An economical rare earth-containing 80ksi steel grade anti-hydrogen sulfide corrosion and anti-collapse oil casing

Abstract

The invention discloses an economical rare earth-containing 80ksi steel grade anti-hydrogen sulfide corrosion and anti-collapse petroleum casing, which comprises the following chemical components in mass percentage: C 0.25%-0.30; Si 0.20%-0.30%; Mn 0.50% ~0.60%; P≤0.010%; S≤0.005%; Cr 0.60%~0.70%; Mo 0.10%~0.20%; Al 0.010%~0.030%; RE 0.0005%~0.0020%; its unavoidable impurities. Methods for their preparation are also disclosed. The object of the present invention is to provide an economical rare earth-containing 80ksi steel grade hydrogen sulfide corrosion-resistant and anti-collapse oil casing with low production cost, low inclusion content, high dimensional accuracy, and good matching of strength and toughness, and a preparation method thereof.

Description

technical field [0001] The invention relates to the fields of ferrous metal smelting and metal pressure processing, in particular to an economical 80ksi rare earth-containing steel grade that is resistant to hydrogen sulfide corrosion and collapses. Background technique [0002] At present, the exploitation conditions of my country's oil and gas fields are becoming more and more complicated. The southwestern oilfields, the western oilfields and the offshore oilfields with high temperature, high pressure and buckling deformation have been put into development one after another, and the domestic demand for high collapse-resistant casing is also increasing. The selection of high-collision-resistant casing, on the one hand, satisfies the casing collapse performance requirements of oil and gas wells in plastic flow formations such as salt rock, salt gypsum rock, soft mudstone, high formation pressure or abnormal in-situ stress, and improves the performance of the casing. Safety; ...

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Problems solved by technology

[0004] Document 1 is an 80ksi steel grade hydrogen sulfide stress corrosion resistant petroleum casing and its manufacturing method (patent application number: 201310150513.6). Contains precious elements Nb and V, and the product is mainly designed for hydrogen sulfide corrosion resistance. Therefore, the casing product patented in this document cannot meet the requirements of anti-collapse working conditions, and the production cost is relatively high

[0005] Document 2 is an 80ksi hydrogen sulfide stress-corrosion-resistant alloy steel for oil well pipes and its manufacturing method (patent application number: 201811032877.3). The steel design of the patent in this document is based on the C-Mn-Cr-Mo-V-Ti steel system. Moreover, the content of elements Cr and Mo is relatively high, and the product is mainly designed for the corrosion resistance of hydrogen sulfide. Therefore, the production of the oil well pipe product patented in this document is relatively difficult and the production cost is relatively high, and the product cannot meet the requirements of corrosion resistance. Crash conditions require

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