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Exhibit 21.1
 SUBSIDIARIES OF THE REGISTRANT
 State or Country ofName
    
    Incorporation1265840 Alberta Ltd.
    
    AlbertaAckerman International Holland B.V.
    
    NetherlandsAdvanced Wirecloth, Inc.
    
    LouisianaAmclyde UK Limited
    
    United KingdomBlack Max Argentina S.A.
    
    ArgentinaBowen Downhole LLC
    
    DelawareBowen Downhole, Inc.
    
    DelawareBrandt Energy Environmental, L.P.
    
    TexasBrandt Interests, Inc.
    
    DelawareBrandt Norge
    
    NorwayBrandt Oilfield Services (M) Sdn. Bhd.
    
    MalaysiaBrandt Servicios Petroleros S.A.
    
    PeruChurch Oil Tools, Inc.
    
    TexasCoil Services (North Sea) Limited
    
    United KingdomCorlac Equipment Corp
    
    BarbadosCTES, L.P.
    
    TexasDreco Acquisition Corporation
    
    AlbertaDreco DHT, Inc.
    
    DelawareDreco Eastern Europe Ltd.
    
    AlbertaDreco Energy Services Ltd.
    
    AlbertaDreco Europe Limited
    
    United KingdomDreco International Finance (Barbados) Ltd.
    
    BarbadosDreco International Holdings Ltd.
    
    AlbertaDreco Limited
    
    United KingdomDreco LLC
    
    DelawareDrexel Oilfield Services (Middle East) L.L.C.
    
    United Arab EmiratesElmar Far East Pty Ltd
    
    AustraliaElmar Services (Middle East) Limited
    
    United KingdomElmar Services Pty Ltd
    
    AustraliaEnvironmental Procedures Inc.
    
    DelawareFiber Glass Systems (Harbin) Co., Ltd.
    
    ChinaFiber Glass Systems Holdings, LLC
    
    DelawareFiber Glass Systems, L.P.
    
    TexasGriffith Downhole Products GmbH
    
    GermanyHarbin Star Fiberglass Ltd.
    
    ChinaHerramientas Varco, S.A. de C.V.
    
    MexicoHITEC AS
    
    NorwayHydralift Amclyde, Inc.
    
    DelawareHydralift AS
    
    NorwayHydralift BLM SA
    
    FranceHydralift France SAS
    
    FranceHydralift Holding UK Ltd.
    
    United KingdomHydralift UK Limited
    
    United KingdomHydra-Rig, Inc.
    
    DelawareInspecciones y Pruebas No Destructivs, S.A. de C.V.
    
    MexicoJV FIDMASH
    
    BelarusLanzhou LS-National Oilwell Petroleum Engineering Co. Ltd.
    
    ChinaLLTT, Ltd.
    
    Trinidad And TobagoLSI Asia Pacific Pte. Ltd.
    
    SingaporeM.S.D. de Venezuela, C.A.
    
    VenezuelaMJS Inspection Services Ltd.
    
    AlbertaMolde Produksjonssenter AS
    
    Norway




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State or Country ofName
    
    IncorporationMono Group
    
    United KingdomMono Group Pensions Trustees Limited
    
    United KingdomMono Pumps (Australia) Proprietary Limited
    
    AustraliaMono Pumps Ltd.
    
    United KingdomMono Pumps New Zealand Limited
    
    New ZealandNational Oilwell Algerie
    
    AlgeriaNational Oilwell de Mexico S.A. de C.V.
    
    MexicoNational Oilwell de Venezuela, C.A.
    
    VenezuelaNational Oilwell DHT, LP
    
    DelawareNational Oilwell do Brasil LTDA
    
    BrazilNational Oilwell France S.A.R.L.
    
    FranceNational Oilwell Middle East Company
    
    Nova ScotiaNational Oilwell Norway AS
    
    NorwayNational Oilwell Nova Scotia Company
    
    Nova ScotiaNational Oilwell Ontario, LLC
    
    DelawareNational Oilwell Services de Mexico, S.A. de C.V.
    
    MexicoNational Oilwell Sogne AS
    
    NorwayNational Oilwell Varco International Trading (Shanghai) Co., Ltd.
    
    ChinaNational Oilwell Varco Petroleum Equipment (Shanghai) Co., Ltd.
    
    ChinaNational Oilwell Varco UK Limited
    
    United KingdomNational Oilwell Varco, L.P.
    
    DelawareNational Oilwell-Netherlands B.V.
    
    NetherlandsNational Oilwell Poland S.p.z.o.o.
    
    PolandNational-Oilwell Canada Ltd.
    
    AlbertaNational-Oilwell Pte. Ltd.
    
    SingaporeNational-Oilwell Pty. Ltd.
    
    AustraliaNatoil LLC
    
    DelawareNatoil, Inc.
    
    DelawareNBJ Manufacturas de Venezuela C.A.
    
    VenezuelaNBJ Manufacturas Petroleras (Bolivia) S.A.
    
    BoliviaNOV (Caymans), Ltd.
    
    Cayman IslandsNOW (Barbados) SRL
    
    BarbadosNOW (China), Inc.
    
    MauritiusNOW Canada, L.P.
    
    AlbertaNOW Downhole Tools, Inc.
    
    DelawareNOW International Nova Scotia Company
    
    Nova ScotiaNOW International, Inc.
    
    DelawareNOW Nova Scotia Holdings, Inc.
    
    DelawareNOW Oilfield Services, Inc.
    
    DelawareNQL (Illinois) Inc.
    
    IllinoisNQL (US) Inc.
    
    DelawareNQL Energy Services US, Inc.
    
    TexasNQL Energy Services (Barbados) Ltd.
    
    BarbadosNQL Energy Services Canada Ltd.
    
    AlbertaNQL Energy Services Inc.
    
    AlbertaNQL Finance, L.L.C
    
    DelawareNQL Holland B.V.
    
    NetherlandsOilfield Techno Equipment Limited
    
    United KingdomP&T Servicios Petroleros, C.A.
    
    VenezuelaPesaka Inspection Services SDN.BHD.
    
    MalaysiaPrescott Drilling Motors, Inc.
    
    LouisianaPretempca Servicios de Mexico, S.A. de C.V.
    
    MexicoProcon Engineering Ltd.
    
    United KingdomPT National Oilwell Varco
    
    IndonesiaRemediation Management Services, L. C.
    
    TexasScreen Manufacturing Co. Ltd.
    
    Trinidad And TobagoServicios Tubulares TT, S.A. de C.V.
    
    MexicoServizi Ispettivi s.r.l.
    
    ItalyShaffer India Private Limited
    
    IndiaShanghai NOW-LS Engineering Consulting Co. Ltd.
    
    China




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State or Country ofName
    
    IncorporationSmart Screen Systems, Inc.
    
    MinnesotaSoil Recovery A/S
    
    DenmarkSTAR Sudamtex Tubulares S.A. (Joint Venture)
    
    VenezuelaTexas Oil Tools, Inc.
    
    NevadaThe Brandt Company de Argentina S.A.
    
    ArgentinaTS&M Supply
    
    AlbertaTS&M Supply  Ontario
    
    OntarioTS&M Technical Sales & Maintenance Company
    
    Nova ScotiaTube-Kote, Inc.
    
    TexasTubo-FGS, L.L.C.
    
    DelawareTuboscope & Co. LLC
    
    OmanTuboscope (Holding U.S.) Inc.
    
    DelawareTuboscope (Thailand) Ltd.
    
    ThailandTuboscope Brandt de Colombia
    
    ColombiaTuboscope Brandt de Venezuela C.A.
    
    VenezuelaTuboscope Canada
    
    AlbertaTuboscope Holdings Limited
    
    United KingdomTuboscope Holdings UK Ltd.
    
    United KingdomTuboscope Mexico, S.A. de C.V.
    
    MexicoTuboscope Norge AS
    
    NorwayTuboscope Pipeline Services Canada Inc.
    
    AlbertaTuboscope Pipeline Services Inc.
    
    TexasTuboscope Pipeline Services Limited
    
    United KingdomTuboscope Services, L.L.C.
    
    DelawareTuboscope Servicios de Bolivia S.A.
    
    BoliviaTuboscope Vetco (Deutschland) GmbH
    
    GermanyTuboscope Vetco (France) S.A.
    
    FranceTuboscope Vetco (Osterreich) GmbH
    
    AustriaTuboscope Vetco Canada Inc.
    
    AlbertaTuboscope Vetco Capital Limited
    
    United KingdomTuboscope Vetco de Argentina S.A.
    
    ArgentinaTuboscope Vetco do Brasil Equipamentos e Servicos Ltda.
    
    BrazilTuboscope Vetco Mexico, S.A. de C.V.
    
    MexicoTuboscope Vetco Moscow
    
    Russian FederationTuboscope Vetco Nigeria Limited
    
    NigeriaTulsa Equipment Manufacturing Company
    
    OklahomaTVI Holdings, L.L.C.
    
    DelawareV.O.F. ACE Downhole Tools and Services
    
    NetherlandsV/I Canada, Inc.
    
    AlbertaVarco (Beijing) Co. Ltd.
    
    ChinaVarco Al Mansoori Services Company LLC
    
    United Arab EmiratesVarco BJ BV
    
    NetherlandsVarco BJ FSC Inc
    
    BarbadosVarco Canada Limited
    
    AlbertaVarco CIS
    
    Russian FederationVarco do Brasil Ltda.
    
    BrazilVarco I/P, Inc.
    
    DelawareVarco International de Venezuela, C.A.
    
    VenezuelaVarco International do Brasil Equipamentos e Servicos Ltda.
    
    BrazilVarco International Inc. Pte. Ltd.
    
    SingaporeVarco International Pte. Ltd.
    
    SingaporeVarco Norge AS
    
    NorwayVarco Sara (India) Private Limited
    
    IndiaVarco Shearer Inc.
    
    AlbertaVarco U.S. Holdings, Inc.
    
    DelawareVarco UK Acquisitions Limited
    
    United KingdomVarco US Finance, Inc.
    
    DelawareVarco, L.P.
    
    DelawareVCR Panama Inc.
    
    PanamaVector Oil Tool Ltd.
    
    Alberta




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State or Country ofName
    
    IncorporationVenwell International Inc. (Trinidad Branch)
    
    TexasVersatech International Ltd.
    
    AlbertaVetco Coating GmbH
    
    GermanyVetco Enterprise AG
    
    SwitzerlandVetco Pipeline Services Ltd.
    
    AlbertaVetco Pipeline Services, Inc.
    
    TexasVetco Saudi Arabia Ltd.
    
    Saudi ArabiaVetco Services Sendirian Berhad
    
    Brunei DarussalamVetco Technology GmbH
    
    GermanyWellsite Gas Detection Inc.
    
    AlbertaWoolley, Inc.
    
    TexasXST Holdings, Inc.
    
    Texas