Wellheads and Christmas trees
API 6A specifies wellheads in five pressure classes from 2,000 psi to 20,000 psi and three temperature classes covering arctic to high-temperature service. A typical UAE land well is fitted with a 13-5/8" × 10,000 psi composite wellhead and a 4-1/16" × 10,000 psi Christmas tree with manual or hydraulic actuators on the master, swab, and wing valves. Material classes (AA, BB, CC, DD, EE, FF, HH) are selected by H2S and CO2 content; sour service (≥ 0.05 psi H2S partial pressure) requires NACE MR0175 / ISO 15156 compliance with hardness limits on all wetted parts.
Downhole tools and intervention
Production casing strings need packers (permanent or retrievable), production tubing (typically 3-1/2" or 4-1/2" L80 or 13Cr), subsurface safety valves (SSSVs to API 14A), gas-lift mandrels, and flow couplings. Workover and intervention rigs use slickline tools (gauge cutters, plugs, fishing tools), wireline-set bridge plugs, and coiled-tubing bottom-hole assemblies. Isovoltech sources from Halliburton, Schlumberger, Baker Hughes, Weatherford, and qualified independent suppliers.
Pipeline valves and components
API 6D pipeline ball valves dominate trunk-line and station service in the 4–48" diameter range; trunnion-mounted designs handle high-pressure (Class 600–1500) crude and gas duty, while floating ball valves cover utility service to Class 300. Gate valves (API 600 / 6D) are still specified for some refinery feed lines. Pipeline pigging stations require launchers and receivers with 4-way diverter valves, kickers, and through-conduit ball valves. Isolation joints (monolithic insulating joints) prevent stray-current corrosion across cathodic-protection boundaries.
Sour service and material selection
Sour gas (H2S-bearing) service drives material specification: NACE MR0175 caps hardness on carbon and low-alloy steels (typically ≤ 22 HRC for body and bonnet), requires impact testing per API 6A PSL3, and excludes free-machining steels. Higher-severity sour service uses 13Cr, super-duplex, or Inconel 625 wetted parts. Every wetted component arrives with mill test certificates (3.1 EN 10204) traceable from melt heat to finished part, plus PMI (positive material identification) verification on critical seats and stems.
API specifications quick-reference
| Component | Spec | Typical pressure | Sour service note |
|---|---|---|---|
| Wellhead / X-tree | API 6A | 5,000–15,000 psi | Material class CC/DD/EE/FF |
| Pipeline valve (ball) | API 6D | Class 150–1500 | Trim selection per H2S level |
| Process valve | API 600 / 602 | Class 150–2500 | 13Cr or super-duplex trim |
| Subsurface safety valve | API 14A | 5,000–15,000 psi | Always NACE MR0175 |
| Flange | ASME B16.5 / B16.47 | Class 150–2500 | Forging per A350 LF2 for low temp |
Frequently asked questions
What does API 6A class 'EE' mean?
API 6A material classes encode service severity. 'EE' means general service plus H2S-resistant, suitable for sweet crude with low-to-moderate H2S. 'FF' adds full sour service capability, 'HH' covers severe sour with hardness-controlled trim. Match the class to your reservoir fluid analysis.
Do you supply NACE MR0175-compliant equipment?
Yes — every wellhead, valve, flange, and bolting set destined for sour service ships with NACE MR0175 / ISO 15156 compliance certificates, hardness-test reports, and full material traceability.
What is the lead time on a 10,000 psi wellhead?
Standard 13-5/8" × 10,000 psi composite wellhead with API 6A class EE material is 14–18 weeks. Higher pressure ratings (15K) or H2 / sour-service material classes extend this to 20–26 weeks.
Can you supply API 6D pipeline pigs and pigging stations?
Yes — pig launchers and receivers, 4-way diverter and through-conduit valves, pig signallers, and the full range of foam, mandrel, and intelligent pigs.