2018004 INFLUENCE OF UNCONVENTIONAL METALLURGICAL VARIABLES ON MECHANICAL PROPERTIES OF API SUCKER RODS

Over 70% of the artificially lifted wells in the US are using sucker rod pumping systems. The sucker rod pumping system has been ameliorated during past years due to the high investment of companies and installers as performance of the sucker rod pumping system directly impacts production volume and consequently revenue of E&P companies. The sucker rod is one of the most vulnerable components of a sucker rod pumping system. The correlation between metallurgical variables and mechanical properties is of great importance to ensure proper functionality and to identify rod string optimization opportunities. The API 11B has classified different grades of sucker rods to aid the sucker rod utilization by operators as well as the standards for manufacturers. Corrosiveness of the wellbore fluid, well depths (loads), material susceptibility to H2S related cracking and other conditions are crucial to sucker rod’s continuous manufacturing improvement. A set of secondary or unconventional metallurgical factors have specific effects on mechanical properties that can aid in the sucker rod performance subject to these conditions. These factors are reviewed in this study along with its impact in the selection of suitable sucker rod grades to increase the life of sucker rod pump installations. This paper presents theoretical considerations and testing data to study metallurgical factors that affect the final mechanical properties of API grade sucker rods. Some of the metallurgical and mechanical variables testedand discussed include micro-alloying content, normalizing cooling rates, toughness and residual stresses developed at the steel mill and the sucker rod processing plant. Finally, an economical overview of these metallurgical and mechanical variables on different API grades are also discussed in this study.