Anti-collapse oil casing and manufacturing method thereof

Abstract

The invention discloses an anti-collapse oil casing and a manufacturing method thereof. The mixture ratio of chemical compositions thereof by weight percentage is as follows: 0.18-0.34 percent of C; 0.2-1.5 percent of Mn; 0.20-0.50 percent of Si; 0-2.5 percent of Cr; 0-0.8 percent of Mo; 0.02-0.25 percent of V; 0.001-0.06 percent of Al; 0-0.05 percent of Ti; 0.005-0.05 percent of Nb; 0-0.5 percent of Ni; 0-0.5 percent of Cu; 0-0.05 percent of Zr; 0-0.004 percent of B; less than 0.015 percent of P; less than 0.010 percent of S; less than 0.01 percent of Ca; and the balance of Fe and unavoidable impurities. The manufacturing method includes the following steps of: 1) forming round billet through continuous casting; 2) soaking and perforation of the round billet in an annular furnace; 3) helical tube rolling, pinch rolling and sizing; 4) air cooling and saw cutting after tube rolling; 5) quenching and tempering, and water quenching; 6) high temperature tempering, hot sizing and thermal straightening; and 7) flaw detection. With the mixture ratio and the method, the invention can obtain the anti-collapse casing with superhigh anti-collapse capability and excellent performance through texture and microstructure design and control.

Description

technical field [0001] The invention relates to an oil casing for oil and natural gas wells, in particular to a high-quality and ultra-high collapse-resistant oil casing and a manufacturing method thereof. Background technique [0002] It is generally believed that the casing whose critical collapse stress exceeds the specified value of API Bul 5C2 and reaches a certain minimum value is called ultra-high collapse resistant casing. Table 1 shows the minimum collapse strength of ultra-high collapse-resistant tubing with different strengths and specifications. [0003] Table 1 Minimum collapse strength to be achieved for ultra-high extrusion sleeves [0004] [0005] This kind of casing is an indispensable special pipe for oil and gas well completion operations such as deep wells and ultra-deep wells. Seal various complex formations to ensure the effect of drilling. With the increase of well depth and well pressure of oil wells in western my country, the difficulty of exp...

AI Technical Summary

Problems solved by technology

The steel used in this patent is the traditional CrMo steel with Nb added. Due to the simple chemical composition, the microstructure, geometric size and residual stress of the steel pipe are not strictly controlled. high demand

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