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American Petroleum Institute at the riser connector, allowing the riser tensioners to lift the riser clear of the stack. After disconnect, the vessel should be moved off the well location and guidelines slackened to prevent the heaving riser and LMRP from striking the BOP. If conditions permit, the riser and LMRP can be retrieved and stored on the vessel. Otherwise the riser should be raised as high as possible and hung off.
- 4.4.2 Emergency. Each rig should be equipped with written emergency disconnect procedures which account for various tubulars being in the BOP bore, peculiarities in the BOP and control equipment, and characteristics of position keeping or mooring equipment. An emergency disconnect is necessitated in the case of excessive vessel excursion from position over the wellhead or sometimes in the case of a blowout.
- 5 MAINTENANCE AFTER RISER RETRIEVAL.
After retrieval, the riser should be rinsed with fresh water, visually inspected, serviced and stored in accordance with the manufacturer's recommendations.
- 6 OTHER RISER SYSTEM MAINTENANCE.
- 6.1 Riser Tensioners. The tensioner piping should be checked for leaks before putting the system into operation. Visual checks of the system for hydraulic leaks and correct fluid level should be made periodically. Consult manufacturer's operation and maintenance guide for procedure and fluid type. Lubricate tensioner rods and determine a specific schedule to keep the exposed rods lubricated. Check sheave groove for wear, lubricate the idler sheave bearings and inspect bearing seals for damage. For wire rope systems, inspect wire line for broken strands and correct type per manufacturer's recommendation.
Take particular note of the wire condition at contact points with the sheaves during low heave operating conditions. When the limit of wireline life is approached, the line should be either cut and slipped to change the wear points, or replaced, to prevent wireline failure. When slipping the wire line, be certain that the lengths of line that were working over the sheaves before are not working over sheaves after slippage. Also, be certain that the tensioner ring clamp line attachments are secure and properly installed. A qualified re-termination procedure and personnel qualified for that procedure should be used. All the air pressure vessels should be regularly drained of any liquids as specified by the manufacturer.
4.6.2 Telescopic Joint. The inner barrel telescopes into the outer barrel and should be bolted or pinned to the outer barrel when handling.
Maintaining minimum pressure to effect a packoff will prolong the life of the packing element.
The telescopic joint should be inspected and serviced in accordance with manufacturer's recommendations.
- 6.3 Flex/Ball Joints. Flex/ball joints should have a protective cover at the upper neck to prevent the entry of cuttings and debris. The boot should be inspected prior to running, and replaced when necessary. Flex joints should be inspected to make sure the bore protectors and retaining studs and nuts are intact. After re trieval, wash all exposed surfaces with fresh water and inspect for both internal and external wear. A pressure-balanced ball joint should be tested in accordance with the manufacturer's recommendations to verify pressure integrity.
- 7 TRANSPORTATION, HANDLING, AND STORAGE.
- 7.1 General Handling and Storage. In general, marine riser components are made with precision parts that require careful handling. Protectors should be provided for the pin-end (and box-end if specified by the manufacturer) couplings of each riser joint. The couplings should be lubricated according to manufacturer's recommendations. The joints should always be handled individually and with protectors in place. Foam buoyancy material on risers is especially vulnerable to damage. If it is necessary to pick up and move the riser joints with a crane when automatic handling equipment is not available, a properly designed sling should be utilized. Handling slings should be designed to support the fully assembled riser joint. Telescopic joints typically weigh substantially more than riser joints and slings should be designed accordingly. Most riser joints are provided with lifting eyes located near the box and pin-ends for the sling attachments. Riser joints should not be lifted by choke, kill, or auxiliary lines or their brackets.
Caution should be exercised when stacking riser joints. When bare joints are stacked for shipping or storage, support shims should be provided under the bottom layer and between successive layers. The shims should be designed to prevent contact between adjacent joints. The weight of the joint should not be carried by unsupported sections of the choke or kill lines. Riser joints equipped with syntactic foam buoyancy may be stacked on top of each other without shims in accordance with the buoyancy manufacturer's recommendations.
4.7.2 Rig Storage Racks. To provide for adequate restraint and support for the riser during stored periods, riser storage racks or cradles should be used.
The design of the racks or cradles will vary with the specific constraints of the vessel and riser design; however, some guidelines can be stated.
- Cradles should be designed for supporting the weight of the riser, including all dynamic and environmental loadings.
- Support of buoyed riser joints should be made in accordance with the buoyancy manufacturer's specifications.
- No portion of the riser should be supported by the choke, kill, or auxiliary lines or their brackets.
- The racks should not hinder access to the pin and/ or box protectors or covers for maintenance and inspection.
- The racks should be able to support the riser and prevent load shifting for any expected list of the rig.
- 7.3 Land Base Storage. Riser joints should be stored with support shims under the bottom layer and
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