Welding method of sulfureted hydrogen resistant underground heat-insulated oil pipe

Abstract

The invention discloses a welding method of a sulfureted hydrogen resistant underground heat-insulated oil pipe, particularly suitable to the welding of a high-resistance sulfureted hydrogen underground heat-insulated oil pipe. The welding method comprises outer pipe pretreatment, inner pipe pretreatment, I end welding, pre-stress treatment and II end welding. A welding wire is selected form flux-cored wires and protective gas for welding is selected from mixed gas of high-purification argon and carbon dioxide; and after samples are welded, welding seams are subject to a sulfureted hydrogen resistant test. The welding method welds tubular products capable of adapting to sulfureted hydrogen corrosive wells; and the selected welding material and welding parameters ensure the strength, the compactness and the sulfureted hydrogen resistant performance of parent metals and the welding seams and can meet the using requirements. The components of the flux-cored wire change the physicochemical properties of arc atmosphere during welding, thus the splash is less, and splashed particles are fine and easy to remove. The welding protective gas not only has the characteristic of argon shieldedwelding, but also solves the problems of cathode migration, poor forming of air holes and the welding seams and the like generated during single argon welding.

Description

technical field [0001] The invention relates to a pipe welding process, in particular to a welding method for hydrogen sulfide-resistant downhole heat-insulating oil pipes, which is suitable for welding down-hole heat-insulated oil pipes, especially for welding 203CrMoCuTi highly hydrogen-sulfide-resistant downhole heat-insulated oil pipes. Background technique [0002] Insulated tubing is an important equipment used in the steam injection production process of heavy oil wells. It is used as a steam injection channel to inject high-temperature and high-pressure steam downhole, and protect oil well casing and cement sheath from thermal stress damage and reduce wellbore heat loss. , improve the effect of steam injection and oil recovery. [0003] Chinese patent 97115719.7 discloses a "vacuum heat-insulated oil pipe and its manufacturing technology". The forging machine is expanded into a bell mouth shape, and the size of the bell mouth is the same as the inner diameter of the...

AI Technical Summary

Problems solved by technology

The following problems of this technology need to be improved: 1. The steel grade used for the pipe is N80 steel grade that meets the requirements of the API 5CT standard, which does not have hydrogen sulfide resistance and cannot be used in hydrogen sulfide corrosion wells; 2. The welding wire used in the welding process of the heat-insulated oil pipe for CO 2 Solid core welding wire is used for fusion welding. The problem of solid core welding wire is that the chemical composition of the welding wire is not easy to adjust and the spatter is large during welding, which is prone to pores and affects the welding quality; Sensitive, prone to porosity during welding