mutilateral wells
DESCRIPTION
DIFTRANSCRIPT
QUICK FACTS Vincentisthefirstknownsubsea
development(worldwide)entirelybasedonamultilateralsystem.
FirstuseofsubseamultilateraltechnologyandtechniquesinAustralia.
Woodsidehasnowinstalled5xTriLateralsand8xBiLaterals.
Vincentwellsaredrilledupto2.5kmhorizontally(extendedreachdrilling)throughchallengingunconsolidatedsandswithina+/-1mdrillingwindow.
MULTILATERALWELLSLateralThinkingDrivesLowerCost| May2012
Woodside’scapabilitywithmulti-lateralhorizontalwellswascrucialontheVincentfielddevelopment.Itreducedcapitalexpenditurewhilstmaximisingreservoircontact.
WetookaprogressiveapproachinordertoovercomethechallengesoftheVincentfield.Akeyenablerwasdevelopmentofthefieldwithmultilateralwellstoimproveeconomicswhilstmaintainingrecovery.
WoodsidewasthefirstoperatorinAustraliatodrillandcompletemulti-lateralwellsandthefirstoperatorintheworldtodrilllarge-bore10¾”multilaterals.
TheVincentfieldisinshallowwater,thereservoir’soilcolumnisrelativelythinandspreadoverawidearea,theoilishighlyviscousandsandcontrolisanissue.
Woodside’sdrillingteampositionedwellswithpin-pointaccuracyinaverynarrowenvelopeoverdistancesofupto2.5kminthesandface.Addedtothat,highlyviscousoildoesn’tfloweasilywhichmeansdrillingmultiplewellstomaximiseoilrecoveryacrossthereservoir.
Technical Challenges:
Althoughtechnicallychallenging,themostcost-effectivemeansistodrilltheinitialsubseawell(motherbore)andthenbranchoffasecondwellpath(lateralbore)withinthereservoirusingawhipstock.
Thetwoboresarethenconnectedwithamultilateraljunction(RapidX)andthentheuppercompletionandsubseatreeareinstalled.
Commercial Benefit:
Addingalateralboreontoanexistingnewwellrequiresanincremental30%drillingandcompletioncapitalexpenditure.Creatingamultilateralwellalsoallowsfortheeliminationofasubseatreeanduppercompletionfortheadditionallateral.
ForfullfielddevelopmentonVincent(asshowninthediagrambelow)31lateralsweredrilled.However,only13uppercompletionsand13subseatreeswererequired.ByutilisingmultilateralwellsinthewaydescribedWoodside(anditsjointventurepartnerMitsui)reducedcostsby$1b.
MulitlateralTechnologyhasproventobeausefulenablertounlockreservesinfuturedevelopmentsforWoodside.
Inaworldwhereeasy-to-accesshydrocarbonsarebecomingrarer,thetechnicalcapabilitytoexploitdifficult-to-accessreservoirsisincreasinglyakeyfactorinaproject’sviability.
Areservoirsectionillustratingastandardwelltomultilateralwell