Case study: Supplying specialised valves for BP's Chirag flowline programme

Customer: BP Caspian
Destination: Azerbaijan
Project: Chirag Gas Lift / Flowlines

BP has operated in the Caspian region since 1992 and leads major offshore exploration and development projects out of Baku, including the Azeri-Chirag-Deepwater Gunashli field. As part of the Chirag flowline programme, Colson Valves supplied a 1" Class 2500lbs Double Block and Bleed valve, engineered to match an existing installation and manufactured to Norsok specification at Colson's Rotherham facility.

In this case study, Colson Valves outlines exactly what the project entailed.

The challenge

The project called for a 1" reduced bore Double Block and Bleed valve, Class 2500lbs, to a demanding specification. The valve required A350 LF2 body material to Norsok requirements, sourced from European origin, and PEEK seats with tungsten carbide (TCC) coated balls. A double O-ring stem design was needed above Class 900lbs, along with a 6mm OSY (outside screw and yoke) needle valve bonnet. The face-to-face dimension had to match the existing installation exactly, at 424mm, and the valve had to comply with BP's GIS-62-025 specification for double block and bleed valves. The build also called for extended hydrostatic and gas testing – including tests at 5% and 50% of rated pressure – together with non-destructive examination (NDE), ultrasonic testing (UT) and positive material identification (PMI), and paint finished to BP's offshore specification GIS-06-604.

The solution

Colson delivered a valve that met every technical requirement within a 10-week lead time. Materials were sourced through a Norsok-approved route from European origin, and the 424mm face-to-face was held precisely, avoiding rework to the existing pipework and welding. The balls were TCC-coated with PEEK seats – the longest lead-time item on the build. The valve passed the full extended hydrostatic and gas test regime, including the specified 5% and 50% rated pressure tests, and met the updated GIS-62-025 specification. It was witness tested by an independent third party. Bodies were manufactured in-house, from raw material through to final inspection and packing.

Specification

• Type: Modular Double Block & Bleed, floating ball
• Series: DMB
• Configuration: Ball / OSY Needle / Ball
• Inlet/Outlet: 1" Class 2500lbs RTJ (ring-type joint)
• Vent: ½" NPT female, ASME B1.20.1, double O-ring vent plug fitted
• Main bore: 19mm / Vent bore: 8mm
• Body/flanges: ASTM A350 LF2 to NACE MR-01-75 / ISO 15156
• Trim: ASTM A479 316
• Needle valve tip: Stellite 6
• Springs: X718
• Seats: PEEK
• Ball: ASTM A479 UNS S31803, tungsten carbide coated
• Seals: FKM (double O-ring) / graphite
• Operator: Lockable lever isolation, lockable handwheel vent
• Pressure rating: Class 2500lbs
• Fire-safe: ISO 10497
• Bolting: A320 L7M / A194 Gr 7ML, fluoro carbon coated
• Face-to-face: 424mm
• Raw material origin: EU

The valve was designed, machined, assembled and tested under one roof at Colson's Rotherham facility. Full EN10204 3.1 material traceability, together with compliance with internationally recognised standards, meant the valve was ready to perform offshore, on schedule.

At Colson Valves, our reputation is built on consistently doing what we say we will. We give realistic lead times, flag problems early, and deliver what we promise. It sounds straightforward, but in industries where supply chain failures are common, it makes a real difference. That is why our customers come back to us, project after project, year after year.

To discuss your next project, visit www.colson.co.uk or call +44 (0)114 492 0198.

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