Offshore Natural Offshore Natural Resource Resource ExtractionExtraction

OverviewOverview HistoryHistory ExplorationExploration

Seismic surveysSeismic surveys Drill shipsDrill ships

Platform modelsPlatform models Fixed PlatformsFixed Platforms Compliant TowersCompliant Towers Semi-submersible PlatformsSemi-submersible Platforms Jack-up PlatformsJack-up Platforms Tension-leg PlatformsTension-leg Platforms Spar PlatformsSpar Platforms Subsea SystemsSubsea Systems

Recent AffairsRecent Affairs

HistoryHistory 1986 - Companies drilled from piers extending off the 1986 - Companies drilled from piers extending off the

beach at Summerland Californiabeach at Summerland California 1911 - Gulf Oil drilled the worlds first truly “offshore” 1911 - Gulf Oil drilled the worlds first truly “offshore”

well detached from the shore at Caddo Lake, well detached from the shore at Caddo Lake, Louisiana/Texas borderLouisiana/Texas border

1947 - Although drilling in the Gulf of Mexico has been 1947 - Although drilling in the Gulf of Mexico has been taking place for some time, Kerr McGee completed taking place for some time, Kerr McGee completed first offshore well out of sight of landfirst offshore well out of sight of land

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

ExplorationExploration Seismic Seismic

SurveysSurveys Maps rock layers Maps rock layers

without drilling a wellwithout drilling a well Send shockwaves using Send shockwaves using

air guns and record air guns and record echoes echoes

The time for each echo The time for each echo to return as it bounces to return as it bounces depends on depths and depends on depths and properties of rock layersproperties of rock layers

Problem: presence of Problem: presence of hydrocarbons can only hydrocarbons can only be confirmed by drillingbe confirmed by drilling

Drill ShipsDrill Ships Ship with oil derrick on deckShip with oil derrick on deck Used to quickly drill and check for hydrocarbonsUsed to quickly drill and check for hydrocarbons Not as stable as other rigsNot as stable as other rigs Very mobileVery mobile

Early ships used anchors to maintain positionEarly ships used anchors to maintain position Modern vessels use Dynamic PositioningModern vessels use Dynamic Positioning

Platform ModelsPlatform Models

Fixed PlatformFixed Platform Used in shallow waters up Used in shallow waters up

to 520mto 520m Legs constructed of Legs constructed of

concrete or steelconcrete or steel Rest on their own masses, Rest on their own masses,

very stable in strong winds very stable in strong winds or rough watersor rough waters

Designed for long term useDesigned for long term use Concrete legs serve as Concrete legs serve as

storage tanksstorage tanks

Gravity base platform being built in Norway

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

waterswaters

Compliant TowersCompliant Towers Similar to fixed platformsSimilar to fixed platforms Used in deeper waters ( 450 Used in deeper waters ( 450

– 900m)– 900m) Slender tower attached to Slender tower attached to

foundation slab on seabedfoundation slab on seabed Very flexible compared to Very flexible compared to

fixed platformsfixed platforms Can sustain significant Can sustain significant

lateral deflection cause by lateral deflection cause by water movementwater movement

Strong enough to withstand Strong enough to withstand hurricanes despite it’s hurricanes despite it’s flexibilityflexibility

Semi-submersible PlatformsSemi-submersible Platforms Supported by hulls or pontoonsSupported by hulls or pontoons Can be ballasted up and down by regulating flooding in Can be ballasted up and down by regulating flooding in

buoyancy tanksbuoyancy tanks Can be moved from place to placeCan be moved from place to place Anchored by cable or dynamic positioningAnchored by cable or dynamic positioning Very stable in rough, deep seasVery stable in rough, deep seas Used in depths from 180 – 1,800mUsed in depths from 180 – 1,800m

Tension-leg Tension-leg PlatformsPlatforms Similar to semi-submersible, Similar to semi-submersible,

consisting of a floating rigconsisting of a floating rig Attached to seabed by tethersAttached to seabed by tethers Tethers have high axial stiffness Tethers have high axial stiffness

which eliminates most vertical which eliminates most vertical movementmovement

Used in depths of up to 2000 mUsed in depths of up to 2000 m Miniature version called Seastar Miniature version called Seastar

platforms are used in depths platforms are used in depths between 200 - 1100mbetween 200 - 1100m

Examples of Seastar platformsExamples of Seastar platforms

Spar PlatformsSpar Platforms The largest of all platformsThe largest of all platforms Consist of a large cylinder Consist of a large cylinder

used to stabilize the platformused to stabilize the platform Does not extend to the floorDoes not extend to the floor Tethered by lines and cablesTethered by lines and cables Unlike the TLP platforms it has Unlike the TLP platforms it has

conventional cables but is conventional cables but is more stable due to the large more stable due to the large ballastballast

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

Subsea SystemsSubsea Systems Do no have ability to drillDo no have ability to drill Extract and transport onlyExtract and transport only Used in depths of up to 2000mUsed in depths of up to 2000m Tied in to underwater pipeline or production platformTied in to underwater pipeline or production platform Avoids the need of production platform for each wellAvoids the need of production platform for each well

SummarySummary

Recent AffairsRecent Affairs

Hurricane Rita and Katrina FactsHurricane Rita and Katrina Facts 394 platforms in the path of the storms394 platforms in the path of the storms 18 rigs suffered major damage or were totally lost18 rigs suffered major damage or were totally lost 16 rigs damage to varying degrees, up to 2 weeks to repair16 rigs damage to varying degrees, up to 2 weeks to repair Furthest rig drifted 80 miles during the stormsFurthest rig drifted 80 miles during the storms No loss of lifeNo loss of life

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

Chevron’s TLP platform before the storms

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

ReferencesReferences http://www.offshore-technology.com/projects/shtokman/images/imagehttp://www.offshore-technology.com/projects/shtokman/images/image

2.jpg2.jpg http://www.sv.vt.edu/classes/MSE2034_NoteBook/MSE2034_kriz_Nothttp://www.sv.vt.edu/classes/MSE2034_NoteBook/MSE2034_kriz_Not

eBook/design_proj/ten_leg/tlp.gifeBook/design_proj/ten_leg/tlp.gif http://www.solentwaters.co.uk/Vessel%20Types/Vessel%20Types%204http://www.solentwaters.co.uk/Vessel%20Types/Vessel%20Types%204

/_wp_generated/wp94c9b6c4.jpg/_wp_generated/wp94c9b6c4.jpg

http://www.offshore-technology.com/projects/siri/http://www.offshore-technology.com/projects/siri/ http://www.mossww.com/mossmaritime/http://www.mossww.com/mossmaritime/ http://www.km.kongsberg.com/ks/web/NOKBG0239.nsf/obj/kristin_righttp://www.km.kongsberg.com/ks/web/NOKBG0239.nsf/obj/kristin_rig

_200.jpg/$File/kristin_rig_200.jpg?OpenElement_200.jpg/$File/kristin_rig_200.jpg?OpenElement http://www.jraymcdermott.com/images/jrme/compliant.jpghttp://www.jraymcdermott.com/images/jrme/compliant.jpg http://http://en.wikipedia.org/wiki/Condeepen.wikipedia.org/wiki/Condeep http://www.mms.gov/tarprojectcategories/deepwate.htmhttp://www.mms.gov/tarprojectcategories/deepwate.htm http://dsc.discovery.com/fansites/oilsweatrigs/photo/photo_05.htmlhttp://dsc.discovery.com/fansites/oilsweatrigs/photo/photo_05.html http://thomko.squarespace.com/display/ShowJournal?moduleId=2092http://thomko.squarespace.com/display/ShowJournal?moduleId=2092

08&categoryId=3537308&categoryId=35373 http://www.solarnavigator.net/oil_rigs.htmhttp://www.solarnavigator.net/oil_rigs.htm http://en.wikipedia.org/wiki/Oil_platformhttp://en.wikipedia.org/wiki/Oil_platform http://www.naturalgas.org/naturalgas/extraction_offshore.asphttp://www.naturalgas.org/naturalgas/extraction_offshore.asp http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/offshohttp://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/offsho

re.htmlre.html http://science.howstuffworks.com/oil-drilling.htmhttp://science.howstuffworks.com/oil-drilling.htm http://http://www.mms.gov/tarprojectcategories/Assets/Photos/abb.jpgwww.mms.gov/tarprojectcategories/Assets/Photos/abb.jpg

http://http://www.rigzone.com/data/rig_report.asp?rptwww.rigzone.com/data/rig_report.asp?rpt==regreg http://www.solentwaters.co.uk/Vessel%20Types/Vessel%20Types%204http://www.solentwaters.co.uk/Vessel%20Types/Vessel%20Types%204

/page7.html/page7.html http://www.gomr.mms.gov/homepg/regulate/environ/http://www.gomr.mms.gov/homepg/regulate/environ/

louisiana_coast.htmllouisiana_coast.html http://www.schoolscience.co.uk/content/4/chemistry/petroleum/http://www.schoolscience.co.uk/content/4/chemistry/petroleum/

knowl/4/2index.htm?platforms.htmlknowl/4/2index.htm?platforms.html http://www.offshore-technology.com/projects/mensa/http://www.offshore-technology.com/projects/mensa/

index.html#mensa6index.html#mensa6 http://www.mustangeng.com/content.aspx?http://www.mustangeng.com/content.aspx?

upstream_compliantpiledtowersupstream_compliantpiledtowers http://www.offshore-technology.com/projects/genesis/genesis3.htmlhttp://www.offshore-technology.com/projects/genesis/genesis3.html