Development of a new hollow sucker rod family for rotating pumping (progressive cavity pump systems)

• We develop a family of innovative products to be used for Progressive Cavity Pumping(PCP).
• These products are composed by tubes instead of solid rods.
• To join the tubes, a special threaded connection was designed.
• Theoretical work and experimental testing program were carried out.
• These products show better performance than API sucker rods for rotating pumping Systems).

Conventional solid sucker rods according to API 11B specification are widely used for rotating pumping, particularly to drive PCP Systems (progressive cavity pump systems) during the oil production. However, these products have been developed to work under axial alternating loads, and not under torsional loads. Thus, the use of these rods for rotating pumping has several limitations and disadvantages like a low yielding torque, insufficient backspin and fatigue resistance, showing low performance and resulting in high operative costs for artificial lift systems. Furthermore, the PCP System requires higher torque to work efficiently. For that reason, it is suitable to develop a new product with better performance to be used for this pumping system.This paper presents the development of a family of innovative products called “Hollow Sucker Rod” as a technical solution for PCP System. The development consisted of (i) design of the connection, (ii) manufacture of prototypes, (iii) full scale lab tests, and (iv) field trials.Some advantages of this new technology are: (i) high torque load to yielding, (ii) good fatigue resistance, (iii) high backspin resistance, (iv) less tubing wear, (v) increase in pumping rates, (vi) possibility to inject different kind of fluids by the inside of the “Hollow Sucker Rod”, and (vii) easy to make up and install (conventional pulling ring).