Method for compositely repairing scraped polish rod of pumping unit

Abstract

The invention relates to a method for compositely repairing a scraped polish rod of a pumping unit, and relates to the field of the manufacture of an oil field device. The method comprises the steps of washing, deoiling and derusting the scraped polish rod; selecting a repairable polish rod from the treated polish rods, carrying out the offset grinding repairing on a noncircular cross-sectional section of the repairable polish rod until the cross section is circular; carrying out filling repairing on a corroded surface of the polish rod; carrying out the delustering treatment on the surface of the repaired polish rod, and dotting and roughening the surface of the polish rod; nesting the dotted and roughened polish rod and a nickel-chromium alloy casing pipe, and carrying out the seamless rolling bonding on the polish rod and the casing pipe to obtain a finished product. By adopting the method, the scraped polish rod is reutilized, so that the production cost is saved; the outer casing pipe is compositely seamlessly connected with the polish rod, so that the strength of the composited polish rod is improved compared with the traditional polish rod; the casing pipe is made of the nickel-chromium alloy material, so that the corrosion resistance is high, the sealing effect is good, the service life of the polish rod is effectively prolonged, the replacement period of the polish rod is prolonged, and the manpower and production cost can be reduced.

Description

technical field [0001] The invention relates to the field of oilfield equipment manufacturing, in particular to a composite repair method for scrapped polished rods of pumping units. Background technique [0002] In the oil recovery of the oil field, in the late stage of production, with the continuous reduction of oil recovery, polymer oil extraction and ASP flooding are used to increase the oil recovery rate. However, although this method has greatly improved the oil recovery rate, there are a large number of ions in the produced fluid, which increases the conductivity, forms an oxygen concentration battery on the polished rod, and produces an electrochemical reaction, especially in the produced fluid. The chloride ions in the solution accelerated the corrosion rate of the polished rod, and its corrosion rate reached 1.2mm / a. The corrosion of the polished rod not only affects the normal production of the oil field, but also has the hidden danger of the polished rod breakin...

AI Technical Summary

Problems solved by technology

However, although this method has greatly improved the oil recovery rate, there are a large number of ions in the produced fluid, which increases the conductivity, forms an oxygen concentration battery on the polished rod, and produces an electrochemical reaction, especially in the produced fluid. The chloride ions in the solution accelerated the corrosion rate of the polished rod, and its corrosion rate reached 1.2mm / a. The corrosion of the polished rod not only affects the normal production of the oil field, but also has the hidden danger of the polished rod breaking, causing accidents such as shutdown and production stoppage, which seriously affects the oil field. Safe Production

In addition, the corrosion of polished rods also caused serious oil leakage at the wellhead packing, frequent replacement of packings, shortened the service life of polished rods, and increased the replacement of polished rods. It not only increases the production cost, but also brings difficulties to production management.

The scrapped polished rods that have been corroded and replaced cannot be used any longer, and can only be used after secondary repairs. The existing repair technologies are traditional leveling, filling and partial wear repairs. The service life of the repaired polished rods is also short, which cannot meet the needs of production. needs