Cause analysis and prevention of sucker rod and tubing back off
Number of wells which are equipped by sucker rod pump units steadily increasing in most part of Western Siberia oilfields, due to passing to last or final stage of their usage. Accidents, first of all back off and parting of sucker rods and tubing, lead to significant increase of price of extracting oil. The reason of back off is torque which originates in string rods during it’s deformation under action of resistant forces against downward moving of plunger, “Lubinskii effect” and spatial curvature of borehole. As these factors can’t be eliminated during operating process, their action on threaded connection of sucker rods can be minimized by using of hinge joints. Increasing operability of sucker rods and tubing is possible by decreasing of torque, acting on breakout of threaded connection during operating process. The purpose is to reduce frictional torque in hinge, which is transmitting element of a string, with the help of constructive solutions. Relevance of back off problem is confirmed by oilfield data analysis. Analytically obtained constructive opportunities of reducing the torque, being transmitted by hinge. Hinge couplings which were made according to analytical investigations allowed to increase overhaul period up to two times.
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frictional torque; hinge; string rods; sucker rod; tubing; well sucker rod pump unit; момент трения; насосно-компрессорные трубы; скважинная штанговая насосная установка; шарнир; штанга; штанговая колонна References to this article (GOST) F.G. Khalimov, S.G. Zubairov, I.A. Salikhov, A.A. Kuramshin. Cause analysis and prevention of sucker rod and tubing back off // Electronic scientific journal "Oil and Gas Business". 2011. №6. P.457-462. URL: http://ogbus.ru/authors/Khalimov/Khalimov_1.pdf