API 5CT K55 Oil Casing Seamless Steel Tubing
API 5CT K55 seamless steel pipe is a premium carbon steel casing and tubing product manufactured in strict accordance with the API Spec 5CT international petroleum industry standard. As a mainstream medium-strength steel grade for oil and gas well engineering, K55 seamless pipe features stable mechanical performance, excellent pressure resistance, superior structural toughness and reliable anti-deformation capability. Without welding seams, the pipe eliminates structural weak points of welded pipes, ensuring high safety and durability in harsh underground working environments. It is widely applicable for conventional oil and gas well casing, tubing, and wellbore support projects, serving as a core basic component for onshore and shallow offshore petroleum exploration and development.
Mechanical Index | Standard Value (MPa) | Standard Value (PSI/KSI) |
|---|---|---|
Yield Strength | 379 - 552 MPa | 55 - 80 KSI (50,000 PSI Min) |
Tensile Strength (Min) | 655 MPa | 95 KSI (55,000 PSI Min) |
Elongation (Min) | ≥ 18% | ≥ 18% |
Element | C | Si | Mn | P | S | Cr/Ni/Cu |
|---|---|---|---|---|---|---|
Content | 0.40 | 0.35 | 1.50 | 0.030 | 0.030 | 0.20 |
Size Specification Range
Outer Diameter (OD): 2 7/8" - 9 5/8" (Customizable conventional oilfield standard sizes)
Wall Thickness: 1.0mm - 30mm (0.244 inch - 0.875 inch)
Standard Length: - R1: 4.88m - 7.62m - R2: 7.62m - 10.36m - R3: 10.36m - 14.63m (Most commonly used for K55 casing)
End Processing: Plain end, Threaded end (STC/LTC/BTC/XS/Premium thread), Upset end (EU/NU)
Application Fields
API 5CT K55 seamless steel pipe is specially designed for petroleum and natural gas industry well engineering, focusing on medium and low-pressure conventional well scenarios, with wide industrial adaptability:
·Onshore Conventional Oil & Gas Wells: Casing and tubing for shallow and medium-depth oil/gas wells, wellbore fixing, isolation of oil, gas and water layers
·Shallow Offshore Well Projects: Low-pressure shallow sea oil and gas exploration and development wellbore support
·Water Injection & Gas Injection Wells: Medium-pressure water and gas injection pipeline for oilfield secondary development
·Geothermal Well & Coalbed Methane Projects: Well casing for conventional geothermal energy and coalbed methane extraction
·Oilfield Auxiliary Pipeline: Oil and gas transmission short pipeline, wellhead connecting pipeline and supporting facilities
FAQ (Frequently Asked Questions)
Q1: What is the difference between K55 and J55 steel grade?
Both K55 and J55 are medium-strength API 5CT carbon steel grades with similar tensile strength. The core difference lies in yield strength and application scenarios. K55 has higher yield strength and better structural stability under long-term formation pressure, more suitable for medium-depth wells with slightly higher pressure and stricter deformation resistance requirements; J55 is more cost-effective for shallow low-pressure conventional wells.
Q2: Is K55 seamless pipe suitable for high-pressure deep well operation?
K55 is a medium-strength steel grade, ideal for shallow and medium-depth conventional oil/gas wells with conventional pressure working conditions. For ultra-deep wells, high-pressure and high-temperature wells, or wells with severe formation stress, it is recommended to upgrade to higher-grade steel such as N80, L80 or P110 to ensure long-term operational safety.
Q3: What certifications and test reports can you provide?
We provide full standard qualification documents, including API 5CT factory certification, EN 10204 3.1/3.2 material test certificate, chemical composition & mechanical property test report, non-destructive testing report, and support SGS, BV and other third-party authoritative inspection and certification.
Q4: What is your MOQ and delivery time?
The minimum order quantity is 20 tons. For conventional standard sizes in stock, delivery can be completed within 7-10 working days; for customized sizes and special processed products, the delivery cycle is 15-25 working days according to the processing difficulty.
Q5: How to ensure the product quality of API 5CT K55 pipe?
All products are produced in full compliance with API 5CT standards, adopting one-piece hot rolling seamless forming technology. Each batch of products undergoes strict hydraulic pressure test, ultrasonic flaw detection, mechanical performance test and chemical composition analysis. We support full-process quality tracking and after-sales quality guarantee.
Q6: What thread types are available for K55 casing pipe?
We support all mainstream oilfield standard threads, including STC (Short Thread), LTC (Long Thread), BTC (Buttress Thread), XC thread and various premium special threads, and can provide matching couplings, thread protectors and supporting accessories.
