Welded Steel Pipe
Technical Specifications – Welded Steel Pipe Parameters
The following tables summarize key technical parameters for SJ Petro welded steel pipe products.
Casing Specifications (API Spec 5CT)
| Size OD (inches) | Weight Range (lb/ft) | Grade | Connection Type | Application |
|---|---|---|---|---|
| 4‑½″ to 9‑⅝″ | 9.5–53.5 | H40, J55, K55, N80, L80, C95, P110 | BTC, LTC, STC, Premium | Conductor, surface, intermediate, production casing |
| 10‑¾″ to 13‑⅜″ | 32.75–68.05 | J55, K55, N80, P110 | BTC, LTC | Intermediate and production casing |
| 16″ to 20″ | Custom | H40, J55, K55 | BTC | Surface casing |
Tubing Specifications (API Spec 5CT)
| Size OD (inches) | Weight Range (lb/ft) | Grade | Connection Type | Application |
|---|---|---|---|---|
| 1.9″ to 2-⅞″ | 2.9–6.5 | J55, N80, L80, P110 | EUE, NUE, Premium | Production tubing, well completion |
| 3-½″ to 4-½″ | 7.7–15.5 | J55, N80, L80, C95, P110 | EUE, NUE, Premium | Large‑bore production, gas lift |
Drill Pipe Specifications (API Spec 5DP)
| Size OD (inches) | Nominal Weight (lb/ft) | Grade | Tool Joint OD (inches) | Upset Type |
|---|---|---|---|---|
| 2-⅜″ | 6.65 | E75, X95, G105, S135 | 3-⅛″ | IU / EU |
| 2-⅞″ | 10.40 | E75, X95, G105, S135 | 3-⅞″ | IU / EU |
| 3-½″ | 13.30 / 15.50 | E75, X95, G105, S135 | 4-¾″ | IU / EU |
| 4″ | 14.00 / 15.70 | E75, X95, G105, S135 | 5-¼″ | IU / EU |
| 4-½″ | 16.60 / 20.00 | E75, X95, G105, S135 | 6-⅜″ | IU / EU |
| 5″ | 19.50 / 25.60 | E75, X95, G105, S135 | 6-⅝″ | IU / EU |
| 5-½″ | 21.90 / 24.70 | E75, X95, G105, S135 | 7″ | IU / EU |
| 6-⅝″ | 25.20 / 27.70 | E75, X95, G105, S135 | 7-¾″ | IU / EU |
Innovation & Technical Advantages – API Compliance at Every Stage
API 5CT & 5DP Full Certification
Every welded steel pipe shipment includes complete API documentation: material test reports (MTRs) from certified mills, dimensional inspection records, NDT (ultrasonic and electromagnetic) inspection reports, hydrostatic test certificates and a certificate of conformance to API 5CT or API 5DP.
Third‑party inspection by BV, SGS, DNV or ABS is welcome at any stage of manufacturing.
Dimensional Tolerances & Quality Control
Our welded steel pipes meet stringent API dimensional tolerances:
-
OD tolerance – ±0.75% to ±1.0% depending on size and product specification level
-
Wall thickness tolerance – -12.5% to +15% per API 5CT/5DP requirements
-
Length tolerance – ±1.5 inches for range 2 and range 3 lengths
-
Straightness – Maximum 0.2% of pipe length
All pipe undergoes 100% NDT (ultrasonic or electromagnetic inspection) for longitudinal flaws. Hydrostatic testing is performed on every length.
Corrosion-Resistant & Sour Service Options
For wells with hydrogen sulfide (H₂S) or carbon dioxide (CO₂), standard carbon steel pipes are not sufficient. SJ Petro supplies welded steel pipe in corrosion‑resistant alloys and sour service grades including:
-
L80-13Cr casing – For CO₂ corrosion resistance
-
C95 sour service casing – Hardness‑controlled for H₂S resistance (≤ 25.4 HRC)
-
Stainless steel OCTG pipes – For CO₂ injection and highly corrosive environments
-
Nickel alloy clad pipe – For extreme sour service applications
All sour service materials meet NACE MR0175 / ISO 15156 hardness and composition requirements.
Premium Threading & Connections
SJ Petro welded steel pipe is available with a full range of API and premium thread connections:
-
BTC (Buttress Thread Casing) – For high‑torque, high‑tensile casing applications
-
LTC (Long Thread Casing) – Standard API connection for most casing strings
-
STC (Short Thread Casing) – For lower pressure, shallow applications
-
EUE (External Upset End) and NUE (Non‑Upset End) – For tubing connections
-
Premium connections – VAM, Hydril, Tenaris equivalent on request
Connections are inspected to API 7‑2 gauge specifications for perfect interchangeability with industry‑standard tooling.
Application Fields – Where Our Welded Steel Pipe Products Operate
Onshore Oil & Gas Wells (Conventional and Unconventional)
From vertical exploration wells to multi‑stage fractured horizontal wells, our casing, tubing and drill pipe strings provide the structural backbone. SJ Petro OCTG products are deployed across major Chinese oil basins and exported to onshore fields worldwide.
High‑Pressure High‑Temperature (HP/HT) Wells
Deep and ultra‑deep wells demand pipe with higher strength and thicker walls. Our P110 and Q125 grade casing and tubing, along with S135 grade drill pipe, are designed for extreme loads at depths exceeding 7,000 meters. SOFE has formed competitive ultra‑deep well products including bits, drilling rigs, coiled tubing units and electric fracturing equipment packages.
Sour Gas Wells (High H₂S Environment)
Sour gas fields present one of the most challenging tubular applications. SJ Petro supplies sour service casing and tubing (L80, C95) with controlled hardness and NACE MR0175 compliance for H₂S resistance. SOFE is actively engaged in developing and manufacturing proud pillar equipment for sour gas fields.
Offshore Drilling & Subsea Completions
Offshore platforms and subsea wells require corrosion‑resistant pipe, premium thread connections and rigorous third‑party inspection. SJ Petro casing, tubing and drill pipe are certified for offshore applications and have been supplied to international offshore operators.
International Oilfield Export – 30+ Countries
SJ Petro and Sinopec Oilfield Equipment Corporation have a strong international presence. SOFE's steel pipes are highly favored in the international market, with successful expansion through enhanced product quality, streamlined manufacturing and bolstered after‑sales support. Notably, SOFE has supplied high‑quality steel pipes to water pipeline construction projects in Saudi Arabia. Our OCTG products are exported across the Middle East, Central Asia, Russia and other key oil‑producing regions.
Why Choose SJ Petro for Welded Steel Pipe?
Backed by Sinopec – One of China's Top 500 Manufacturers
SJ PETROLEUM MACHINERY Co., Ltd. is a wholly‑owned subsidiary of Sinopec Oilfield Equipment Corporation (SOFE, Stock Code: 000852.SZ), a China Critical Technological Equipment Nationalization Base and National Hi‑tech Enterprise. We are ranked No.2 among China Top 10 Petroleum Drilling and Production Equipment Manufacturers. As an integrated manufacturer of petroleum machinery, we combine steel pipe production with rig manufacturing, downhole tools and wellhead equipment under one roof.
Full API Certification – 5CT, 5DP, Monogram License
All SJ Petro welded steel pipe products are designed, manufactured and tested to API Spec 5CT (casing and tubing) and API Spec 5DP (drill pipe). We maintain an active API monogram license (Certificate Number: 7-1-0120) for our certified products.
Integrated Manufacturing – One Supplier, One Quality Standard
SOFE's 16 production lines cover the full spectrum of oilfield equipment: drill bits & tools, drilling and workover rigs, cementing and fracturing units, wellhead equipment and steel pipe, all under one quality management system. Whether you need API 5DP drill pipe, API 5CT casing, premium tubing or complete rig packages, SJ Petro offers seamless integration.
Global Export Track Record – Proven in International Markets
SJ Petro and SOFE have a long history of international exports:
-
Steel pipe supplied to water pipeline construction projects in Saudi Arabia
-
Drilling and workover rigs exported to Russia, North and South America, Middle East and Southeast Asia
-
Full API documentation packages and GOST certification for Russian/Eurasian markets available
End‑to‑End Service – From Mill to Wellsite
Unlike steel‑only suppliers, SJ Petro provides:
-
Complete technical support for pipe selection based on well conditions(pressure, depth, corrosion)
-
Third‑party inspection coordination – BV, SGS, DNV, ABS witness testing available
-
Export documentation – Full API certification packages, MTRs, NDT reports, hydrostatic test certificates
-
On‑site technical training for thread inspection, pipe handling and running procedures
Frequently Asked Questions (FAQ)
Q1: What is the difference between welded and seamless steel pipe for oil wells?
A: Seamless pipe is manufactured by piercing a solid steel billet, then elongating and rolling it to size. It has no weld seam, providing uniform wall thickness and higher resistance to collapse and burst pressures. Seamless pipe is the standard for high‑pressure and deep‑well drilling applications. Welded pipe is formed from flat steel coil and welded along the longitudinal seam. Modern high‑frequency welded (HFW) pipe offers excellent quality and is often used for less demanding casing strings. For many oilfield applications within appropriate pressure and depth ratings, API‑certified welded casing and tubing provide reliable, cost‑effective solutions.
Q2: What API standards apply to SJ Petro welded steel pipe products?
A: Our products are manufactured to API Spec 5CT for casing and tubing, and API Spec 5DP for drill pipe. API 5CT covers seamless and welded casing and tubing in grades H40 through Q125. API 5DP covers drill pipe with upset pipe body ends and welded‑on tool joints in PSL‑1, PSL‑2 and PSL‑3. We maintain an active API monogram license and are subject to annual API audits.
Q3: What steel grades do you offer for casing and tubing?
A: SJ Petro offers the full range of API 5CT steel grades: H40, J55, K55, N80, L80, C95, P110 and Q125. For sour service applications requiring H₂S resistance, we supply L80-13Cr (13% chrome for CO₂ corrosion) and C95 (hardness‑controlled). For high‑pressure deep wells, P110 and Q125 grades provide the necessary strength. We can also supply stainless steel OCTG pipes for CO₂ injection applications.
Q4: What is the size range for your drill pipe products?
A: SJ Petro drill pipe is available in API standard sizes from 2-⅜″ to 6-⅝″ OD, with nominal weights from 6.65 lb/ft to 27.70 lb/ft. Grades include E75, X95, G105 and S135. Tool joints are API‑specified sizes and can be hardbanded for wear resistance on request. PSL‑1, PSL‑2 and PSL‑3 product specification levels are available.
Q5: Can you supply welded steel pipe for sour gas wells with H₂S?
A: Yes. SJ Petro supplies L80, C95 and higher grades with hardness controlled to ≤ 25.4 HRC per NACE MR0175 / ISO 15156 for H₂S resistance. All sour service material undergoes stringent chemical analysis, hardness testing and NDT inspection. Our 6000 HP pump test center and dedicated quality inspection laboratories ensure that sour service products meet the most rigorous international standards.
Q6: What connections are available for your casing and tubing?
A: We supply all API connections: BTC (Buttress Thread Casing), LTC (Long Thread Casing), STC (Short Thread Casing). For tubing, we supply EUE (External Upset End) and NUE (Non‑Upset End) connections. Premium connections (equivalent to VAM, Hydril, Tenaris) are available on request. All threads are inspected to API 7‑2 gauge specifications to ensure perfect interchangeability.
Q7: What is the typical lead time for welded steel pipe orders?
A: Lead time depends on size, grade, quantity and specification level:
-
Standard API casing / tubing (stock sizes, J55/N80): 4–6 weeks
-
P110 and Q125 casing / tubing: 6–8 weeks
-
API 5DP drill pipe (any grade): 6–8 weeks
-
Sour service / premium connection orders: 8–10 weeks
-
Large OCTG procurement projects (5,000+ tons): 10–12 weeks
Expedite options may be available for emergency shipments—contact our sales team for current availability.
Q8: What is included in your API certification package?
A: Each shipment includes: Material test reports (mill certificates) showing chemical composition and mechanical properties; dimensional inspection records; NDT (ultrasonic / electromagnetic) inspection reports; hydrostatic test certificates; and a certificate of conformance to API 5CT or API 5DP. Third‑party witnessed testing (BV, SGS, DNV, ABS) is available at additional cost.
Q9: Do you provide thread inspection training for field crews?
A: Yes. SJ Petro offers on‑site training for drilling and workover crews on proper thread inspection, pipe handling, dope application and connection make‑up procedures. Training includes both classroom instruction and hands‑on practice with gauges and connection tools.
Q10: How do I request a quote for SJ Petro welded steel pipe products?
A: Please provide the following information to our export sales team:
-
Product type (casing, tubing or drill pipe)
-
Size OD (inches) and grade
-
Quantity(tons or joint count)
-
Connection type(BTC, LTC, STC, EUE, NUE or premium)
-
End finish (plain end, beveled, threaded and coupled)
-
Range length (R1, R2 or R3)
-
Additional specifications (sour service, low temperature, premium connection)
-
Third‑party inspection requirements (if any)
We will respond within 3–5 business days with a technical proposal and firm price quotation.
