Tc 67/sc 4 n date: 2005-03-9 iso/wd XXXXXX ISO tc 67/sc 4/wg 6 Secretariat: Design of dynamic risers for offshore production systems Élément introductif — Élément central — Élément complémentaire Warning
Installation, Retrieval and Reinstallation of Other Risers
Download 2.34 Mb.
|
- Navigate this page:
- Maintenance and Inspections
- Tensioner System Maintenance
- Miscellaneous Inspections
- Operational and safety procedures
Installation, Retrieval and Reinstallation of Other RisersThe following is from Installation, Retrieval, and Reinstallation of Other Risers, Section 3.9, API-2RD-1998 First Ed.: In general, the riser classifications addressed in the preceding sections should cover the range of riser system types in current practice. There may be special features of a given riser system that may lead the designer to consider it unique in terms of configuration and/or service. For example, the riser system may be a hybrid riser that combines both metal and flexible pipe elements, or the riser may be considered as primary mooring element in addition to the role of conduit. In very deep waters, what may normally be considered rigid metal riser pipe sections may be configured such that the riser system has the inherent compliance more commonly associated with flexible risers. Examples are catenary risers, twisted pipe bundles or pre-buckled vertical S risers. In such cases, the designers may have to allow for special features or demands associated with unique installation or retrieval operations. Reference to other guidance documentation may be required. For example, risers providing both production and mooring service as riser/tendons would need to meet all the requirements of performing as a production riser and the additional requirements of acting as a mooring element (API RP 2T).
The following is from Maintenance and Inspections of Section 3.11, API-2RD-1998 First Ed.: Maintenance and inspection philosophyThe type and frequency of in-service maintenance of a riser needs to be balanced throughout the design process, since increases in robustness of design, or material quality, may lessen inspection and maintenance requirements. Regular monitoring of the riser system helps to provide a safe and trouble-free operation. Depending upon the water depth of the installation, subsea equipment inspection and monitoring can be carried out on a routine basis or when trouble is detected using either divers, ROV system, or guidewire run camera systems. Surface equipment should also be regularly inspected and monitored and a routine inspection/monitoring program be established. Planned or scheduled system maintenance and early detection of problems may save a great deal of time, especially in water depths beyond diver capability. Designers should ensure that inspection and renovation of tensioner components is facilitated by the system design. For example, all tensioner wires should be routinely visually checked for broken strands. A regular slip and cut program should be planned. Riser tensions should be monitored on a regular basis. Critical valve functions should be checked and locked off, if possible, to prevent inadvertent operation. Accumulator, cylinder and system inspection and maintenance should be performed routinely.
Riser InspectionsRoutine riser inspections should be performed for signs of leakage, corrosion or damage to the riser system and control equipment. The type and frequency of inspections should be established by the designer in consideration of system and component criticality. The riser can be inspected visually by a diver or ROV-deployed video or still camera system. NDE ultrasonic inspections can be performed on critical areas of the riser pipe. The use of this equipment and its interfacing to the riser system components and the ROV or diver should be established during the riser design. The riser cathodic protection (CP) system can be inspected by means of in-situ probes that measure the potential voltages of the surfaces to protect.
Miscellaneous InspectionsThe condition of the riser jumper hoses should be visually inspected for any signs of wear and damage from contact with the moonpool or other hoses or umbilicals. A method of replacement may need to be considered during production operations. Riser control umbilicals should be inspected regularly, as they can become entangled with the riser system. Marine GrowthRoutine inspections to ascertain the thickness and type of marine organisms on marine risers should be performed to identify if and when removal of the fouling is needed. Visual or ROV camera inspection is adequate to identify dimensions and trends. Length of time between inspections will be determined by environment and the tolerance in the riser design for increased loading due to the marine growth (see 6.3.5.3). Maintenance will consist of removing part or all of the marine growth when design tolerance is exceeded. Before selecting a marine growth removal procedure, its compatibility with the riser corrosion protection system should be determined. Candidate removal procedures include water jetting, mechanical brushing or scraping. TrainingThe following is from Training, Section 3.15, API-2RD-1998 First Ed.: Training programIn the case where the riser system needs to be run and retrieved frequently, a fully trained crew may be needed to safely and efficiently carry out the various riser operations that are required. Required personnel should be identified during the project construction phase. Qualifications should be developed and placed in the job descriptions of those who will work the riser systems. Specialists with marine operations or subsea and/or drilling backgrounds can be used or trained to carry out these duties. A strong effort should be made to involve operating personnel in the design, construction and commissioning phases.
Training manualsThe designer should develop a training manual for classroom instruction. This document should provide a quick reference to the equipment and describe procedures that need to be followed and why they are important. Operational and safety proceduresA full set of operational and safety procedures should be developed for all of the riser operations anticipated. These procedures should be updated as required and be tested if possible. Offshore commissioning phaseThe training program should ensure a trouble free and safe operation. During the pre-commissioning and commissioning phases, consideration should be given to making available experienced design engineers who can assist with onsite training of personnel. Riser operations personnel may have to be replaced or supplemented during the on-going production operation. New personnel should be given the necessary training on the riser operational and safety requirements. Directory: standards standards -> Request for proposal contract form for the transit industry standards -> Indiana Academic Standards Resource Guide Grade 8 United States History – Growth and Development (to 1877) Updated April 2016 standards -> Us history Dictionary Based on the sc state Standards standards -> Integrating Standards Education into the Business School Curriculum standards -> Use of Sprint U301 3G/4g mobile Broadband usb device Installation standards -> International organisation for standardisation organisation internationale de normalisation standards -> Standards of Excellence standards -> Common Core State Standards for Mathematics (ccssm) Download 2.34 Mb. Share with your friends:
|