As you're probably already aware, petrol and diesel doesn't just appear at your local gas station. Many steps take place before you grab hold of the fuel pump. The first of those steps is taken on by upstream oil companies - these guys poke their straws in the ground all over the globe, sucking up crude oil and/or natural gas from underground or underwater locations.
Given how expansive this industry is, this Spark lists upstream companies boasting market capitalizations greater than $5bn. We have excluded integrated oil companies (organizations covering every segment of the industry - upstream, midstream, and downstream), and instead have included stocks that have their value pinned to exclusively oil extraction. However, just because it fuels your car doesn't mean it'll fuel your portfolio. This isn't advice - always remember to DYOR.