​​ Offshore Structures 612 – Fixed Structures Assignment 1. Objectives a) Develop a topsides layout to achieve a safe arrangement with required functionality and operational efficiency. The building blocks provided are drill rig, well bay area, process equipment, utilities equipment, accommodation modules, cranes, flare boom, helideck and lifeboats. The developed layout should have due consideration to prevailing weather conditions and installation method. Give reasons or explanation of all layout decisions. b) Select a substructure arrangement suitable for supporting the topsides developed in a) above. Require: Type and configuration of substructure; Level of underside of topside lower deck (provide calculation); Orientation wrt prevailing weather and topsides; If steel substructure, main plan levels; If steel substructure, suitable bracing pattern; Location of conductors and risers; Foundation concept. 2. Scenario The Timor-Leste government in collaboration with a major international oil and gas operator is planning to develop a gas field 150 km off the Timor-Leste coast. It is planned to separate the gas and condensate on a number of platforms and then pipe gas and condensate to a gas plant to be developed on the mainland. The water depth at the platform site is 140 meters. The planned approach is to develop the field in stages – platform A will be installed, wells drilled from an MPDR rig. Subsequent phase will involve a second platform which will make use of the MPDR when no longer used on Platform A. Estimated topside weight is 24,000 tonnes plus 3300 tonnes MPDR package load. 12 No. dry tree wells are to be supported on the platform. The conductors have been specified as 26" diameter. Export of gas is via a 24" export riser and condensate via a 10" line. The platform is planned to be not normally manned (NNM) but will require quarters for the duration of drilling and quarters for maintenance campaigns throughout its life. Site reports have concluded that the seabed consists of calcareous soils, suitable for piling and/or shallow foundations. 3. Information A spreadsheet is provided giving sizes of the key components. Rules are: • Helideck – D = 16m don't change • Lifeboats - no scaling • Well bay area – 12 well slots on 5m x 5 m grid. Ok to adopt a pattern 6x2 or 3x4 • Flare – stretch and modify as required. • Process space volume as given. It accounts for two trains so can divide in two to suit your arrangement. • Quarters – locate space for the required volume • Utilities – locate space for the required volume • Cranes – show locations, select one or two. • Deck structure – stretch or adjust dimensions to suit your layout. • Drill derrick, MPDR modules and pipe rack – Locate appropriate space. No scaling. Student may make use of the internet and make reasonable assumptions for any information not provided. All assumptions must be stated. 4. Assignment Deliverables • Sketches of topsides and substructure. Include plan, elevations in two orthogonal directions. Sketches to show topside and substructure orientation. • List of assumptions • List of reasons supporting your layouts • Any calculations undertaken.