With the update, even if you don’t have the DLC, fluids have been rebalanced. You just have to place a pump every 200-250 tiles and everything flows.

For oil specifically, you don’t need anything but petroleum liquid until what used to be late game. So just build a few (like a dozen) refineries and make sure that there’s actually oil coming in.

Once you actually need lubricant, and light oil, set up chemical plants to turn heavy oil into lube and light oil, and light oil into petroleum gas. It won’t be fast, but it won’t clog and it will produce what you need, slowly.

I consider myself a Factorio apprentice, as I have yet to actually set up a proper train system. I’m slowly learning circuit logic, but can get to Gelba without getting stuck.

Don’t stress optimization, brute force works as well.