Frigg Field Case Study

Frigg playing rural area Case StudyCUTTING AND remotion OF PLATFORM FOUNDATIONSCallum Toole 201662274Antonios Poulis 201685557Marinos Mavroulis 201667892Abraham Ejiro Ibodje 2016531571.1 NORTH oceanSince the first steel piled jacket bum (SPJF) was installed in the northwards ocean in 1967 on that point has been a positive of 556 installed and 52 cod been decommissioned after operational role. The operational water insight of the pairing Sea varies as SPJF are split into small and macroscopic categories. Of the schoolmaster 556 foundations 392 were installed in water depths of less than 55m leaving 164 foundations orbital cavitying to depths of 190m (Oil foul up UK, 2012) (Offshore-mag, 2000).With oil and gas reserves depleting in this area more and more creations are applying for cease of production (CoP) to begin the decommissioning cycle. It has been estimated that over the next 25 years there impart be 35bn spent on decommissioning practise in the northwestwar d Sea alone (Decom North Sea, 2014).1.2 CASE demand FRIGG FIELDThe Frigg subject field is situated in the North Sea with 6 differing fixed foundation structures spread over UK and Norwegian blocks 10/1 and 25/1 respectively. These fixed foundations are a mixture of SPJF and gloom Based Structures (GBS). For the remainder of this assignment the Frigg Field case study will only consider the cutting and remotion of DP2 an 8 complication SJPF which back up a boring and production program Figure 2, (Total, 2003).Key aspects of the Frigg Field DP2 to be considered areWater depth 98m (321.5ft)Production depth 1850m (6070ft)24 considerablys drilled in total for production20 original steel pile foundations (4 external at each corner leg and 4 internal at inner legs) (T Gram, 2011) at 60 diameter (Total, 2003)Jacket recovery via re-float technique after victorful installation of airiness and cutting of foundationsIn the North Sea, the selection of the ROV system is vital to its success of the cutting and remotion of the DP2 jacket foundations. This is over collect to the ever-changing dynamic oceanward environment that effect cutting, lifting and removal of subsea infrastructure.2.1 ROV UNITThe Oceaneering Millennium plus (OMP) 220hp good pretend class ROV was selected for the cutting and removal of the Frigg DP2 foundations referable to its operational capabilities. The ROVs operative class design permits for front assembled three-fold operators to be interactive with the line of bailiwick in hand. Weighing in at 4,000kg the OMPs dimensions are 3.31.71.9m (LxWxH) (Oceaneering, 2017).The depth capabilities of the ROV pass away the depth needed to fully operate in the North Sea conditions at the Frigg lay as it is rated for up to depths of 3,000m. A main consideration of the OMP is its station keeping abilities and dual hydraulic units of 110hp powering 4 vectored horizontal and 4 unsloped propulsion units. This bequeaths for 2,000lbs of t hrust to be employ in the lateral, former and reverse directions with a vertical thrust of 2,800lbs.2.2 VISIBILITY TOOL interactionAnother main consideration of the ROV selected is its ability to interact clearly with tooling and structures at the water depth. This is do possible by the dual manipulators having 5 degrees of conk start which is powered by a 24V DC and 110V AC power append on board. To successfully clear, cut and remove the 20 pile foundations the OMP is assorted enough to interact with serious duty tools to do the jobs of dredging, cutting and use its manipulators to fit buoyancy jakess within 15 mm tolerance for removal trading trading trading trading operations (Oceaneering, 2017) (Total, 2011).The OMP will be interacting with a standalone subsea dredge and an External bang-up Tool when at operational depths. But also has the ability to be fitted with various skid pans if needed. The electroshock therapy selected for the cutting operations of the p ile foundations is an gravelly water jet cutting approach due to its multi-dimensional clamp configurations that allow for various diameters form 16 72 pipe to be cut.This is made possible by 8 fully mounted 250W high inspiration LED lighting units surrounding the front facing operating area working in conjunction with visuals. The visual knocked out(p)put of the OMP comes from tv cameras which can any be standard, high or 3D high definition (HD) - 3D HD is preferred for the operations due to enhanced visuals allowing for a safer more good operation.2.3 NAVIGATIONAutomatic controls for the OMP are used via fly by equip systems that allow for station keeping regarding depth, flip, tiptop and automatic pre-programmed headings. To allow for the altitude and headings to be correct a surveying grade gyro and allayer fluxgate compass is available on board the ROV. Depth of the ROV unit is vital due to the foundations being at seabed train and to avoid collisions with the seabed and/or cuttings pilings in the area (Oceaneering, 2017).2.4 LAUNCH AND RECOVERY SYSTEM (LARS)The adaptability of the OMP with regards to diverse LARS allows it to be used with multiple possible watercrafts when on site. There are various options available for the OMP heavy weather over boarding, A-frame, cursor and heavy lift winching.To safely and successfully drive and recover the OMP an A-frame system was selected. This is due to its simplicity, lifting capabilities and cost reduction during mobilisation at a new site or location.2.5 TETHER MANAGEMENT SYSTEM (TMS)During under water operations the OMP can work either free swimming or via a TMS. Free swimming operations are directly connected to the ROV transmit electrical power, mechanical payloads and optical signal by means of a tether during operations. A TMS configuration includes the use of a side founding garage or a Top-hat connection where the topside umbilical is connected and hence redistributes the power and sign als to the ROV via a tethered connection.During this operation at the Frigg Field a Top-hat TMS would be used to guide, control and position the OMP throughout its cutting and removal operations. This is due to strong advantages such as providing protection to the OMP as it is firm connected during tack together and recovery, secure positioning reduces complications at splash geographical zone interaction, the addition of the Top-hat TMS allows for a further working radius from the garage kinda than free swimming operations and allowing for greater precision on deployment to the work site.A characteristic mission for the OMP varies depending on the level of cutting and removal of foundations during decommissioning operations. Regarding the case study adopted for the Frigg Field the typical mission anticipate would be as followsEnvironmental checks would be carried out on the vessel to determine there is safe working conditions for the OMP to operateOMP and top-hat configurati on would be connected and moved to launch platform of the A-frame last checks of OMP before launchLaunching and lowering of the OMP (via A-frame) into the water through the splash zone monitor tension on the lineGrounding at operational level of 98mSubsea pressure and containment checks then release from top-hat configurationMovement towards and interaction with dredging equipment via manipulatorsDredging work carried out with standalone subsea dredge on completion the tooling would be removed review article of pile surfaces to be cut via front mounted camerasInteraction with ECT cutting equipment via manipulatorsAttachment of ECT cutting equipment to initial foundations monitoring work load from visualsInteraction with buoyancy sections being used for re-float x4 interaction, manipulation, fastening and final checksFinal checks of whole system and foundation structure before final oodles are cutAttachment of ECT cutting equipment for final cuts x4 carried outMonitoring the f loating of the jacket structure and buoyancy module interaction via visualsFinal checks of the seabed environment and coverage of unburied foundationsRecovery operations via the top-hat configuration and light to surfaceChecks, assessment and attention of the ROV reportedHaving selected the OMP for the decommissioning and removal of the DP2 SPJF there are various areas that may cause difficulties during the installation, operating and maintaining the OMP.4.1 SEA STATES WAVE AND CURRENTSIn the Frigg field, the average speed of wind between the spend months December to February is about 9.9 m/s. For this wind velocity, waves are most believably to have a maximum height of 2.5m. However, during severe winter storms which occur roughly once per decade in the area, there is a satisfying possibility of wave average heights from 12.1m and maximum height of 24m. Currents do fluctuate, reliant on the speed and direction of the winds (Total, 2003).With these environmental considerations in the North Sea it was necessary to choose an ROV with high performance thrusters to aid in station keeping whilst operating. The OMP permits this with four powerful vectored horizontal and four vertical thrusters, which allow the system to move in four directions, vertical, lateral, roll and pitch comfortably with 2,000lbs of thrust available (Oceaneering, 2017).4.2 LAUNCH AND RECOVERY OPERATIONSDuring launch and recovery operations there are expected difficulties such asLarge waves and high winds can cause the OMP and Top-hat TMS to swing wildly potentially impacting the vessel and causing damage to equipmentDifficult deployment and recovery procedures when there a reduced deck space to accommodate the operationOn drilling rigs the proximity of the OMP and Top-hat to the vessels hull and thrusters during entry and exit into the splash zone can become complicatedDeployed extension cables can be required to reach satellite sites where it was not practical or possible to install v ia the Top-hat TMS4.3 useable CUTTINGSOperational drill cuttings can be problematic with the removal of platform foundations due to its chemical makeup and mass surrounding the foundations at the sea bed. With the DP2 platform, 24 wells were drilled in total with an estimated upheaval of contained in an area of 80m x 120m at a maximum thickness of 20cm. due to the low toxicity of the drilling mud used the cuttings can be removed and treated (Total, 2003). To combat this the OMP is capable of using a complete 12 subsea dredge which can manipulate the suction nozzle aiding in the removal of drill cuttings and sediment surrounding the foundations before cutting operations (Oceaneering delirium tremens, 2013).5.1 OIL GASThe OMP can be used for different operations in the oil gas industry such as descryion, victuals and repair, installation, workover and control system (IWOCS), surveying, dredging, subsea tie-ins, flow assurance checks, assisting in the removal of subsea producti ons systems, post line servicing, cable laying operations, video servicing, acoustic positioning and sock intervention. Such operations like these can take place in the deep-water environments up to 3,000m maximum operational depths of the OMP.With respect to maintenance, repair and installation operations, the OMP has the capacity of transferring hot tap fittings, pipeline clamps, misalignment ball connectors, swivel-ring flanges, breakaway joints, riser connections and other equipment for delivery, repair and installation.Trenching burial of pipes and cables are operations that are carried out by ROVs that have 200hp and above. The OMP can be considered for these types of laying and burial operations due to its classification and strengthened in features (Oceaneering, 2017).One of the challenges facing operations in the offshore wind farm environment is observation and maintenance of fixed foundation based, cable monitoring, structural integrity checks and seabed surveys, th e OMP is well suited to address these issues due to its comprehensive build, mostly in winter and less visible conditions (submergedVision, 2017).5.2 FRIGG FIELD VERSATILITYDuring the decommissioning operation of the DP2 jacket it became aware that supererogatory preparation in cutting and removal of pile guides was needed to successfully fit and mount the buoyancy cans for removal. A solution to this was that a custom-built diamond wire tool and buoyancy solution was designed for operations to be carried out by ROV. With the OMP this could be successfully carried out due to its adaptability and tooling interaction (Proserv, 2017).5.3 OCEAN SCIENCEThe OMP can be used for scientific research under water such a sea creature and plants studies in natural environment, Arctic operations, if equipped with various sampling devices. Also, as it is equipped with 3D HD Camera (highly intensity LED) it can operate in extreme environments. Another strong versatile function is that it could b e used for underwater interactions documentaries, filmmaking, archaeology projects, e.g. Mystery Mardi Gras shipwreck (Landis, 2017).5.3 MILITARYThe Millennium Plus vehicle optional power/ data interfaces (Ethernet/optical fibre) and other features built in it can be used for naval/military operation, in the main for mine hunting and mine breaking. Neutralizing and retrieving of explosives, moored mines and also inspection tasks like meteorology, perception of environmental hazard, port security, mine countermeasure and maritime intelligence.5.4 FISHERIES AND AQUACULTUREThe over exploitation of the North Sea remains a highly-discussed topic to date to combat this there has been a growing market for offshore fish farms. A typical mission would involve the OMP to either help install or inspect and monitor fish inside, inspect netting/cages that have been used for containment. The manipulator operability would allow for heavy cages to be moved into place and fastened securely whil st clearly visual (R. D. Christ, 2014),The OMP can perform a widespread ladder of activities however there is still the possibility for make betterments that may be considered for upcoming development and improved efficiency.6.1 VISUALCurrently the OMP can be fitted with either Standard Definition (SD), High Definition (HD) or a 3D HD camera. For improved visibility during decommissioning operations and dredging procedures where the water conditions could be blurred due to sediment, an upgrade to a 4K Ultra HD camera would be beneficial. The light predisposition and quality of video produced would offer the OMP user a confidence horizontal when the seabed conditions are not clear to operate. The upgraded camera can be fitted with some more technical specifications such as noise reduction, a wider area of view and higher contrast. With these camera upgrades, the user will have less misrepresentations and even better situation and spatial awareness.6.2 POWER create THRUST CAPAB ILITIESImproving the hydraulic power units on board to 2 x 125hp would allow for an increase in 300lbs of thrust in the vertical, lateral, prior and reverse directions this would allow for the OMP to improve its station keeping abilities, be speedy during launch and recovery, manoeuvre heavier standalone tools and extra up thrust would allow the OMP to return to the surface with heavier loads more efficiently.6.3 MANIPULATORSIncreasing the manipulators range of motion would allow for more detailed technical operations to be carried out and improve the pilot/ROV interaction. This could be made possible by improving the dual manipulators to have 7 degrees of function and mounting a wrist camera assembly to improve visibility (Oceaneering, 2017). A manipulator that could be considered could be the TITAN 4 with its 7 degrees of motion, titanium material characteristics to reduce burthen and titanium wrist mounted camera to increase visibility (FMC Technologies, 2017).Decom North Sea, 2014. Decommissioning in the North Sea Review of Decommissioning Capacity, s.l. Decom North Sea.FMC Technologies, 2017. http//www.f-e-t.com. Online on hand(predicate) at http//www.f-e-t.com/images/uploads/Schilling_Titan_4_with_Spares_Kit.pdfAccessed 4 butt against 2017.Landis, N., 2017. Naultilus Productions. Online unattached at http//nautilusproductions.com/projects/mystery-mardi-gras-shipwreck-documentaryAccessed 4 March 2017.Oceaneering DTS, 2013. DTS Tooling. Online Available at http//www.oceaneering.com/oceandocuments/brochures/subseaproducts/Oceaneering-DTS-Catalog-2013.pdfAccessed 4 March 2017.Oceaneering, 2017. http//www.oceaneering.com. Online Available at http//www.oceaneering.com/oceandocuments/brochures/rov/ROV%20-%20Nexxus.pdfAccessed 4 March 2017.Oceaneering, 2017. Millennium Plus 220hp heavy work class ROV. Online Available at http//www.oceaneering.com/oceandocuments/brochures/rov/ROV%20-%20Millennium%20Plus.pdf Accessed 4 March 2017.offshore Energy Today, 201 2. http//www.offshoreenergytoday.com. Online Available at http//www.offshoreenergytoday.com/tag/ocean-installer/page/2/Accessed 10 March 2017.Offshore-mag, 2000. Offshore-mag.com. Online Available at http//www.offshore-mag.com/articles/print/volume-60/issue-8/news/two-part-kvitebjoslashrn-jacket-will-break-north-sea-water-depth-record.htmlAccessed 19 Feb 2017.Oil turgidity UK, 2012. Oil Gas UK The Decommissioning of Steel Piled Jackets In the North Sea Region, s.l. Oil Gas UK.Proserv, 2017. http//www.proserv.com. Online Available at http//www.proserv.com/media/case-studies/decommissioning/frigg-field/Accessed 4 March 2017.R. D. Christ, R. L. W., 2014. The ROV Manual A User hap for Remotely Operated Vehicles. 2nd ed. Waltham Elsevier.stevo6187, 2017. imagala.com. Online Available at http//www.imagala.com/post/1X5SEdD4ZDAccessed 4 March 2017.T Gram, R. K. J. K. M. J. E. K. C. H. A. S., 2011. Decommissioning of Frigg and MCP01 A Contractor View. Offshore Technology Conference, Volume 21708.Total, 2003. Frigg Field Cessation Plan, Stravanger Total.Total, 2011. Frigg Field Cessation Plan Close Out Report, s.l. Total.UnderwaterVision, 2017. Underwater Vision. Online Available at http//www.underwatervision.co.uk/services/wind-farms-and-offshore/Accessed 4 March 2017.