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Help CenterSteel Pipe & Tube & Oil Country Tubular Goods，J55、K55、N80-1/N80-Q、L80-1、P110、C90、T95、L80-13Cr、G105、S135
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1. Product Overview
Petroleum pipes, collectively called OCTG (Oil Country Tubular Goods), are core special seamless steel pipes for oil & gas exploration, drilling, well completion, oil production and long-distance gathering transmission pipelines. They are designed to withstand extreme harsh downhole working conditions including high temperature, high pressure, H₂S/CO₂ acid medium and formation extrusion stress. Main four categories: Casing, Tubing, Drill Pipe and Line Pipe. All products comply with API American Petroleum Institute specifications, widely applied in domestic oilfields, overseas oil projects and refinery facilities.
2. Applicable Standards
Core API International Standards
API Spec 5CT: Oil & gas well casing and tubing (downhole completion pipes)
API Spec 5L: Line pipe for long-distance oil & gas transmission
API Spec 7/7-1: Drill pipe & drill collar
ISO 3183, DNV OS-F101 (certificate for offshore pipeline export)
Domestic Chinese Standards
SY/T 6194, GB/T 9711, GB/T 28708, GB/T 19830
Third-Party Certifications
API monogram certification, SGS, CE, UT eddy current test report, Mill Test Certificate (MTC)
3. Main Material Grades
3.1 Casing & Tubing Grades (API 5CT) General Service
J55, K55, N80-1/N80-Q, L80-1, P110 (for deep wells)
3.2 Sulfide Resistant Grades for Sour Oil & Gas Wells
C90, T95, L80-13Cr, 9Cr, 3Cr series (anti-H₂S hydrogen sulfide corrosion)
3.3 Line Pipe Grades (API 5L) for Transmission
Gr.B, X42, X52, X60, X65, X70, X80 (PSL1 & PSL2 two quality levels)
3.4 Drill Pipe Special Grades
G105, S135, U165 high strength alloy drill pipe
4. Four Main Product Types & Functions
4.1 Casing
Permanently run into wellbore to support wall, isolate formation pressure, prevent collapse and interlayer fluid channeling; classified as surface casing, intermediate casing and production casing.
Outer Diameter: 114.3mm ~ 508mm (4"~20")
Thread Types: STC Short Round Thread, LTC Long Round Thread, BTC Buttress Thread, premium airtight connections like VAM
4.2 Tubing
Suspended inside casing to transport oil & gas from reservoir to surface, also for water injection in injection wells; divided into NU Non-Upset, EU External Upset, IJ Integral Joint.
Outer Diameter: 60.3mm ~ 114.3mm (2"~4.5")
End Finish: CNC threaded with matching couplings, phosphated thread for lubrication & tight sealing
4.3 Drill Pipe
Transmission component for drilling operations, transfer torque & drilling fluid from surface rig to drill bit; friction-welded upset ends with high torsion & tensile resistance.
4.4 Line Pipe
Onshore/offshore trunk pipe for crude oil, natural gas and mixed medium transportation; applied in land gathering networks and cross-river/subsea pipelines, available with 3PE/FBE anti-corrosion coating.
5. Complete Production Process
Raw billet spectral re-inspection → High temperature heating 1100-1250℃ → Hot rolling piercing → Sizing & straightening → Controlled heat treatment (Normalizing / Tempering / Quench & Temper) → Pipe end upsetting (for tubing & casing) → Precision CNC threading → Thread phosphating & passivation → NDT UT/MT inspection → Hydrostatic pressure test per single pipe → Length weighing & marking → Anti-rust oil / anti-corrosion coating → Plastic end caps for thread protection → Bundling & fumigated pallet warehousing
6. Core Technical Parameters
6.1 Size Range
Outer Diameter (OD): 26.7mm ~ 830mm
Wall Thickness (WT): 3.5mm ~ 120mm, thin wall, heavy wall & extra heavy wall customizable
Standard Fixed Length: 9.6m, 10.6m, 12m (12m is mainstream for export)
End Treatment: Plain end, beveled end, CNC threaded end, external upset, integral joint
6.2 Mechanical & Pressure Performance
Collapse Resistance: Resist extrusion force from formation rock to avoid pipe deformation
Tensile Strength: Withstand self-weight tension during running & pulling operations, P110 for ultra-deep wells
Internal Pressure Tightness: Airtight thread joint test, zero leakage under high pressure oil & gas service
Temperature Resistance: Regular grades ≤120℃; Cr-Mo anti-sulfide alloy pipe up to 180℃ for high temperature wells
6.3 Anti-Corrosion Treatment
Short-term protection: Thread phosphating, whole pipe anti-rust oil, black varnish
Long-distance pipeline anti-corrosion: Single layer FBE epoxy powder, 3-layer PE (3PE), epoxy coal tar pitch
Corrosion resistant material: 13Cr stainless tubing for high CO₂ oil & gas wells
7. Core Product Advantages
API standard original process, high thread precision & stable sealingPrecision CNC threading with uniform fit clearance, no leakage under high pressure & alternating load, suitable for deep wells and high-pressure gas wells.
High strength anti-deformation, fit complex geological conditionsUniform metallographic structure after controlled rolling heat treatment, qualified collapse resistance, tensile strength and internal pressure resistance, covering shallow to ultra-deep wells.
Sulfide & corrosion resistant, extend downhole service lifeL80, C90, 13Cr series resist corrosion from hydrogen sulfide, carbon dioxide and chloride ion, solve perforation problems of sour oilfields.
Full size spot inventory, customized premium special connections availableAdequate stock of regular grades, customizable premium airtight threads such as VAM, NK3SB for strict offshore projects.
Line pipe matched with complete anti-corrosion coating system3PE/FBE coated line pipes serve long-term underground & subsea transportation, resist electrochemical corrosion from soil & seawater.
Full API factory inspection, complete documentationMTC material certificate, API certification, NDT report and hydrostatic test record provided for each batch, smooth customs clearance.
8. Main Application Fields
Onshore & offshore oil & gas drilling, completion & production (main scenario for casing, tubing & drill pipe)
Oilfield gathering pipelines, long-distance crude oil & natural gas trunk lines (API 5L line pipe)
Shale oil, coalbed methane, geothermal high temperature deep well extraction pipes
High-pressure process pipelines in refineries, high-pressure station piping for oil & gas transmission
Special anti-corrosion OCTG for sour & sulfur-containing gas fields
Urban gas main pipelines, cross-river & subsea pipeline engineering
9. Packaging, Shipment & Lead Time
Packaging Methods
Tubing & small diameter casing: Bundled with steel strips, plastic thread caps on both ends, wrapped with waterproof anti-rust film
Large diameter casing & line pipe: Single pipe wrapped with waterproof woven cloth, dust-proof seal for pipe ends
Export dedicated: IPPC fumigated solid wooden pallets, fit for 40HC high cube container sea transportation
2. Delivery Warehouse: Spot goods shipped directly from Tianjin Port
3. Lead Time: 5-7 days for regular stock goods; 12-18 days for customized orders of special grades, premium threads and anti-corrosion coatings
4. Payment Term: 30% TT advance deposit, balance paid before shipment, L/C letter of credit is not accepted.
10. Full Factory Inspection Items
Spectral chemical composition analysis of raw materials
Precision measurement of outer diameter, wall thickness, length and thread dimension
Full-length ultrasonic UT inspection & magnetic particle MT surface flaw detection
Hydrostatic pressure tightness test for every single pipe
Tensile, impact and hardness mechanical property test
Thread standoff distance & airtight sealing test
Anti-corrosion coating thickness & adhesion test (for line pipe)
API Mill Test Certificate, factory certificate and third-party SGS test report provided
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