Here we see a typical oil well and "nodding donkey" pumpjack rendered in LEGO form, ready to start pumping crude oil. (link to Wikipedia for more on pumpjacks, in case you don't know what they are.)
The oil well design was heavily modified in design and usage, as it was originally designed as the lower half of a water tower for steam trains!
The oil pumpjack features a crank as a play feature, (which could easily be motorized) though it doesn't actually pump anything. My video from Flickr showing it in motion is being stupid and won't embed, so here's a link to it instead.
Thoughts?
UPDATE 7/10/23: Model finished, real world photos added to main post!