Project Description

Carbon Dioxide Corrosion Resistant Oil Casing and Tubing

Detailed Product Description

Carbon dioxide (CO2) corrosion-resistant oil and tubing casing possesses excellent CO2 corrosion resistance, making it suitable for acidic media oil and gas wells containing CO2 or CO2 and Cl⁻ ions. It uses specially designed gas-tight thread connections. The pipe body material is made of economical low-alloy steels containing Cr, Ni, Mo, etc., such as 3Cr, 5Cr, 9Cr, and stainless steels like 13Cr and 15Cr. These materials have high thermodynamic stability and alloy elements that directly inhibit anodic processes (such as Cr, Ni, Mo) and promote cathodic processes and surface activity (like Cu, Si, Al), enabling the formation of a highly stable alloy layer on the material surface, enhancing the tubing’s resistance to CO2 corrosion. The oil and tubing casing connections use self-designed gas-tight thread types suitable for various complex and harsh conditions. Currently, CO2 corrosion-resistant special thread oil and tubing casing have passed rigorous testing by authoritative domestic institutions and are widely used in major domestic oilfields. Specifically, the CB110S-13Cr grade CBS1 tubing has met the requirements of the ISO 13679 CAL-Ⅱ level test for the petroleum and natural gas industries’ casing and tubing thread connection testing procedures. Additionally, CBS3 tubing and casing have passed the stringent CAL-IV level test requirements of ISO 13679.

Commonly Used CO2 Corrosion Resistant Grades

  • CB80-3Cr, L80-9Cr, L80-13Cr, CB90-3Cr, CB95-3Cr, CB95-13Cr, CB110-3Cr, CB110-5Cr, CB110-13Cr, CB110S-13Cr
  • “S” denotes “SUPER,” indicating superior quality.

Self-Designed Gas-Tight Special Thread Connections for CO2 Corrosion Resistant Oil and Tubing Casing

  • CBS1: Gas-tight type I special thread (for tubing and casing)
  • CBS2: Gas-tight type II special thread (for tubing and casing)
  • CBS3: Gas-tight type III special thread (for tubing and casing)
  • CB-FJ: Direct-connect gas-tight special thread (for tubing and casing)
  • CB-EU-HT/CB-BCS-HT: High-torque opposing gas-tight special thread (for tubing and casing)

Standards Complied With (Partial List)

  • API Spec 5CT: Specification for Line Pipe
  • NACE TM0171: Autoclave Corrosion Testing of Metals in High-Temperature Water
  • API Spec 5B: Specification for Processing, Measurement, and Inspection of Threaded Ends of Casing, Tubing, and Line Pipe
  • ISO 13679/GB/T 21267: Petroleum and Natural Gas Industries – Casing and Tubing Thread Connection Testing Procedures

Physical and Chemical Properties

Grade Name Yield Strength (MPa) Tensile Strength (MPa) Elongation (%) Impact Toughness Hardness (HRC) Maximum Application Range
80 CB80-3Cr 552 758 689 As per API 5CT formula As per API 5CT requirement for N80 23 Suitable for environments with lower CO2 corrosion
L80-9Cr, L80-13Cr 552 655 655 As per API 5CT requirement for L80 Used in environments with CO2 corrosion (PCO2 ≥ 0.02 MPa)
90 CB90-3Cr 621 724 689 As per API 5CT requirement for C90 25.4 Suitable for environments with lower CO2 corrosion
95 CB95-3Cr 655 758 724 As per API 5CT requirement for T95 25.4 Suitable for environments with lower CO2 corrosion
CB95-13Cr Used in environments with CO2 corrosion (PCO2 ≥ 0.02 MPa)
110 CB110-3Cr 758 965 862 As per API 5CT requirement for P110 32 Suitable for environments with lower CO2 corrosion
CB110-5Cr Suitable for environments with lower CO2 corrosion
CB110-13Cr Used in environments with CO2 corrosion (PCO2 ≥ 0.02 MPa)
CB110S-13Cr Used in environments with CO2 and minor H2S corrosion (PCO2 ≥ 0.02 MPa)

Joint Performance

Joint Type Internal Pressure and Collapse Resistance Tensile Efficiency Compression Efficiency Applicable Well Conditions
CBS1 Equivalent to pipe body 100% pipe body Tubing: 100% pipe body Casing: 60% pipe body Less harsh well conditions, shallow and medium-depth oil and gas wells
CBS2 100% pipe body Tubing: 100% pipe body Casing: 60% pipe body Harsh well conditions, medium and deep oil and gas wells
CBS3 100% pipe body Tubing: 100% pipe body Casing: 60% pipe body Harsh well conditions, deep wells, ultra-deep wells, horizontal wells
CBS3-HTC 100% pipe body 100% pipe body
CB-FJ 45%~66% pipe body 45%~66% pipe body Repaired wells, tail pipes
CB-EU-HT Equivalent to API EU performance Normal oil wells
CB-BCS-HT Equivalent to API BCS performance Normal oil wells

Product Specifications Range

Outer Diameter: Φ33.4mm ~ Φ219.08mm; Wall Thickness: 3.18mm ~ 22.2mm.