High temperature resistant oil well pipe for thermal recovery well and its manufacturing method

Abstract

The invention discloses a high-temperature-resistant oil well pipe used for a thermal recovery well and a manufacturing method for the oil well pipe. Chemical composition in steel comprises, by weight, 0.36%-0.60% of C, 0.46%-0.70% of Si, 1.60%-1.80% of Mn, less than or equal to 0.025% of P, less than or equal to 0.015% of S, 1.6%-1.8% of Cr, 0.01%-0.03% of Nb, 0.01%-0.03% of Ti, and the balance Fe and unavoidable impurities. The heating temperature for a round billet is 1240-1300 DEG C, the pipe manufacturing temperature is 1050-1150 DEG C, isothermal quenching heat treatment is conducted on a molded steel pipe, the molded steel pipe is subjected to heat preservation for 4-15 s at the temperature of 980-1000 DEG C and quickly cooled with the cooling speed being greater than 130 DEG C per second, the temperature is maintained for 20-40 min after the molded steel pipe is cooled to the temperature of 200-300 DEG C, and then the steel pipe is cooled to the room temperature. The manufactured high-temperature-resistant oil well pipe used for the thermal recovery well has excellent high temperature creep resistant and intensity attenuation resistant properties.

Description

technical field [0001] The invention belongs to the technical field of low-alloy steel manufacturing, and mainly relates to an oil well pipe for thermal recovery wells with excellent performance used in a temperature environment of 400°C or higher and a manufacturing method thereof. Background technique [0002] The world's proven reserves of heavy oil resources are more than 300 billion tons, and the resources available for exploitation are about 170 billion tons. In the past, the exploitation of heavy oil was mainly concentrated in the American continent, and the exploitation of heavy oil in Asia has also been developed in the past 20 years. In the early 1980s, my country's heavy oil resources began to be industrially developed. By 2002, the output reached 13 million tons, accounting for 8% of the national crude oil output. Thermal recovery of heavy oil puts forward special requirements on the performance of oil well pipes, and it is necessary to develop high-performance ...

AI Technical Summary

Problems solved by technology

The oil casing manufactured according to this scheme has a certain heat resistance, which can meet the use of the early thermal recovery steam wells with a temperature of 300°C. The disadvantage is that the normal temperature yield strength of the designed product can only be guaranteed to be no less than 690MPa , that is, 100ksi, since the strength of this product will be significantly attenuated when it is operated at high temperature, the yield strength under actual use conditions can only be no less than 80ksi, which can only meet the conditions of early shallow wells and operating temperatures that are not too high It can not meet the latest application requirements of higher temperature environment and lower limit of yield strength

The oil casing manufactured according to this scheme has a certain heat resistance and can be used in thermal recovery wells with a temperature of 350°C in the early stage. The disadvantage is that the yield strength of the designed product can only reach less than It is lower than 600MPa, that is to say, it can only be used as an 80ksi steel grade oil well pipe in a thermal recovery well at a high temperature environment of 400°C. The ability of collapsing and breaking is also greatly reduced. Therefore, it cannot meet the increasing requirements of oil fields for heat resistance and strength of thermal recovery tubing.

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