Decreasing Tubing Wear From Sucker Rod Coupling In Deviated Wells

In a reciprocating rod lift application, production tubing failure due to metal-to-metal contact with sucker rod couplings is a common problem in the highly deviated sections of the tubing string. The coupling is forced to be the point of contact against the tubing wall, which causes high friction and excessive tubing wear during the reciprocating motion. This excessive tubing wear typically leads to a hole in the tubing wall, resulting in high workover costs for the producer.  The coupling surface hardness, roughness, and coefficient of friction between the coupling and the tubing are all directly related to the resulting tubing wear generated at the contact region.  This paper intends to show through both in-house laboratory testing and preliminary field results that applying a lower friction coating to a sucker rod coupling decreases tubing wear and increases the life of the string.