The typical oil pan is not under pressure, and is not a structural part. It is just a "bucket" sitting under the engine
that the oil falls into, and gets sucked out of. So you aren't looking at a heavy-duty repair.
You should be able to take a brownie tin, sheet metal sign, piece of roofing tin, couple of flattened out tin cans, etc. and hammer/clip out a patch that covers the entire bottom of the pan, or the bottom and sides if need be. The only criteria is that if you glue it in place, the "glue" has to be able to resist hot oil for long periods, so it should be "oil proof" or "fuel proof". While you could put the patch on the outside of the pan, I'd recommend dropping the pan (will need a new gasket) and cleaning
out any rust and flakes that are in it, the applying the patch from the inside.
JBWeld and other epoxies fit that bill perfectly. Silicone might not hold under constant exposure to oil. A gasketing material that is rated for immersion in hot oil would be ok, or you could probably get a plumbing
torch and just solder in the patch.
That's a job for a tinker--literally--but go find a real tinker these days.<G>