eliminating Failures in RRP Applications with KeBond Coated Endless Rod

Project Information

Client Name:	Confidential
Location:	Permian Basin, Texas
Application:	Corrosion
Initial Install Dates:	Bare ER October 09, 2023, KeBond ER December 18, 2023
Product(s):	ND Grade KeBond Coated Endless Rod (ER), 878 Taper

Client Challenge

Reciprocating rod pump (RRP) applications encompass a wide range of wellbore and operating conditions that can damage the rod strings and lead, in certain cases, to short-run failures. In the Permian Basin, the fluid conditions can result in rod corrosion, the wellbore tortuosity, high rod contact loads, and the combination of depths and fluid rates can also work to accelerate fatigue when corrosion is present. While Endless Rod (ER) provides many benefits in these applications including elimination of the connections and reduction of rod/tubing contact loads, its continuous contact with the tubing can wipe the natural and/or inhibitor induced protective layer from the surface increasing the potential for corrosion and wear.  

Nickel-Chrome-Moly steel in a lower strength (ND Grade) is typically recommended for mildly corrosive environments; however, in higher corrosion applications there is still the risk of premature failure due to corrosion-related fatigue. 

Figure 1 illustrates the surface pitting on the bare Endless Rod string caused by corrosive fluids which led to a short initial runtime of less than1 month due to corrosion fatigue.  

Client GoalS

Our West Texas client wanted to continue to use Endless Rod to realize its inherent benefits but needed a solution that would extend the historical bare Endless Rod run times. Performance would be considered a success if KeBond could, at minimum, double the previous runtime. In the case reflected in this study, runtime did not just double but surpassed previous runtimes by more than 12x.    

LS Solution

The solution proposed by Lifting Solutions was to replace the current ND grade bare string with a KeBond coated string of the same rod grade. KeBond Coated Endless Rod utilizes a 0.100in (2.54mm) thick, Polyketone blended thermoplastic coating that is extruded and attached to the bare steel rod using a proprietary manufacturing process. 

KeBond’s primary benefit is to act as a barrier coating protecting the Endless Rod body from wellbore fluids and their associated corrosion damage including conditions where there is inhibitor wipe. KeBond has also shown a lower coefficient of friction than bare steel which can reduce loads as well as reduce rod and tubing wear when subjected to similar deviated well conditions.     

Operational Results

In a Permian Well, where a bare Endless Rod string experienced a corrosion fatigue failure after only 22 days, the subsequent installation of a KeBond Endless Rod string has resulted in a runtime of over 460 days and is currently operating as of April 2025. The KeBond Endless Rod string configuration was identical. Other downhole and surface pumping equipment and operating conditions remained the same as shown in Figure 2.  

In terms of rod loading, while the KeBond string, due to its coating, was heavier by 1,197lbs, the measured peak polished rod loads were similar at 29,000 lbs likely due to reduced friction associated with the KeBond Endless Rod plastic on steel contact versus the previous bare Endless Rod steel on steel contact.  

KeBond provided a slight increase in max loading of approximately 100lbs, while also showing a slight increase in minimum load (Figure 3) which could indicate the rod string moving within the tubing which demonstrates less friction contact. Typically, reduced contact friction leads to reduced wear and increased run life which will be evaluated over time as the well is serviced and inspected. 

COnclusion

In deviated highly corrosive RRP well environments, Lifting Solutions KeBond Endless Rod provides barrier protection eliminating premature failures due to corrosion, increasing reliability, and extending run times relative to standard bare Endless Rod.  

Our client saw a significant improvement in runtime after implementing KeBond which has saved intervention and repair costs as well increased production by reducing downtime. Monitoring continues to assess the favorable impact of KeBond and the ability to reduce rod and tubing wear delivering further benefits in terms of reducing failures and equipment replacement costs.