METHOD FOR PUMPING ROD CONNECTION BY FRICTION WELDING

Abstract

The current stage of development of the Russian oil industry is characterized by the transition of fields to a late stage of development, a decrease in the rate of oil production and an increase in the proportion of marginal wells, the main method of operation of which is traditionally the installation of a ucker rod pump (ISRP). One of the elements of the ISRP, leading to frequent failures, are the sucker rods. The most widespread are forged rods, in which the head is formed by high-temperature upsetting. The disadvantage of this method is the frequent misalignment in the process of planting the head on the rod body, which, when the rod string is operating, causes additional vibrations, leading to high bending cyclic loads in the fillet part and, as a consequence, failure and breakage of the rods. In addition, in the process of head upsetting, accompanied by high-temperature impacts, the microstructure of the metal changes, and the interface between the structures, as a rule, a fillet, is often a break point due to the emerging stress concentrator. The objective considered in the article is to improve the technology for manufacturing rods by eliminating misalignment of elements connected by friction welding and increasing the reliability of the welded joint by increasing the area of the surfaces to be welded. The objective posed is proposed to be solved by the fact that the method of manufacturing sucker rods, including rolling a bar, its machining, processing on a straightening-polishing machine, manufacturing a separate threaded head with a rolled thread on it and connecting it to the rod body by friction welding, implies that the threaded the head and end of the rod body are tapered; the protruding truncated conical end of the rod body is inserted into the tapered recess of the threaded head, while the length of the truncated conical end of the rod body should be less than the length of the tapered recess of the threaded head. This article discusses a method of connecting the rod body and the rod head by friction welding, which avoids the head upsetting process. This ensures the alignment of the sucker rod, which could not be achieved by head upsetting, which minimizes vibrations in the string and increases the overhaul period of the pumping equipment. In addition, the process of their manufacture is simplified, which leads to a decrease in the prime cost of the rods.