简介:Stronghydrodynamicinteractionsduringtheside-by-sideoffloadingoperationbetweenfloatingliquefiednaturalgas(FLNG)andliquefiednaturalgascarrier(LNGC)caninducehighrisksofcollision.Theweathervaneeffectofasingle-pointmooringsystemnormallyresultsinthesatisfactoryhydrodynamicperformanceoftheside-by-sideconfigurationinheadseas.Nevertheless,thechangesinwavedirectionsinrealseaconditionscansignificantlyinfluencetherelativemotions.Thisarticlestudiestherelativemotionsoftheside-by-sidesystembyusingthetheoreticalanalysismethodandthenumericalcalculationmethod.Basedonthethree-dimensionalpotentialtheorymodifiedbyartificialdamping-lidmethod,thefrequency-domainhydrodynamiccoefficientscanbeimprovedtocalculatetheretardationfunctionsforthemulti-bodyproblem.Anin-housecodeisthendevelopedtoperformthetime-domainsimulationoftwovessels,throughwhichtherelativemotionsaresubsequentlyobtained.Arangeofobliquewavesarechosenfortheextensivecalculationofrelativemotionsbetweenthetwovessels,whicharefurtheranalyzedintermsofthephaseshiftofmotionresponsesinducedbyspecificresonantwavepatterns.Investigationresultsshowthatwavedirectionshaveasignificantinfluenceontherelativesway,roll,andyawmotions.Underthecircumstancethattheabsolutephaseshiftbetweentherollmotionsoftwovesselsapproaches180°,strongerrelativemotionsareinducedwhenLNGCisontheweatherside.Moreover,thegapwaterresonancesathighfrequenciestendtocausethedangerousopposedoscillationoftwovesselsintheswayandyawmodes,whereasFLNGreducesthegapwaterresonancesandrelativemotionswhenlocatedontheweatherside.
简介:ThispaperstudiesthecurrentavailableoptionsforfloatingproductionplatformsindevelopingdeepwateroilfieldsandthepotentialdevelopmentmodelsoffutureoilandgasexplorationintheSouthChinaSea.Adetailedreviewofcurrentdeepwaterplatformsworldwidewasperformedthroughtheexamplesofindustryprojects,andtheprosandconsofeachplatformarediscussed.Fourtypesofplatformsarecurrentlyusedforthedeepwaterdevelopment:tensionlegplatform,Spar,semi-submersibleplatform,andthefloatingproductionsystemoffloading.Amongthese,theTLPandSparcanbeusedfordrytreeapplications,andhavegainedpopularityinrecentyears.Thedrytreeapplicationenablestheextensionofthedrillingapplicationforfixedplatformsintofloatingsystems,andgreatlyreducesthecostandcomplexityofthesubseaoperation.Newlybuiltwettreesemi-submersibleproductionplatformsforultradeepwaterarealsogettingtheirapplication,mainlyduetothemuchneededpayloadfordeepwatermakingtheconversionoftheolddrillingsemi-submersibleplatformsimpossible.Theseplatformshavebeenusedindifferentfieldsaroundtheworldfordifferentenvironments;eachhasitsownadvantagesanddisadvantages.Therearemanychallengeswiththesuccessfuluseofthesefloatingplatforms.Alotoflessonshavebeenlearnedandextensiveexperienceaccumulatedthroughthemanyprojectapplications.Keytechnologiesarebeingreviewedforthesuccessfuluseoffloatingplatformsforfielddevelopment,andpotentialfuturedevelopmentneedsarebeingdiscussed.SomeofthetechnologiesandexperienceofplatformapplicationscanbewellusedforthedevelopmentoftheSouthChinaSeaoilandgasfield.