125 ksi high-strength and high-toughness petroleum casing pipe for exploring thickened oil through SAGD method and manufacturing method thereof

Abstract

The invention provides a 125 ksi high-strength and high-toughness petroleum casing pipe for exploring thickened oil through the SAGD method and a manufacturing method thereof. The casing pipe comprises, by weight, 0.23-0.28% of C, 0.17-0.30% of Si, 0.56-0.75% of Mn, smaller than or equal to 0.015% of P, smaller than or equal to 0.007% of S, smaller than or equal to 0.20% of Ni, 1.0-1.20% of Cr, 0.35-0.55% of Mo, smaller than or equal to 0.15% of Cu, smaller than or equal to 0.01-0.04% of Al and the balance Fe. The manufacturing method includes the steps of selecting raw steel-making materials; adjusting steel compositions through external refining, vacuum degassing and argon stirring; lowering the out-of-roundness of the outer diameter and the unevenness of the wall thickness of a steel pipe by carrying out high-precision rolling through a PQF unit; and carrying out heat treatment to obtain high-strength and high-toughness matching and lowering the residual stress of the steel pipe by increasing the thermal straightening temperature and through the stress relief annealing technology. The casing pipe and the manufacturing method thereof have the beneficial effects that the heat stability is good, the yield strength is not lower than 800 MPa at 350 DEG C, the external extrusion deformation resistance is high, the actual anti-collapse property is higher than the API calculation value by more than 56%, and the requirements of exploring the thickened oil through the SAGD method are met.

Description

technical field [0001] The invention relates to an oil casing and a production method thereof, in particular to a 125ksi high-strength and tough oil casing for heavy oil exploitation by the SAGD method and a manufacturing method thereof. Background technique [0002] Heavy oil refers to crude oil with a relative density greater than 0.92 at a temperature of 20°C and a viscosity greater than 50mPa·S under oil reservoir conditions. Due to its high viscosity and poor fluidity, heavy oil cannot be recovered by conventional methods. Steam injection recovery technologies are generally used, mainly steam huff and puff and steam flooding recovery technologies. However, steam huff and puff and steam flooding recovery methods can only heat steam injection wells The oil reservoirs in a small area near the wellbore have low recovery, and the viscosity of crude oil is required to be less than 50,000mPa·S. For crude oil with a viscosity higher than 100,000mPa·S, new extraction technologie...

AI Technical Summary

Problems solved by technology

With the continuous production of heavy oil, there is a deficit in the underground, the surface sinks, and the production string is locally subjected to large extrusion stress. The existing API steel grade casings are not up to use in terms of high temperature performance and anti-collapse performance. Require

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