You've struck oil in Frostpunk 2, but it's not going to do you much good out in the frozen frostland. You'll need to extract the oil (also known as black gold and Texas tea in some parts) and then transfer it to your city. It's not a complicated process but the tool that lets you transfer resources between your colony and your city can be a little hard to spot when there's so many other icons and notifications and UI elements on your screen...
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Frostpunk 2: How to transfer oil and other resources from your colony to your city
Source: PC Gamer (opens in a new tab)