Wear behaviour of coated sucker rod couplings

Abstract

Excessive wear of sucker rod couplings and oil field tubing can cause mechanical breakdowns in conventionally pumped oil wells, especially where sand particles contaminate the crude oil. To reduce the wearof the standard AISI 8630 steel couplings they are sometimes coated with hard spray metal particles. Such coatings add an extra expense and it is questionable whether the improved wear resistance of the coupling is justified, especially if it will result in increased wear of the softer oil well tubing. This paper evaluates three such coatings: nickel tungsten, nickel chromium, and titanium oxide. These are compared with an uncoated coupling in a water and a water–sand environment. An economic assessment of the wear results is also presented.