Stainless steel for oil well pipes with microbiological corrosion resistance and preparation method thereof

Abstract

The invention aims to provide a stainless steel for oil well pipes with microbiological corrosion resistance and a preparation method thereof, in order to reduce the risk of microbiological corrosionat the aspect of materials. The stainless steel comprises the following chemical components by weight percent: less than or equal to 0.03% of C, 0.1-0.3% of Si, less than or equal to 0.5% of Mn, 12.0-14.0% of Cr, 4.0-6.0% of Ni, 1.5-2.5% of Mo, 1.0-2.0% of Cu, 0.1-0.8% of Ga, 0.1-0.2% of Ce, less than or equal to 0.02% of S, less than or equal to 0.03% of P and the balance of Fe and inevitable impurities. According to the invention, a defined amount of Cu, Ga and rare earth element Ce are compounded and added on the basis of traditional super martensitic stainless steel components for oil wellpipes, so that the stainless steel can acquire higher toughness and excellent property for resisting against hydrogen sulfide stress corrosion cracking under the synergistic effect of the three elements, and meanwhile, the stainless steel has excellent microbiological corrosion resistance and can be applied to the production of steel used for oil well pipes.

Description

Technical field [0001] The invention relates to a stainless steel for oil well pipes and a manufacturing method thereof, in particular to a stainless steel for oil well pipes with microbial corrosion resistance and a manufacturing method thereof. Background technique [0002] Microorganisms are an important factor in initiating and accelerating metal corrosion. The loss caused by microbial corrosion accounts for about 20% of the total metal corrosion. Reports have shown that 75% of the corrosion in 13Cr super martensitic stainless steel used in oil wells and 50% of the failures in pipeline steels above X65 grade for underground pipelines are due to microbial corrosion. In the oilfield water injection system, the growth, metabolism and reproduction of sulfate reducing bacteria (SRB), iron bacteria, saprophytes and other microorganisms can cause serious corrosion of drilling equipment, water injection pipelines and other metal materials, and block pipelines and damage The oil laye...

AI Technical Summary

Problems solved by technology

In the oil field water injection system, the growth, metabolism and reproduction of sulfate reducing bacteria (SRB), iron bacteria, saprophytic bacteria and other microorganisms can cause serious corrosion of drilling equipment, water injection pipelines and other metal materials, and block pipelines and damage oil layer, causing water injection, oil production, and oil and gas quality to decline, and also brings serious difficulties to crude oil processing

At present, the microbial corrosion protection of oil well pipes has not been paid attention to in China, and most of them are concentrated in CO 2 Corrosion, H 2 S-induced stress corrosion and Cl - Induced Localized Corrosion Protection Studies

However, the stainless steel used for oil well pipes that have been in service or existing has not considered the performance of the material itself to resist microbial corrosion, both in terms of chemical composition and production process.

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