Whilst it is possible to make but nut butter without adding oil, I often use a little (a tablespoon or 2, just enough to get the right texture). You do need to blitz/scrape down several times. From memory quirky cooking has a good Peanut butter recipe you could try following that?
I also like making almond butter but avoid it because I tend to eat it too much. Lol. ABC butter is my fave (almonds, Brazils and cashews).