Extraction

Plastics are petroleum based and so when people are drilling for oil, they aren't just doing it for fuel. To locate an oil field geologists use seismic pulses and study the nearby ground for seismic response. When they have located the whereabouts of the oil well the companies insert a drill into the earth. After that a steel pipe is put into the hole to provide structural integrity for the newly drilled well. Holes are then made in the base of the well to enable oil to pass into the bore. Finally a collection of valves called a "Christmas Tree" is fitted to the top, the valves regulating pressures and controlling flows. Here's a picture of a pump jack with the well below.

But this is a perfect scenario oil well. What if you have tar sands like Alberta? Then you have to dig massive pits in the earth, 40-60 meters deep. Then you load up huge dump trucks with oily sand. Then you take this sand and add it to a big mixing pot full of water and NaOH. The ratio of barrels of water to make on barrel of oil is 3water:1oil
The oil sands are leaving a large footprint on the earth in terms of environment. And then you always run the risk of another BP Oil Spill happening when you're shipping the oil to the refineries. This is not sustainable.