Coiled tubing resistant to corrosion of small amount of CO2 and H2S and manufacturing method thereof

Abstract

The invention discloses coiled tubing resistant to corrosion of a small amount of CO2 and H2S. The plate components of the coiled tubing include, by mass percent, 0.02%-0.08% of C, 0.15%-0.35% of Si, 0.4%-0.9% of Mn, 0.009% or less of P, 0.002% or less of S, 0.2%-0.6% of Cu, 3.0%-6.0% of Cr, 0.1%-0.25% of Ni, 0.2%-0.5% of Mo, 0.01%-0.04% of Ti, 0.015%-0.05% of Al, 0.02%-0.08% of Nb, 0.02% or less of Re, and the balance Fe and unavoidable impurities, wherein Re comprises La, Ce and Eu. By preparing a coiled plate, longitudinally shearing the coiled plate, carrying out lengthening through butt welding, forming and welding, finally, distressing treatment is carried out on welded seams and a tubing body, the coiled tubing resistant to corrosion of a small amount of CO2 and H2S is obtained. The CO2 corrosion resistance of the coiled tubing is three times or more that of ordinary C-Mn steel, the manufacturing cost does not exceeds 1.5 times that of common coiled tubing, and the coiled tubing is an economical coiled tubing product and can meet requirements of gas field development in the environment containing a small amount of CO2 and H2S.

Description

[0001] Technical field: [0002] The invention relates to the technical field of oil and gas pipes, in particular to a small amount of CO 2 and H 2 S corroded coiled tubing and method of manufacture thereof. [0003] Background technique: [0004] With the deepening of oil and gas field development, CO 2 and a small amount of H 2 The number of oil and gas wells in S is increasing, due to the CO in oil and gas wells 2 It dissolves in water to form a carbonic acid solution. Although carbonic acid is a weak acid, it is more corrosive than hydrochloric acid at the same pH value. If the well contains a certain amount of H 2 S, will cause strong corrosion to ordinary coiled tubing, high corrosion rate weight loss corrosion and localized corrosion, and even corrosion cracking, which will seriously affect the safe production of oil and gas fields and restrict CO 2 and a small amount of H 2 The development of oil and gas fields in S. [0005] Currently, for oil and gas field CO ...

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Problems solved by technology

[0007] The Chinese invention patent with the announcement number 101898295B authorized by the announcement on December 7, 2011, the patent name is a high-strength, high-plastic-toughness continuous pipe manufacturing method, the chemical composition of the material is: C: 0.05-0.12%; Si: 0.17~0.37%; Mn: 0.60~1.75%; P: ≤0.010%; S: ≤0.005%; Cr: 0.20~1.0%; Mo: 0.15~0.45%; Ni: 0.10~0.35%; %; Ti: 0-0.03%; Cu: 0.10-0.25%; Nb: 0-0.07%; Al: 0.02-0.04%; Ca: 0.002-0.004%; Coil slitting and butt welding, using steel strips to produce straight seam resistance welded steel pipes, which are produced by normalizing or quenching + tempering after welding; the materials in this patent have relatively high content of C and Mn, although it is helpful to obtain high-strength continuous However, the high content of C and Mn is easy to form banded structure and inclusions, which is very unfavorable to the uniform corrosion resistance, HIC and SCC resistance of the pipe; the addition of other alloy elements in this patent helps to improve the plasticity of the pipe, but it is not good for the pipe’s resistance to corrosion. The corrosion performance has no significant effect; the coiled tubing products produced by this patent contain a small amount of CO 2 and H 2 Working in the oil and gas well environment of S, it is prone to weight loss corrosion with high corrosion rate and stress corrosion caused by sulfide, which seriously affects the service life of coiled tubing and the safety of operation.

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