简介:Aseriesofidealizedmodelsimulationsareanalyzedtodeterminethesensitivityofmodelresultstodifferentconfigurationsofthelateralboundaryconditions(LBCs)insimulatingmesoscaleshallowconvectionoverhillyterrain.Inthesimulationswithsteadythermalforcingatthemodelsurface,aradiationconditionatbothboundariesisthebestchoiceunderhighwindconditions,andthebestresultsareproducedwhenboththenormalvelocitiesandthetemperaturearetreatedwiththeradiationschemeinwhichthephasespeedisthesamefordifferentvariables.Whenthebackgroundwindspeedisreasonablysmall,theLBCconfigurationwitheithertheradiationorthezerogradientconditionatbothboundariestendstomakethenumericalsolutionunstable.Thechoiceofaconstantconditionattheinflowboundaryandaradiationoutflowboundaryconditionisappropriateinmostcases.Inthesimulationswithdiurnalthermalforcingatthemodelsurface,differentLBCschemesarecombinedtogethertoreducespurioussignalsinducedbytheoutflowboundary.Aspecificationinflowboundarycondition,inwhichthevelocityfieldsattheinflowboundaryareprovidedusingthetime-dependentresultsofasimulationwithperiodicLBCsoveraflatdomain,istestedandtheresultsindicatethatthespecificationconditionattheinflowboundarymakesitpossibletouseasmallermodeldomaintoobtainreasonableresults.Themodelhorizontaldomainlengthshouldbegreaterthanacriticallength,whichdependsonthedomaindepthHandtheanglebetweengravitywavephaselinesandthevertical.Anestimateofminimumdomainlengthisgivenby[(H-zi)/πU]√N2L2x-4π2U2,whereNandUarethebackgroundstabilityandwindspeed,respectively,Lxisthetypicalgravitywavelengthscale,andziistheconvectiveboundarylayer(CBL)depth.
简介:ProcessofsourcedynamicsoftheJingtaiearthquake(M=6.2)Xue-BinDU(杜学彬);Zhi-DeYAN(闫志德)andMing-WuZOU(邹明武)(EarthquakeResearchInstitu...
简介:SongkeWellNo.2,oneofthemainpartofthescientificdrillingprojectinSongliaoBasin,whichwasdrilled7018mandacquiredthepartofcorescontinuouslyfromtheLowCretaceoustotheCarboniferousandthePermianfromthe2843mdeep,canbeconsideredasthedeepestcontinentaldrillingprojectinAsia.Aimingatthefeaturesoflongerwellsections,largerdiametersandmultiplespud-insforcoringofSongkeWellNo.2,thisprojectbrokethroughthe"coringinsmalldiameterandreaminginlargediameter"spud-indrilling-completionprocedureswhicharealwaysusedinlarge-diameter-wellcoringforcontinentalscientificdrillingprojectsindomesticandoverseasandthedrillingmethodofshort-singlecylinderroundtripfootage.Atthesametime,"coringinthesamediameterandcompletingdrillingatonesinglediameter"wasachievedatallφ311mmandφ216mmcoringsectionsofmorethanonethousandmeterslong,high-efficientoperationwith"drillinglongfootagewithdrilltoolscombinedinmulticylinders"wasachievedatdeepcoringsection.Fourworlddrillingrecordswerecreatedwhichincludemorethanathousandmeterscontinuouscoringatφ311mm,andthefootageperroundtripfootageatφ311mm,φ216mmandφ152mmisallmorethan30m,allofthesebreakthroughsreducedatleast300daysforthisproject;moreover,consideringthecharacteristicsofformationsthatthegeothermalgradientishighinthedrilledsectionsandtheinside-welltemperatureisover240℃afterdrillingcompletion,aformate-polymerwater-basedmudsystemwasdevelopedbycompoundingattapulgiteandsodiumbentoniteandbyaddingindependentlydevelopedhigh-temperaturestabilizer,whichcanprovidecriticaltechnicalsupportforsuccessfulwellcompletionat7018minthesuper-high-temperatureenvironmentItisthefirsttimethatthewater-basedmudisoperatedattheworkingtemperaturehigherthan240℃inChina;Besides,consideringthehigh-qualityrequirementoncoresimposedbytheproject,themethod"mechanicalcor
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简介:摘要:水平井裂隙断层发育的水平段堵漏不同于其它井漏堵漏,根据漏失情况选择堵漏方式是关键,堵漏材料粒径选择是重点,封堵水平段裂隙断层时,堵漏材料必须能进入漏层且成功架桥封堵漏层,在保护储层的前提下,如何有效快速低成本的堵漏,是泾河2井区水平井钻井面临的主要问题,主要的堵漏方式有随钻堵漏、静止堵漏和高酸溶快速滤失堵漏。