L80 Oil Casing

L80 Oil Casing is a widely used medium strength casing in API standards, with "L80" indicating a minimum yield strength of 80ksi (approximately 552MPa). With balanced mechanical properties and corrosion resistance, it has become the mainstream choice for conventional oil and gas wells and slightly corrosive environments, with a market share of over 25%.

Performance characteristics

The yield strength of L80 casing is between 552-758MPa, the tensile strength is not less than 655MPa, the elongation rate is ≥ 18%, the impact energy is ≥ 30J, it has good toughness and deformation resistance, and can withstand formation pressure and wellbore fluid pressure at depths of 1500-3000 meters. The upper limit of temperature resistance reaches 140 ℃, and the performance is stable within this temperature range, which can meet the needs of most conventional oil and gas wells.

Material classification

Ordinary type: made of 13Cr low-alloy steel, suitable for neutral or weakly corrosive conventional oil and gas well environments, and can cope with general formation conditions and medium influences.

Sulfur resistant type (L80-13Cr): With a chromium content of 13%, it has passed HIC (hydrogen induced cracking) and SSC (sulfide stress corrosion) tests and can withstand environments with H ₂ S concentration ≤ 500ppm. It is suitable for oil and gas wells with slight hydrogen sulfide corrosion.

Production process

The tube blank is made into a blank tube by hot rolling perforation, and then cold rolling finishing is carried out to ensure dimensional accuracy, with strict control of outer diameter tolerance. Next, quenching and tempering heat treatment (820 ℃ quenching+550 ℃ tempering) is carried out to improve the mechanical properties of the pipe. The thread machining accuracy meets the API 5B standard, and the sulfur resistant type requires additional passivation treatment to enhance its corrosion resistance.

Application scenarios

Widely used in conventional oil and gas wells at depths of 1500-3000 meters, it is a common choice for water injection and oil production casing in onshore oil fields. In formations with slight corrosion (low concentration of CO ₂), it can also play a good role and has a better cost-effectiveness than C90 casing.