海洋工程结构

第三章船舶与海洋工程结构形式§3-3.海洋工程结构一、几种典型平台的结构组成

二、海洋立管

一、几种典型平台的结构组成自升式平台：平台主体；桩腿（圆柱|桁架）；升降机构半潜式平台：上层平台；下浮体（或浮箱）；立柱和撑杆导管架平台：上部结构；导管架；桩二、海洋立管立管：连接钻井船或平台至水下井口的钢质管状结构。按用途可分为：DrillingCompletion/workover(similartoDrillingrisers)Production/injectionExport二、海洋立管钻井隔水管作用：为钻井液提供通道为钻杆从水面至井口导向组成：多节钢管连接而成，每支钢管两端有特制接箍。张紧器：提供张紧力，避免压屈。伸缩隔水管：随船体有4.6-9.1m的升沉。上下球接头：俄罗斯ZAO公司铝合金隔水管

俄罗斯ZAO公司采用铝合金(主要成分为Al-Zn-Mg和Al-Zn-Mg-Cu)作为隔水管材料,在满足强度要求的条件下,铝合金隔水管比钢制隔水管更轻,在平台承载能力不变的情况下,能够在更大水深的海域钻井。但是,ZAO公司隔水管采用的是法兰连接,下隔水管时效低,不能有效提高钻井效率。法国IFP和Framatome公司CLIP隔水管从20世纪80年代起,法国石油研究院(IFP)和Framatome公司就在开发CLIP隔水管,如图3~4。开发CLIP隔水管的主要目的是为了提供快速和安全连接的隔水管接头,来满足大直径、超深水钻井所需的高压力压井和节流管线的连接需要。目前,已经为PrideInternational公司制造了2套系统,PrideInternational公司已经在PrideAfrica和PrideAngola钻井船上使用。图4CLIP隔水管接头Cameron公司LoadKing隔水管系统LoadKing型法兰隔水管系统属于传统的钢制法兰式连接隔水管系统,如图5。由于采用法兰式连接,隔水管系统连接强度大,所以主要用来满足水深在3048m(10000英尺)或以上的超深水钻井的需求。该系统包括钻井隔水管、张力环以及承载1814•4t(4×106磅)载荷等级的伸缩接头锁紧系统。该系统可以和最高载荷等级的工业应用的卡盘、万向节和送入工具配套使用。

a隔水管b隔水管接头Low-pressureDrillingRiserDrillingrisersissubdividedintoLow-pressurerisers&high-pressurerisersThestandarddrillingrisertodayisalow-pressureriser,opentoatmosphericpressureatthetopend.Thustheinternalpressurecanneverexeedthatowingtothedrilling-mudweight.Low-pressureriserscompriseacentraltubeof21in.diameterandisequippedwithperipherallines.peripherallines:1)killandchokelines;2)boosterline3)hydrauliclineRiserjointisequippedwithsyntacticfoambuoyancymodulestoreducetheweightinwater.Low-pressureDrillingRiser1)killandchokelines,usedtocommunicatewiththewellandcirculatefluidintheeventofagaskickforwhichtheseafloorblowoutpreventer(BOP)hastobeclosed;2)boosterline,usedtoinjectedfluidatthelowendoftheriserandacceleratetheflowsoastobetterevacuatethecuttings.3)small-diameterhydraulicline,usedtopowertheseabedBOPperipherallines:peripherallinesareattachedtothemaintubebyseveralguides.Thesehavetobecarefullydesigned,sincetheypreventtheperipherallinesfrombucklingundertheeffectofinternalpressure.Low-pressureDrillingRiserJointsareequippedwithsyntacticfoambuoyancymodulestoreducetheweightinwater.Drillingrisersaregenerallyequippedwithsuchmodulesovertheupperpartoftheirlength.Ashortlengthclosetothesurfaceisusuallyleftbare,toreducehydrodynamicloadsinthezonewherethewaveforcesaregreatest.Thelowerpartoftheriserisalsooftenleftbare,sincethedensity(andcost)ofsyntacticfoamincreaseswiththerequireddesignpressure-andhencewithdepth.Low-pressurerisershigh-pressurerisersBOPislocatedatthesurfaceThisriserhasamuchsimplerarchitecturethandoesalow-pressuredriser,sinceitdoesnotrequirekillandchokelinesIntheeventofagaskick,theBOPisclosedatthesurface,whichisimmediatelyaccessieonthedrillingrig.Thustheriserhastobedesignedtotakefullwellpressure.Moreriskwhendrilling,unlessanadequateseabeddisconnectionsystemcanbeprovidedincaseofanemergency.ProductionrisersBundledrisers,flexiblerisers,top-tensionedrisers(TTRs),steelcatenaryrisers(SCRs)ExportrisersissimilartothoseofProduction/injectionrisers,butwithlargerdiametersandlowerpressures.BundledrisersEncompassesseveraldifferentriserarchitecturesInspiredbyarchitectureoflowerpressuredrillingrisers.Compriseacorepipewithanumberofsatelliteproductionresersaroundit,towhichitwasattachedbyguides.Thecentralcorepipealsoservedastheexportriser.EachsatelliteriserhaditsowntensionerflexiblerisersChangesinlateraloffsetoftheplatformtendedtoinducelargevariat