NOTCH - AND CORROSION - FATIGUE FAILURES IN DRILLING AND PRODUCTION MACHINERY.

In drilling and production oil well equipment both very heavy and pronounced internal pitting and severe external corrosion of the casing are encountered. In some cases, metal loss is negligible; however, in others such as in the presence of high cyclic stresses, corrosion fatigue failures are common in drill pipe, casing tubing and sucker rods. This research, therefore, covers corrosion failures in drill pipe, casing, tubing and sucker rods and the methods usually used to prevent them. In light of stress concentration factors a new design for spiraline casing and linear is suggested.