Improved Specifications for Manufacturing and Inspection of Sucker Rods

Abstract In an effort to reduce well failures, Mobil elected to investigate the reasons for rejection rates in new sucker rods. Independent third party inspections indicated a combined 14.3% rejection rate for new sucker rods from all manufacturers during 1990. Inspection results indicated a variety of rejects led to these failures. However, each manufacturer also had specific problems that led to the rejection of their rods (e.g. cracked pins, hardness variations, etc.). This paper presents the finding of laboratory analyses of certain sucker rod defects, as well as the resultant development of a comprehensive sucker rod specification. Results of comprehensive testing of new sucker rod boxes in accordance with API 11B are also presented and discussed.