110Ksi grade CO2 H2S corrosion-proof oil well pipe and manufacturing method

Abstract

The 110ksi grade steel resisting CO2 and H2S corrosion for oil well pipe has the components including C 0.20-0.35 wt%, Si 0.10-1.0 wt%, Mn 0.10-1.0 wt%, Cr 1.0-2.5 wt%, Mo 0.1-1.0 wt%, Ni 0.10-1.0 wt%, Nb 0.01-0.1 wt%, Cu 0.10-1.0 wt%, Al 0.01-0.10 wt%, and Fe and inevitable impurities for the rest. It is produced through smelting, casting, cogging, rolling pipe, water or oil quenching at temperature over 850 deg.c, and high temperature tempering at temperature over 650 deg.c for over 2 hr. It has high CO2 and H2S corrosion resistance.

Description

technical field [0001] The invention relates to a low-alloy steel, especially a 758MPa (110ksi) steel grade anti-carbon dioxide and hydrogen sulfide corrosion oil well pipe with excellent SSC (hydrogen sulfide stress corrosion cracking) performance. Background technique [0002] CO 2 and H 2 S corrosion has been a major problem restricting the development of oil and gas fields for a long time. 2 and H 2 Ordinary carbon steel pipes or simple anti-sulfur oil well pipes are used in the S corrosion environment, which has caused many serious corrosion accidents in the oil field, resulting in economic losses and the protective measures taken for this have seriously affected the economic benefits of the oil field. [0003] At present, severe CO is common in most oilfields. 2 and H 2 S corrosion problem. And each year due to CO 2 and H 2 Accidents caused by S corrosion have brought economic losses of more than 100 million yuan to oil fields. From the perspective of anticorr...

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Problems solved by technology

However, in this patent, because no microalloying elements such as Nb and V are added in combination, the steel strength is low, and 758MPa (110ksi) steel grade products cannot be manufactured

[0005] The above-mentioned patented products are all due to low strength, which leads to the announcement of heat treatment tempering temperature, poor resistance to hydrogen sulfide stress corrosion cracking, and can only be loaded according to 80% of the nominal yield strength when the stress is loaded, so the product cannot be used in high hydrogen sulfide corrosion environments. oil and gas well

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