定向井井筒弯曲载荷半逆解法和等效应力的数值解答

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关键词：定向井井筒；Mises等效应力；非均匀地应力；三维力学模型；剪应力；应力分析；套管强度中图分类号：TE931.2 文献标志码：A 文章编号：1000-7393（2025）-04-0423-11

Abstract：Thedirectioalwellborsaresubjectedtoomplicated in-situtressssuchasinteal pressre，exteal pressureaia

force，shearingstressandbendingstres（caused bydogleg），whichoftenleadtodownholeproblems includingcasingfailure， colapse，andbadbreak.Atpresent，mostofthewellbore mechanicalmodelsestablishedinrelatedstudiesaretwo-dimesional paterns，ignoringtheifluenceofsearingstresswhichsultsiunderestimatigthequvalenttresofthewellbor.Itispape athre-dimensoalmechanicalmodelforectioalwellsistablshd，integatingtheloadsidingintealpeo uniformi-siusressialfore，saringresndbedingressOntebsisoftsodel，tealulatinfoulafois equivalentstrsofwelboreiserivd，andtheeffectsofsuchfctorsasnon-unifoi-siustress，searingstrssokelastic modulus，Poisson'atiotealprureduthhlboealetsrealedtialii are equal， the results show that the non-uniformity of the third axial in-situ stress increases by 18% ，the Mises equivalent stress of the casing increases by 36% ，and the equivalent stress increases remarkably with the increase of non-uniformity.When the three axial insitu stresses are totally different， the Mises equivalent stress of the casing increases by 38% for a 17% increase in non-uniformity. With same non-uniformity，the casing stress is larger，resulting in lessafe welbore. When the shearing stress of 7.3% of the peak normalin-situstress isappliedtothewelbore model，the Misesequivalentstresofthecasing，cementsheathandwellorerock increasesby284.79nd3.75timeespectively.Misesquivalentstrsofteasingisiverselyproportioaltoeelastic modulusandPoiss'satiooforeoleock.Tiseseachanestablshtheaccuratefailurecriteronfordirectionalwelloresction， thus，preventingorreducing the downholecomplications.Itcan also provideanew idea forsolving Misesequivalent stresof directional wellbore section under complicated in-situ stresses.

eywords：diretioalwelbore;Misesequivalenttres;non-unifin-siustress;thredimensioalmechanicalmoel;searing stress; stress analysis; casing strength

0 引言

定向井井筒具有大井斜、大位移等特点，使其承受内压、外压、轴向力及弯矩等复杂载荷作用，这不仅导致井壁稳定性难以保证，还常常引发井筒应力破坏。（剩余17670字）