Offshore Natural Resource Extraction

1. Offshore Natural Resource Extraction

2. Overview • History • Exploration • Seismic surveys • Drill ships • Platform models • Fixed Platforms • Compliant Towers • Semi-submersible Platforms • Jack-up Platforms • Tension-leg Platforms • Spar Platforms • Subsea Systems • Recent Affairs

3. History • 1986 - Companies drilled from piers extending off the beach at Summerland California • 1911 - Gulf Oil drilled the worlds first truly “offshore” well detached from the shore at Caddo Lake, Louisiana/Texas border • 1947 - Although drilling in the Gulf of Mexico has been taking place for some time, Kerr McGee completed first offshore well out of sight of land

4. 1965 – The 5600 ton drilling barge “Sea Gem” was first to discover hydrocarbons in the British North Sea sector

5. Exploration • Seismic Surveys • Maps rock layers without drilling a well • Send shockwaves using air guns and record echoes • The time for each echo to return as it bounces depends on depths and properties of rock layers • Problem: presence of hydrocarbons can only be confirmed by drilling

6. Drill Ships • Ship with oil derrick on deck • Used to quickly drill and check for hydrocarbons • Not as stable as other rigs • Very mobile

7. Early ships used anchors to maintain position • Modern vessels use Dynamic Positioning

8. Platform Models

9. Fixed Platform • Used in shallow waters up to 520m • Legs constructed of concrete or steel • Rest on their own masses, very stable in strong winds or rough waters • Designed for long term use • Concrete legs serve as storage tanks Gravity base platform being built in Norway

10. Jack-up Platforms • Moving legs attached to platform • Legs can be lowered like jacks and rested on seabed • Designed to easily move from place to place • Used in relatively low depths (up to 150m) • Problem: cannot be used in extremely deep waters

11. Compliant Towers • Similar to fixed platforms • Used in deeper waters ( 450 – 900m) • Slender tower attached to foundation slab on seabed • Very flexible compared to fixed platforms • Can sustain significant lateral deflection cause by water movement • Strong enough to withstand hurricanes despite it’s flexibility

12. Semi-submersible Platforms • Supported by hulls or pontoons • Can be ballasted up and down by regulating flooding in buoyancy tanks • Can be moved from place to place • Anchored by cable or dynamic positioning • Very stable in rough, deep seas • Used in depths from 180 – 1,800m

13. Tension-leg Platforms • Similar to semi-submersible, consisting of a floating rig • Attached to seabed by tethers • Tethers have high axial stiffness which eliminates most vertical movement • Used in depths of up to 2000 m • Miniature version called Seastar platforms are used in depths between 200 - 1100m

14. Examples of Seastar platforms

15. Spar Platforms • The largest of all platforms • Consist of a large cylinder used to stabilize the platform • Does not extend to the floor • Tethered by lines and cables • Unlike the TLP platforms it has conventional cables but is more stable due to the large ballast

16. -The Genesis hull, travelling past condominium complex in Port Arkansas, Texas

17. Subsea Systems • Do no have ability to drill • Extract and transport only • Used in depths of up to 2000m • Tied in to underwater pipeline or production platform • Avoids the need of production platform for each well

18. Summary

19. Recent Affairs

20. Hurricane Rita and Katrina Facts • 394 platforms in the path of the storms • 18 rigs suffered major damage or were totally lost • 16 rigs damage to varying degrees, up to 2 weeks to repair • Furthest rig drifted 80 miles during the storms • No loss of life

21. - Billiton Oil Platform Beached by Rita, just off of Dauphin Island, Alabama

22. Chevron’s TLP platform before the storms

23. - What remains of Chevron’s TLP platform after being hit by hurricane Rita

24. References • http://www.offshore-technology.com/projects/shtokman/images/image2.jpg • http://www.sv.vt.edu/classes/MSE2034_NoteBook/MSE2034_kriz_NoteBook/design_proj/ten_leg/tlp.gif • http://www.solentwaters.co.uk/Vessel%20Types/Vessel%20Types%204/_wp_generated/wp94c9b6c4.jpg • http://www.offshore-technology.com/projects/siri/ • http://www.mossww.com/mossmaritime/ • http://www.km.kongsberg.com/ks/web/NOKBG0239.nsf/obj/kristin_rig_200.jpg/$File/kristin_rig_200.jpg?OpenElement • http://www.jraymcdermott.com/images/jrme/compliant.jpg • http://en.wikipedia.org/wiki/Condeep • http://www.mms.gov/tarprojectcategories/deepwate.htm • http://dsc.discovery.com/fansites/oilsweatrigs/photo/photo_05.html • http://thomko.squarespace.com/display/ShowJournal?moduleId=209208&categoryId=35373 • http://www.solarnavigator.net/oil_rigs.htm • http://en.wikipedia.org/wiki/Oil_platform • http://www.naturalgas.org/naturalgas/extraction_offshore.asp • http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/offshore.html • http://science.howstuffworks.com/oil-drilling.htm • http://www.mms.gov/tarprojectcategories/Assets/Photos/abb.jpg

25. http://www.rigzone.com/data/rig_report.asp?rpt=reg • http://www.solentwaters.co.uk/Vessel%20Types/Vessel%20Types%204/page7.html • http://www.gomr.mms.gov/homepg/regulate/environ/louisiana_coast.html • http://www.schoolscience.co.uk/content/4/chemistry/petroleum/knowl/4/2index.htm?platforms.html • http://www.offshore-technology.com/projects/mensa/index.html#mensa6 • http://www.mustangeng.com/content.aspx?upstream_compliantpiledtowers • http://www.offshore-technology.com/projects/genesis/genesis3.html