20 pumpjacks is unlikely to only produce enough for 1 or 2 refineries.
What is the yield of the oil field? (IIRC about 200% is able to produce enough for one refinery, so you would need 1600% for 8)
Are all pump jacks connected?
Do they produce without backing up?
For a long stretch of pipes, you ...

Could you post your save ? Maybe there something you overlooked.

I think it just comes down to really slow petrol production. Not enough crude is getting into the refineries. I have over 20 pumps and 8 refineries, but only one refinery is going at a somewhat decent rate. The others are clicking ...

no this means you can produce infinite plastic and/or sulfur without worrying about production stopping ever.

You then need to reseach refining II to gain access to the other fluid.

Once you have progressed a bit more into the game, you now need to do the balance of the outputs for the ...

In the period between refining I and refining II the refinery still wants a balance of all three materials in order to produce. The problem is that two of these do not exist because you haven't discovered them. This means you can produce a handful of sulfur or plastic before production stops, and it ...

This entire release is a mess. I hate it.