The effects of simulated downhole thermal aging on a proprietary 80 ksi (550 MPa) grade of a seam welded, carbon steel pipe and API 5CT P110, seamless carbon steel pipes that had been cold worked via tubular expansion were studied in the laboratory. The aging increased the transverse compressive yield strength and hardness of the steels as well as causing a significant reduction in their resistance to sulfide stress cracking. Strain aging is responsible for these effects and indicates that it can be used to increase the collapse pressure of these expanded tubular products. Such improvements will both facilitate and broaden the application of downhole tubular expansion as a means of oil and gas well construction. Further work is required to improve the sulfide stress cracking resistance of expanded tubular steels.
Key words: Bauschinger effect, cold work, collapse, downhole, mechanical properties, MR0175, oil and gas, production, steel, strain aging, sulfide stress cracking, SSC, toughness, tubular expansion, well completion.