磨损套管应力集中对腐蚀速率的影响

102249、。。。。TE273A1673-5285201204-0005-05!!!!!!!!!!!!!!*[e-mail]。EffectofworncasingstressconcentrationonitscorrosionrateLIUHuaiLiangGAODeliKeyLaboratoryofMinistryofEducationPetroleumUniversityofChinaBeijing102249ChinaAbstract:Withthehighsourgas,casingstringswillbeseverelycorrodedbyH2SandCO2,whichcanreducethecasingstrengthandshortenthecasinglifespan.Inthemeantime,thecasingstringwillbeworninevitablyinthedrillingprocesswhichwillnotonlylowerthecasingstrengthandacceleratethecorrosionrate,butalsoevenleadtocasingfailureinad－vance.Theauthorfirstgivesthemethodtocomputeweardepthofthecasingandderivesthestressconcentrationindexofawearcasing;thenusestheelectrochemistryknowledgetode－rivetheformulaoftheimpactofstressconcentrationtocorrosionrate.Attheend,wetakeanexampletoanalyzetheformulaandfindthatstressconcentrationhasagreateffectonthecorrosionrate,soitisquitenecessaryforustotakesomeeffectivemeasurestopreventcas－ingwear.Keywords:sourwellscasingwearstressconcentrationcorrosionratePETROCHEMICALINDUSTRYAPPLICATION31420124Vol.31No.4Apr.2012。Fierro.G[1]K.Masamura[2]H2S、CO2。2003[3]、[4]、[5]、[6]。、、。。。1。。1.1。[7]V=WF×Φ×SD1WF=μ/εWFμεSD=πDtj·60·N·t·fDtjmmNppmthf=Ltj/LdpLtjmmLdpmm。,。。。。1.2[8]1。1x2+y-k2=r22x2+y2=R23x1x2A=x1x2乙r2-x2姨+k-R2-x2姨dx4w=t+R-r-kk、。22PiFh[9]。Fh=乙riri+wPi+σθdr511Fh=Piw+PiRi2Ro2-Ri2w+PiRi2Ro2Ro2-Ri2wRiRi+w6Δσh=Fht-w720123162、3M=Δσht-wRo-t-w/2-FhRi+w/2=Fht/28σ=±Mr/IIm4Δσhm=±1.95Fh2R-Ro-Ri-wt-w2RRi+wRo9α=0.651-w/t。Δσhm=±1.95Fh2R-Ro-Ri-wt-w2RRi+wRo10、σhw=PiRi2Ro2-Ri2+PiRi2Ro2Ro2-Ri21R2+Fht-w±1.95Fh2R-Ro-Ri-wt-w2RRi+wRo11。乙Ri+wRi+tσhwdr=K乙Ri+wRi+tσdr12σ=PiRi2Ro2-Ri2+PiRi2Ro2Ro2-Ri21R23-。。[10]、。。、、。:i=ioexpΔPVRT13:v=voexpΔPVRT1414:v=voexpKΔPVRT15vomm/yK=σhw/σR＝8.314Jmol-1K-1V∪∪∪47cm3/molTKΔPMPa。4P110244.48×11.99mm3000m20MPa150℃。(12)15。4。41。1、5615。60%。60%。。660%。。。[11]、、/mm/v·vo-10.7621.146291.046671.2701.308861.053471.7781.523821.062522.2861.803251.074402.7942.162401.089863.3022.620731.109923.8103.203401.135964.3183.942951.169894.8264.882311.214455.3346.078621.273665.8427.609041.353646.3509.579341.464056.85812.137001.620917.36615.491711.852417.87419.948002.211838.38225.959172.809588.89034.218813.902919.39845.821996.193299.90662.5596912.0556725201231820。2%8%。。、。。。。。5160%60%。2、、。1FierroGIngoGMManclaFi.XPS2investigationonthecorrosionbehaviorof13Cr-martensticstainlesssteelinCO2-H2S-Cl2environmentJ.Corrosion198910:814.2MasamuraKHashizumeSSakaiJ.PolarizationbehaviorofhighalloyinCO2environmentasaffectedbychloridesandsulfidesJ.Corrosion9876:359.3.H2S/CO2N80J.200314470-75.4.CO2/H2SD.2005.5.CO2H2SJ.200526455-59.6.CO2/H2SJ.200314712-19.7RussellWhallAnimportantaspectofcasingwearA.SPE9430020052-3.8.J.20062765-7.9WuJZhangMG.CasingburststrengthaftercasingwearA.SPEOklahoma20056-9.10M..M.19895-8.11.J.20071865.4.J.2008342372-74.5.J.19921317-14.6.J.200514442-44.7.J.198998267-271.8.J.2005251191-93.8!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!425