Compressive forces causing rod buckling in sucker rod pumps and using sinker bars to prevent buckling

Sucker rod pumps has been the most commonly used pumps in the petroleum industry. Therefore, many studies associated with sucker rods focuses on maximizing the rod life. Rod buckling is a leading problem which causes concentrated wear on tubing wall, immediate failure in rod strings, and shortens fatigue life of the string. This study fundamentally consists of a review of the literature on compressive forces causing rod buckling in sucker rod pumps and using sinker bars to prevent buckling. The study initially addresses defining rod buckling, and then continues with the studies on analyzing the static forces acting near pump in the literature. Subsequently, the critical loads causing rod buckling, and the various approximations to estimate these critical loads are discussed. Then, the comparisons of the measured and calculated critical loads in the literature are presented. Next, the two of the most commonly experienced buckling types in the sucker pumps, sinusoidal buckling and helical buckling, are discussed. An example study on developing a model to estimate compressive forces acting on the pump plunger is reviewed to illustrate the importance of the parameters, such as surface roughness of pump, valve diameter, and pump geometry. Lastly, using sinker bar which is the most practiced method in the industry to prevent rod buckling is extensively discussed and demonstrated.