API 5CT N80 and L80 Seamless OCTG Casing Delivered to Halliburton for Deepwater Drilling Campaign Offshore Angola — Air Freight Expedited

DF Steel Pipe has successfully completed an urgent delivery of API 5CT N80-Q and L80-1 (13Cr) seamless OCTG casing pipes to Halliburton for a deepwater drilling campaign in Block 17, offshore Angola. The order included both 9-5/8" OD (53.5 lb/ft) surface casing and 13-3/8" OD (68 lb/ft) conductor casing with BTC (Buttress Thread Casing) connections per API 5B. Due to the critical rig mobilization schedule, part of the order was shipped via Boeing 747 air freighter to Luanda Quatro de Fevereiro International Airport, demonstrating DF Steel Pipe capability to support time-critical offshore oil and gas operations with expedited logistics.

1. Order Specifications and Technical Requirements for Deepwater OCTG

The Halliburton Angola order required OCTG casing pipes meeting stringent technical specifications appropriate for deepwater drilling conditions in Block 17, where water depths range from 600 to 1,500 meters and target reservoir depths extend to 5,000+ meters below the mudline. The N80-Q grade casing (OD 9-5/8", 53.5 lb/ft) was specified for intermediate casing sections requiring a balance of collapse resistance, burst strength, and axial load capacity under deepwater well conditions with external hydrostatic pressures exceeding 10,000 psi. N80-Q is a quenched and tempered grade with minimum yield strength of 80,000 psi and enhanced collapse resistance compared to standard N80, suitable for depths where collapse from external formation pressure is the primary design consideration for intermediate casing strings.

The L80-1 (13Cr) grade was specified for production casing sections exposed to produced fluids containing CO₂ at partial pressures exceeding 30 psi, where carbon steel would experience unacceptable corrosion rates. L80-1 with 13% chromium content provides a protective chromium oxide passive film on the pipe surface, reducing uniform corrosion rates by 1-2 orders of magnitude compared to carbon steel in sweet (CO₂-containing) production environments. The 13Cr material was manufactured to controlled chemistry with maximum sulfur and phosphorus limits of 0.010% each, ensuring hot workability and isotropic mechanical properties.

All casing pipes were supplied with BTC (Buttress Thread Casing) connections per API 5B, a widely-used threaded and coupled connection design providing reliable structural integrity and gas-tight sealing for casing strings where premium connections are not mandated by well design. BTC connections feature a trapezoidal thread form with 3/4-inch taper per foot on diameter, providing efficient load distribution and ease of field make-up. Drift testing per API 5CT confirmed full-bore access for subsequent drilling and completion operations.

2. Quality Control, Testing, and Material Traceability

Every casing pipe in the Halliburton order underwent a comprehensive inspection and testing protocol exceeding standard API 5CT requirements: (1) Hydrostatic Pressure Testing at 10,000 psi minimum (69 MPa), exceeding API 5CT minimum test pressure requirements, with 15-second hold and automated pressure-time recording at 100 Hz sampling; (2) Ultrasonic Electromagnetic Inspection using rotating UT/EMI probe heads with 32-channel phased array coverage, detecting longitudinal and transverse flaws, wall thickness variations, and laminations with 1.6mm FBH equivalent sensitivity; (3) Drift Mandrel Testing per API 5CT using full-length cylindrical drift mandrels confirming minimum ID throughout each pipe joint; (4) Thread Inspection using certified API thread gauges (plugs and rings) with standoff measurement, lead measurement, taper measurement, and height measurement per API 5B; (5) Phosphate Coating applied to coupling threads for anti-galling protection during field make-up; (6) Laser Marking of each pipe joint with heat number, grade, OD, weight, connection type, and unique joint serial number for full traceability from steel making through final dispatch.

Full EN 10204 Type 3.1 Material Test Certificates were provided for each heat of steel, including chemical composition (OES analysis), tensile testing (yield strength, ultimate tensile strength, elongation, Y/T ratio), Charpy V-notch impact testing at -20°C, hardness testing per ASTM E18 (HRC scale), and metallographic examination confirming tempered martensitic microstructure free of detrimental phases.

3. Angola Offshore Market Context and West Africa OCTG Demand

Angola is Africa second-largest oil producer after Nigeria, with production of approximately 1.1 million barrels per day (2026). The country deepwater and ultra-deepwater blocks — particularly Block 17 (operated by TotalEnergies), Block 15 (operated by ExxonMobil), and Block 32 — represent some of the most prolific oil-producing reservoirs globally. Sustained drilling activity across these blocks generates consistent demand for API 5CT OCTG casing and tubing, including J55/K55 conductor and surface casing, N80 intermediate casing, L80 production casing, and P110 high-strength casing for HPHT wells. Additionally, CRA (Corrosion Resistant Alloy) grades including 13Cr, Super 13Cr, and Duplex 22Cr/25Cr are increasingly specified for fields with high CO₂ and H₂S content as development extends into deeper, hotter, and more corrosive reservoir environments.

DF Steel Pipe successful execution of this Halliburton order — including the critical air freight logistics component — positions us as a reliable OCTG supplier for international oilfield service companies operating in West Africa deepwater basins. Our ability to manufacture to API 5CT specifications, perform comprehensive NDT and hydrostatic testing, provide full MTC 3.1 traceability, and execute expedited logistics to African destinations is directly applicable to future opportunities across Angola, Nigeria, Ghana, Equatorial Guinea, Congo, and Gabon.