Sucker Rod Antibuckling System: Development and Field Application

Abstract

When the oil price is low, cost optimization is vital, especially in mature oil fields. Reducing lifting costs by increasing the mean time between failure and the overall system efficiency helps to keep wells economical and increase the final recovery factor. A significant portion of artificially lifted wells currently use sucker rod pumping systems. Although its efficiency is in the upper range, there is still room for improvement compared with other artificial-lift systems. This paper presents the field-tested sucker rod antibuckling system (SRABS), which prevents buckling of the entire sucker rod string, achieved by a redesign of the standing valve, the advantageous use of the dynamic liquid level, and, on a case-by-case basis, application of a tension element. The system allows full buckling prevention and a reduction of the overall stresses in the sucker rod string. The resulting reduction in the number of well interventions combined with the higher system efficiency prolongs economic production in mature oil fields, even in times of low oil prices. The analysis of SRABS, using finite-element simulations, showed a significant increase in system efficiency. The SRABS performance and wear tests under large-scale conditions were performed at Montanuniversität Leoben’s Pump Test Facility and in the oil field. The results of intensive laboratory testing were used to optimize the pump-body geometry and improve the wear resistance by selecting optimal materials for the individual pump components. The ongoing field-test evaluation confirmed the theoretical approach and showed the benefits achieved by using SRABS. SRABS itself can be applied within every sucker rod pumping system; the installation is as convenient as a standard pump, and manufacturing costs are comparable with those of a standard pump. This paper shows improved performance of the SRABS pumping system compared with a standard sucker rod pump. SRABS is one of the first systems that prevents the sucker rod string from buckling without any additional equipment, such as sinker bars. Testing of SRABS has identified significant benefits compared with standard sucker rod pumps.