In recent news, significant advancements have been made in the production of raw materials for oil casing pipes, a critical component in the oil and gas industry. These developments not only enhance the performance of the pipes but also expand the range of applications they can serve.
Oil casing pipes, often referred to as “the lifeline of maintaining oil well operations,” are steel tubes used to stabilize the walls of oil and gas wells during drilling and extraction. These pipes are inserted into the wellbore and cemented in place, serving to isolate rock formations and prevent wellbore collapse while ensuring the circulation of drilling mud, facilitating exploration and extraction. They are disposable materials and cannot be reused, accounting for over 70% of all oil well pipe consumption.
One notable breakthrough comes from Baotou Steel (Group) Co., Ltd., which has successfully trial-produced Super 13Cr rare earth corrosion-resistant oil casing pipes. This high-performance martensitic stainless steel corrosion-resistant tubing incorporates nickel, molybdenum, and copper alloy elements during smelting, resulting in higher strength, better low-temperature toughness, and superior resistance to carbon dioxide and hydrogen sulfide corrosion. These properties make it ideal for ultra-deep, ultra-high-pressure, and ultra-high-temperature “three ultra” oil and gas resource development applications.
The unique rare earth resources of Baotou Steel have enabled the company to adopt rare earth microalloying treatment, improving the microstructure and inclusion morphology of the material’s rare earth elements to form a dense oxide film, significantly enhancing the corrosion resistance of the Super 13Cr oil casing pipes. Additionally, the company applies hot continuous rolling, heat treatment, flaw detection, and other full-process control technologies during production to ensure product quality and dimensional accuracy.
Another significant development is in the production of TP110T steel grade oil casing pipes using 27MnCrV steel, a new steel type. Compared to conventional steel types like 29CrMo44 and 26CrMo4 used in producing TP110T steel grade oil casing pipes, 27MnCrV contains less molybdenum, significantly reducing production costs. However, it poses challenges such as high-temperature embrittlement and low and unstable impact toughness when produced using normal austenitizing quenching processes.
To address these issues, two methods are employed: rapid cooling after tempering to avoid high-temperature brittleness and obtain toughness, and intercritical quenching to effectively improve harmful elements and impurities by incomplete austenitizing, enhancing toughness. The intercritical quenching process involves heating the steel between 740-810°C, with a specific heating temperature of 780°C for 15 minutes, followed by tempering at 630°C for 50 minutes. This process retains partially undissolved ferrite, maintaining high strength while improving toughness. The low-temperature quenching also reduces quenching stress and deformation, ensuring smooth heat treatment operations and providing high-quality raw materials for subsequent threading and other processes.
Quality assurance data from the processing plant indicates that the heat-treated steel pipes have a yield strength of 820-860 MPa, tensile strength of 910-940 MPa, impact toughness of 65-85 J, and 100% pass rate in destruction resistance tests. These figures demonstrate that 27MnCrV steel pipes are high-quality, high-grade oil casing pipes, and the intercritical quenching process is effective in avoiding high-temperature brittleness in steel production.
These advancements in oil casing pipe material production not only improve the quality and performance of the pipes but also expand their application range, contributing to more efficient and sustainable oil and gas exploration and extraction. As the demand for oil and gas resources continues to grow, these innovations will play a crucial role in ensuring the stability and reliability of the global energy supply.