Key Players SchlumbergerHalliburtonTenaris(Techint)VallourecPAOTMK(TrubnayaMetallurgicheskayaKompaniyaOAO)WeatherfordInternationalNOVInc.(NationalOilwellVarcoInc.)ForumEnergyTechnologiesTricanWellServiceInnovexDownholeSolutionsNeOzEnergy