Hey guys.. New question

I mostly wear a goatee. Shaved it off for a couple of years as I taught myself SR shaving, but really now it's back and SRs help me a lot maintain its shape and I still enjoy wet shaving the rest of my face.

Anyway.. What's the difference between shaving oil and beard oil? Are they similar or interchangeable?

I ask because I would like to start oiling my goatee and wanted to figure if I have to purchase beard oil or is my shaving oil sufficient?

Thanks in advance.