fatigue database-

Drill pipe failure is a very serious problem for Teikoku Oil Company(TOC) to continue deep well drilling. Then TOC has continued to carry out research in order to avoid this trouble and started some innovative methods to cope with the drill pipe failure. This paper introduces the following methods. One is drill pipe coating with zinc plating on surface as corrosion victim. The other is drill pipe management by using drill pipe fatigue database. In this database, the amount of fatigue is calculated from cumulative degree of Von Mises Stress on drill pipe multiplied by its rotational time. Von Mises Stress is calculated from equation and rotational time is referred from past drilling record. It has not been concluded yet whether this database would show correct amount of drill pipe fatigue. However, TOC continuously needs to perform trial and error and achieve a proper drill pipe management method.