Oil stocks are shares of companies involved in the production, transportation, refining, and servicing of crude oil and related petroleum products — including upstream explorers/producers, midstream pipeline and storage firms, downstream refiners and marketers, and oilfield service companies. The Upstream segment explores for and produces crude oil and natural gas. Read Our Latest Research Report on SLBPetroleo Brasileiro S.A.- Petrobras (PBR)Petróleo Brasileiro S.A. – Petrobras explores, produces, and sells oil and gas in Brazil and internationally. The Exploration and Production segment explores, develops, and produces crude oil, natural gas liquids, and natural gas primarily for supplies to the domestic refineries. The company's Oil and Gas segment explores for, develops, and produces oil and condensate, natural gas liquids (NGLs), and natural gas.