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Help CenterSteel Pipe & Tube & Petroleum Pipe，H40/J55/K55、N80/L80 C90/T95/P110、Q125/V150
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Steel Pipe & Tube & Petroleum Pipe，H40/J55/K55、N80/L80 C90/T95/P110、Q125/V150NegotiableMOQ: 5 Metric Tons -
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Detailed Description of Oil Country Tubular Goods (OCTG)
1. Product Overview
Oil Country Tubular Goods (OCTG) are special core pipes for oil and gas exploration and development. The product range mainly includes casing, tubing, drill pipes as well as couplings and pup joints. They are widely applied in the whole process of oil and gas well drilling, well completion, oil production, water injection and oil & gas transportation, suitable for conventional wells, deep wells, sour service wells, offshore platforms and other harsh working conditions.
2. Main Classifications and Applications
2.1 Oil Casing
Function: Stabilize well walls to prevent collapse, isolate different formations and oil/gas reservoirs. It bears external formation pressure, internal pressure and axial tension to ensure safe drilling and production.
Application: Run into the wellbore from the ground, divided into surface casing, intermediate casing and production casing. Applicable to unconsolidated formations, high-pressure oil and gas reservoirs and sulfur-containing formations.
Specifications: Outer diameter: 4½"–20" (114.3–508mm); Wall thickness: 6.98–22.23mm; Length: 6–12m.
2.2 Oil Tubing
Function: Serve as the channel for oil and gas to flow from underground formations to the surface, and also used for water injection, gas injection and thermal recovery. It resists internal pressure, tensile force and corrosion.
Application: Run inside casing after well completion, for conventional oil production, heavy oil thermal recovery, high-pressure water injection and transmission of sulfur-containing oil and gas.
Specifications: Outer diameter: 1.050"–5½" (26.7–114.3mm); Wall thickness: 4.83–9.52mm; Length: 6–12.5m.
2.3 Drill Pipe
Function: Transmit torque and drilling pressure to drive drill bits for rock breaking, and circulate drilling fluid to cool bits and carry cuttings.
Application: Key component for drilling operations, suitable for onshore, offshore, deep wells and directional wells.
Specifications: Outer diameter: 2⅜"–6⅝" (60.3–168.3mm); Wall thickness: 7.11–12.7mm; Length: 8–12m.
3. Materials & Steel Grades (Compliant with API 5CT)
3.1 Common Steel Grades and Properties
| Steel Grade | Material Type | Key Characteristics | Applicable Working Conditions |
|---|---|---|---|
| H40 / J55 / K55 | Low Carbon Steel | Low cost, medium strength | Shallow wells, low pressure and non-corrosive environments |
| N80 / L80 | Medium Carbon Steel | High strength and good toughness | Medium-deep wells and conventional oil & gas wells |
| C90 / T95 / P110 | Alloy Steel | Ultra-high strength, excellent collapse resistance and sulfide stress cracking resistance | Deep wells, high-pressure wells and H₂S-containing sour wells |
| Q125 / V150 | High Alloy Steel | Ultra-high strength, resistant to high temperature and high pressure | Ultra-deep wells and offshore high-pressure wells |
| Nickel-based Alloy | Corrosion-resistant Alloy | Resistant to H₂S, CO₂ and chloride ion corrosion | Extreme wells with high sulfur, high chloride and high temperature |
3.2 Manufacturing Process
Seamless Pipe: Formed by hot rolling or cold drawing. Features dense structure and high strength, widely used for high-pressure and corrosive working conditions.
Welded Pipe: Manufactured by high-frequency welding. Cost-effective and high production efficiency, mainly for low-pressure shallow wells.
4. Executive Standards
4.1 International Standards
API 5CT: Core standard for casing and tubing (11th Edition), specifying dimensions, steel grades, mechanical properties and thread types.
API 5B: Code for thread machining, measurement and inspection of casing and tubing.
API 5D: Specification for drill pipes.
API 5L: Specification for line pipes.
4.2 Domestic Standards
GB/T 19830: Petroleum casing and tubing (equivalent to API 5CT).
GB/T 9711: Steel line pipes for oil and gas transmission (equivalent to API 5L).
SY/T 6194: Specification for design and construction of oil and gas well string.
5. Key Technical Parameters
5.1 Mechanical Properties
Yield Strength: 276–1172MPa (increasing with steel grade)
Tensile Strength: ≥ 483MPa, ensuring no fracture under tension
Collapse Resistance: ≥ 20MPa, preventing collapse under external formation pressure
Impact Toughness: ≥ 27J (at room temperature), avoiding brittle fracture at low temperature
5.2 Thread Types
STC (Short Round Thread): Fast connection and low cost, for shallow wells.
LTC (Long Round Thread): Good sealing performance and high tensile strength, for medium-deep wells.
BTC (Buttress Thread): High strength and superior tightness, for deep wells and high-pressure wells.
Premium Thread: Metal-to-metal sealing with excellent corrosion resistance, for sour service wells and offshore wells.
5.3 Anti-corrosion Performance
Conventional Anti-corrosion: External surface coated with coal tar epoxy, internal surface treated with anti-rust oil.
Corrosion-resistant Materials: 13Cr and nickel-based alloys for environments with H₂S, CO₂ and chloride ions.
Coating Protection: Internal anti-corrosion coating such as FBE, applicable for media with high sulfur and high chloride content.
6. Product Advantages
High strength and good toughness, adapting to deep wells, high pressure and complex formations with outstanding collapse, tensile and impact resistance.
Excellent corrosion resistance. Multiple material options resist erosion caused by hydrogen sulfide, carbon dioxide and formation water, extending service life.
Superior sealing performance. Combined with premium thread and metal sealing structure, zero leakage under high pressure to guarantee operation safety.
Complete specifications covering shallow wells to ultra-deep wells, conventional conditions to extreme working scenarios to meet diverse demands.
Fully compliant with API and national standards, globally recognized and applicable to international project bidding.
7. Application Scope
Oil and gas exploitation: Onshore conventional wells, deep wells, shale gas wells and coalbed methane wells.
Special working conditions: Offshore platform wells, high-sulfur sour wells, heavy oil thermal recovery wells and geothermal wells.
Supporting projects: Oil & gas gathering and transmission pipelines, water/gas injection pipelines and matching downhole tools.
8. Packaging & Transportation
Packaging: Both ends equipped with thread protectors. Pipes bundled into sets (5–10 pieces per bundle) and wrapped with waterproof woven bags.
Marking: Clear marks of steel grade, specification, standard, batch number and manufacturer for full traceability.
Transportation: Delivered by road, railway or sea. Avoid collision, moisture and thread damage during transit.
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