Method for generating chemical element co-permeation layer on surface of screw thread of petroleum casing coupling

Abstract

The invention discloses a method for generating a chemical element co-permeation layer on the surface of the screw thread of a petroleum casing coupling. The method comprises the following steps: lathing the screw thread for the coupling, putting a solid permeation agent containing B, Al and Ni into the coupling, sealing the two ends of the coupling, putting the coupling into a sealed permeation box, heating the permeation box in a heating furnace, permeating B, Al and Ni into the surface of the screw thread to form the co-permeation layer, and performing greasing protection, coupling marking, pressure test, corrosion prevention and packing on the coupling with the co-permeation layer. The method has the functions of corrosion resistance, wear resistance, no brittleness and bonding resistance; the frequency of using a petroleum casing is increased, the oilfield exploitation cost is saved, and the method has a very good promotion value.

Description

Technical field: [0001] The invention belongs to the processing field of metal steel pipes for petroleum development, and in particular relates to a method for forming a chemical element co-infiltration layer on the surface of a collar screw of petroleum casing. Background technique: [0002] At present, the main process steps commonly used in the processing of traditional couplings are: auxiliary measures such as threading (thread processing), inspection, marking, pressure test and protection for the couplings, and no special treatment for the threads of the couplings. Although the number of screw connections of imported couplings is better than that of domestic couplings, the actual working conditions of the couplings are harsh and the force is large. , The torque is large, and the screw thread will be worn and unloaded several times, causing failure phenomena such as sticking and buckling, which will affect crude oil production. [0003] The sticking phenomenon of the co...

AI Technical Summary

Problems solved by technology

On how to increase the number of couplings and threads that can be unloaded, which is a major problem that affects oil development and production, domestic and foreign experts and scholars have tried various solutions, such as improving the smoothness of the thread, changing the shape of the thread, galvanizing the thread, Copper plating, laser heat treatment (patent 02125747.1) and other technological methods have not been fundamentally solved, and improving the number of times of coupling and threading is still the bottleneck of oil development pipes