oil to the surface Crude Oil Value Chain Transportation Gathering transporting pipelines, tankers, trucks MIDSTREAM Natural Gas Value Chain Gathering & Processing Fractionation MIDSTREAM Refining Fractionation of crude oil into petroleum products PowerPoint Presentation The oil and gas value chain starts with discovering fields and ends with providing products to end consumers. The different stages are exploration, production, storage and shipping, refining and marketing. Voice-over: - Oil and gas are generated from a source rock, organic matter buried in the depths of the earth. Oil and Gas Value Chain Seminar ppt. Ashu Admin 01 July 2017. What are Crude Oil and Natural Gas? Crude oil is is mixture of more than 500 organic chemicals, predominantly hydrocarbons that comes from reservoirs below the earth's surface. It is called crude oil because it must be processed or "refined" into useable products like gasoline.