Well Intervention & Testing

How the sub-Categories differ

Cementing units and casing equipment work on almost every well, so they are often part of the rig's own outfit. Wireline and test spreads tend to be sized for a specific campaign, which makes pressure class and sour service rating the first filters.

Standards across the group

• API Spec 6A for wellhead and flow control equipment. It sets pressure classes (2,000 to 20,000 psi), temperature classes, material classes AA to HH and product specification levels PSL 1 to 4.
• NACE MR0175 / ISO 15156 for any metal that sees hydrogen sulfide. Compliance depends on material, heat treatment and hardness, so it must be shown on the original records. You cannot add it later.
• ASME Section VIII or the EU Pressure Equipment Directive for separators, heater shells, tanks and air receivers.
• API Spec 8C and API RP 8B for hoisting equipment such as elevators, spiders and casing running tools. RP 8B sets inspection categories I to IV.
• API Spec 7K for power tongs and slips.
• API Spec 10A for well cements, and API Spec 10D and Spec 10F for centralizers and float equipment.
• API RP 16ST for coiled tubing well control equipment. It does not cover a wireline pressure control stack.
• DNV-ST-E271 (2.7-1) for offshore containers and DNV-ST-E273 (2.7-3) for portable offshore units such as service skids.
• IEC 60079, ATEX or IECEx for electrical equipment in Zone 1 or Zone 2 hazardous areas.

Pressure equipment comes first

Every part between the well and the first choke sees full shut-in pressure. Check that each valve, flowhead, manifold and piece of treating iron carries the same pressure class, or that the system is limited to its weakest part. Ask for dated hydrostatic test charts, the API Spec 6A material and temperature class, and relief valve test certificates. Mixed hammer unions are a known hazard. A 2 in Figure 602 and a Figure 1502 union can partly make up, and the lower-rated half fails under pressure, so check every union figure number against the iron rating.

Skids, lifting and hazardous areas

Offshore skids need a current certificate to DNV 2.7-1 or 2.7-3, or the equivalent your operator accepts, plus a lifting set with its own inspection record. Diesel engines that run in a hazardous area need air intake shutdown valves, spark arresting exhausts and surface temperature control. Electrical parts need Ex certificates that match their nameplates and the zone where they will sit.

Integration with the rig or vessel

• Deck space, deck load and crane capacity for the heaviest lift.
• Power supply voltage and frequency for electrically driven units.
• Rig air, water and bulk cement supply.
• Tie-in to the rig's emergency shutdown and fire and gas systems.
• Data links from acquisition systems to the rig or onshore centre.

Recertification and refurbishment

Pressure equipment is stripped, inspected for erosion and cracks, re-sealed and hydrostatically tested. Wall thickness surveys on piping and vessels confirm remaining corrosion allowance. Lifting equipment is recertified through an RP 8B Category III or IV inspection and a load test, and skids are re-inspected against their DNV certificate. Electrical equipment in hazardous areas goes to an approved repair facility. A used spread with current certificates suits a short campaign, and a refurbished one with fresh tests and lifting certificates reaches the rig with fewer audit findings. Naventr can arrange an inspection on request and pass on what the Seller's records show.