OCTG casing yog ib qho ntawm cov txheej txheem tseem ceeb tshaj plaws hauv cov roj thiab cov qhov dej. Nws muab kev ruaj ntseg zoo, tiv thaiv kev sib tsoo, cais cov cheeb tsam sib txawv, thiab tiv thaiv cov dej hauv av. Qhov kev ua tau zoo ntawm casing nyob ntawm ntau yam ntawm cov khoom siv qib xaiv. OCTG casing qib yog tus qauv feem ntau raws li API 5CT, uas txhais cov tshuaj muaj pes tsawg leeg, cov khoom siv kho tshuab, kev kho cua sov, thiab cov txheej txheem kuaj. Txhua qib yog tsim los kom tau raws li qhov tshwj xeeb downhole siab, kub, thiab corrosion tej yam kev mob. Nkag siab txog qib sib txawv ntawm OCTG casing cov ntaub ntawv yuav tsum tau tshuaj xyuas cov kev faib tawm ntawm lub zog, kev pabcuam ib puag ncig tsim nyog, thiab cov yam ntxwv ntawm metallurgical.
API 5CT Casing Qib Classification
Lub zog-Raws li Qib Qib
API casing qib feem ntau raug xaiv los ntawm tsab ntawv ua raws li tus lej. Tus lej sawv cev rau qhov tsawg kawg nkaus tawm lub zog hauv ntau txhiab psi. Piv txwv li, J55 muaj qhov tsawg kawg nkaus lub zog ntawm 55,000 psi, thaum P110 muaj qhov tsawg kawg nkaus yield zog ntawm 110,000 psi. Qhov kev faib tawm no tso cai rau cov kws tshaj lij los ntsuas cov khoom thauj sai sai -cov kabmob muaj peev xwm ntawm cov khoom siv.
Cov qib qis zog yog siv nyob rau hauv qhov dej ntiav uas sab nrauv tsim siab thiab sab hauv cov khoom siab yog qhov nruab nrab. Raws li qhov tob nce ntxiv, lub casing yuav tsum tiv taus ntau dua kev sib tsoo thiab tawg siab, yuav tsum muaj qib siab zog. Txawm li cas los xij, kev ua kom muaj zog feem ntau txo cov ductility, yog li xaiv cov khoom siv yuav tsum sib npaug ntawm kev ua haujlwm thiab kev puas tsuaj.
Common API Casing Qib
Cov qib carbon steel feem ntau siv xws li H40, J55, K55, N80, L80, C90, T95, thiab P110. Cov qhab nia no suav nrog ntau lub zog ntawm qib siab thiab kev pabcuam ib puag ncig. Cov lus hauv qab no qhia txog cov khoom siv hluav taws xob ntawm cov neeg sawv cev cov qib casing.
| Qib | Yam tsawg kawg nkaus tawm lub zog (MPa) | Yam tsawg kawg Tensile Strength (MPa) | Daim ntawv thov |
|---|---|---|---|
| H40 | 276 | 414 | Qhov dej ntiav |
| J55 | 379 | 517 | Nto thiab nruab nrab casing |
| K55 | 379 | 655 | Zoo ib yam li J55, siab zog tensile |
| N80 | 552 | 689 | Qhov dej tob dua |
| P110 | 758 | 862 | Siab -qhov tob tob |
H40 thiab J55 feem ntau yog siv rau saum npoo casing cov hlua, qhov twg cov qauv kev txhawb nqa yog xav tau tab sis lub siab loads kuj tsawg. N80 thiab P110 yog ib txwm muaj nyob rau hauv kev tsim cov casing rau cov reservoirs ntxaum qhov kev sib tsoo thiab tawg tsis kam yog qhov tseem ceeb.
Corrosion{0}}Resistant thiab Sour Service Qib
Sour Service Requirements
Thaum lub qhov dej muaj hydrogen sulfide (H2S), cov khoom casing yuav tsum tiv thaiv sulfide kev nyuaj siab tawg. Txheem siab - lub zog carbon steel yuav ua rau nkig hauv qhov chaw qaub. Txhawm rau hais txog qhov no, API qhia cov qib hloov pauv xws li L80, C90, thiab T95, uas yog tsim los rau cov ntawv thov kev pabcuam qaub.
Cov qib no tswj cov qib hardness thiab tshuaj lom neeg muaj pes tsawg leeg los txhim kho kev tiv thaiv tawg nyob rau hauv corrosive tej yam kev mob. Cov txheej txheem kho cua sov xws li quenching thiab tempering yog ua tib zoo tswj xyuas kom tsim nyog microstructure thiab toughness.
L80 Variants thiab Alloyed Qib
L80 yog ib qho ntawm cov kev pabcuam qaub uas siv ntau tshaj plaws thiab muaj ntau yam sib txawv, suav nrog L80 Hom 1, L80 9Cr, thiab L80 13Cr. Cov ntsiab lus chromium nyob rau hauv 9Cr thiab 13Cr versions txhim khu kev tiv thaiv rau carbon dioxide corrosion, ua rau lawv haum rau CO2-nplua nuj qhov dej.
Cov lus hauv qab no sib piv cov kev sib txhuam corrosion-cov qib resistant casing thiab lawv cov yam ntxwv.
| Qib | Cov ntsiab lus alloy | Corrosion Resistance | Ib puag ncig ib puag ncig |
|---|---|---|---|
| L80 Qauv 1 | Cov pa roj carbon steel | Nruab nrab | Kev pabcuam me me |
| L80 9Cr | 9% Chromium | Txhim kho CO2 tsis kam | CO2-nplua nuj qhov dej |
| L80 13Cr | 13% Chromium | Siab CO2 tsis kam | Corrosive gas qhov dej |
| T95 | Tswj hardness carbon steel | Qab zib pab resistant | High H2S qhov dej |
| C90 | Tswj cov pa roj carbon steel | Kev pabcuam qaub | Intermediate H2S |
Qhov sib ntxiv ntawm chromium ho txhim khu kev tiv thaiv rau carbon dioxide corrosion tab sis nce nqi khoom. Yog li ntawd, cov qib alloy feem ntau raug xaiv thaum ib puag ncig ib puag ncig pom zoo rau kev nqis peev.
Mechanical Performance Considerations
Collapse thiab Burst Resistance
Cov qib casing raug xaiv tsis tau tsuas yog raws li lub zog tawm los, tab sis kuj nyob rau hauv lub cev qhuav dej thiab lub zog tawg. Collapse kuj tiv thaiv tawm tsam sab nraud tsim siab, thaum tawg tiv thaiv tiv thaiv sab hauv zoo siab. Qib siab zog feem ntau muab kev tiv thaiv zoo rau ob hom kev ua tsis tiav.
Cov kws tsim qauv tsim suav cov yam ntxwv ntawm kev nyab xeeb raws li qhov xav tau ntawm qhov kev poob qis, qhov kub thiab txias gradients, thiab cementing loads. Cov hlua casing feem ntau yog tsim los nrog ntau qib, siv cov ntaub ntawv muaj zog qis dua nyob rau sab sauv thiab cov ntaub ntawv muaj zog dua ntawm qhov tob dua.
Kub thiab Thermal Stress
High -kub qhov dej qhia txog kev sib tw ntxiv. Qhov kub siab tuaj yeem txo qhov muaj zog tawm los thiab ua rau muaj kev cuam tshuam rau creep deformation. Hauv cov xwm txheej zoo li no, cov khoom siv ntawm qhov kub thiab txias yuav tsum raug ntsuas ntau dua li tsuas yog tso siab rau ntawm chav tsev - qhov ntsuas kub.
Kev kho cua sov sib xws yog qhov tseem ceeb rau kev tswj xyuas cov khoom sib xws ntawm cov yeeb nkab ntev. Txhua qhov kev hloov pauv hauv microstructure tuaj yeem tsim cov ntsiab lus tsis muaj zog nyob rau hauv thermal cycling tej yam kev mob.
Kev Tswj Xyuas Zoo thiab Ntawv Pov Thawj
Cov qauv kuaj thiab tshuaj xyuas
API 5CT yuav tsum muaj kev ntsuam xyuas txhua yam, suav nrog kev sim tensile, kev sim flattening, ntsuas hydrostatic siab, thiab tsis yog - kev kuaj xyuas puas tsuaj. Kev ntsuas cuam tshuam tej zaum yuav tsum muaj nyob rau hauv qis - kev pabcuam kub kom ntseeg tau tias muaj zog txaus.
Txhua qhov sib koom ua ke yog traceable rau nws cov xov tooj cua sov thiab ntau lawm batch. Kev cim kom raug ua kom pom cov qib, qhov loj me, qhov hnyav, thiab cov ntsiab lus ntawm cov chaw tsim khoom. Qhov no traceability yog qhov tseem ceeb rau kev ruaj ntseg zoo nyob rau hauv siab -kev pheej hmoo drilling.
Kev sib txuas Compatibility
Ntxiv nrog rau cov khoom qib, kev ua haujlwm casing nyob ntawm kev sib txuas threaded. Cov kev sib txuas hwm zoo yuav xav tau rau siab -siab lossis roj- nruj daim ntawv thov. Cov qauv kev sib txuas yuav tsum sib haum nrog cov qib casing kom muaj kev ncaj ncees ntawm cov qauv.
Xaus
OCTG casing cov ntaub ntawv qib yog tsim los ua kom tau raws li ntau yam ntawm qhov chaw downhole, los ntawm qhov dej ntiav dej mus rau qhov tob, siab -siab, thiab corrosive reservoirs. Lub zog-raws li kev faib tawm xws li J55, N80, thiab P110 hais txog cov kev xav tau ntawm cov khoom siv kho tshuab, thaum cov qib tshwj xeeb xws li L80, C90, thiab T95 muab kev tiv thaiv zoo rau qhov chaw qaub.
Kev xaiv cov qib casing uas tsim nyog suav nrog kev ntsuas cov khoom muaj zog, kev sib tsoo tsis zoo, muaj peev xwm corrosion, qhov kub thiab txias, thiab kev ua raws li kev cai. Los ntawm kev ua raws cov khoom siv nrog cov xwm txheej zoo, cov neeg ua haujlwm tuaj yeem ua kom muaj kev ncaj ncees ntawm cov qauv, kev nyab xeeb ntawm kev ua haujlwm, thiab ntev - kev ntseeg siab ntawm cov roj thiab roj thiab cov dej num tshawb nrhiav.
