摘要
Deepwatersedimentsarepronetolosscirculationindrillingduetoalowoverburdengradient.Howtopredictthemagnitudeofleak-offpressuremoreaccuratelyisanimportantissueintheprotectionofdrillingsafetyandthereductionofdrillingcostindeepwater.Startingfromthemechanicalpropertiesofashallowformationandbasedonthebasictheoryofrock-soilmechanics,thestressdistributionaroundaboreholewasanalyzed.Itwasfoundthattherockorsoilonaboreholeisintheplasticyieldstatebeforetheeffectivetensilestressisgenerated,andtheeffectivetangentialandverticalstressesincreaseasthedrillingfluiddensityincreases;thus,tensilefailurewillnotoccurontheboreholewall.Basedontheresultsofstresscalculation,twomechanismsandleak-offpressurepredictionmodelsforshallowsedimentsindeepwaterdrillingwereputforward,andthecalculatedvaluesofthesemodelswerecomparedwiththemeasuredvalueofshallowleak-offpressureinactualdrilling.TheresultsshowthattheMHPS(minimumhorizontalprinciplestress)modelandtheFIF(fracturinginformation)modelcanpredictthelowerandupperlimitsofleak-offpressure.ThePLC(permeablelostcirculation)modelcancomprehensivelyanalyzethefactorsinfluencingpermeableleakageandprovideatheoreticalbasisforleak-offpreventionandpluggingindeepwaterdrilling.
出版日期
2018年01月11日(中国期刊网平台首次上网日期,不代表论文的发表时间)