Low-alloy steel resistant to carbon dioxide corrosion

Abstract

The invention relates to a low-alloy steel resistant to carbon dioxide corrosion, which comprises the following chemical components in percentage by weight: 0.20-0.35% of C, 0.10-1.0% of Si, 0.20-1.5% of Mn, 0.5-1.5% of Cr, being more than or equal to 0.35% of Ni, being more than or equal to 0.35% of Cu, 0.01-0.10% of Al, and the balance of Fe and inevitable impurities, wherein the total content of impurity elements is lower than 0.05 wt%. In manufacturing process of the alloy steel, heat treatment is not carried out after smelting, continuous casting, hot rolling and air cooling. The strength of the oil well pipe prepared by the alloy steel is 55 ksi, thus the oil well pipe prepared by the alloy steel is suitable for shallow wells resistant to carbon dioxide corrosion.

Description

technical field [0001] The invention relates to a low-alloy steel, especially low-alloy steel for carbon dioxide corrosion-resistant 55ksi steel grade oil well pipes and a manufacturing method thereof. Background technique [0002] During the development of oil and gas fields, CO 2 Corrosion is a significant and long-standing problem. From the perspective of material corrosion, for high CO 2 , Chloride ions, produced water, iron ion content, low PH value, and strong corrosive environment formed by high pressure and fluid erosion in the well. To ensure safe and efficient production in the oil field, the use of expensive super 13Cr stainless steel pipes is the most effective way. However, most oilfields in my country are lean ore and low-permeability oilfields, and the production life is relatively short, mostly less than 10 years. At present, ordinary carbon steel pipes are still used in the oil field, which has caused many serious CO emissions in the oil field. 2 Corrosio...

AI Technical Summary

Problems solved by technology

At present, ordinary J55 carbon steel pipes used in these shallow wells are prone to failure due to poor corrosion resistance under the compound acidic corrosion environment conditions containing carbon dioxide and chloride ions, which will lead to economic losses in oil fields.

[0007] At present, there is no anti-CO 2 55ksi steel grade economical tubing and casing products with corrosion effect and relatively simple production process

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