Run, run like the wind!!! Unless you can get a specialist in with a degreasing agent that wont wreck the couch,(you could possibly try the clothes pre-wash sprays with degreasing agent in them, I think napisan have a product out at the moment) otherwise, it was nice knowing you!
I once did the same thing on my mothers timber outdoor table thinking that it would be fine as wasn't oil good for timber?? Unfortunately it stained the table a different colour and it had to be stripped and repolished. I was not my mothers favourite daughter for a very long time, that was about 12 years ago and she still brings it up whenever she uses the table!!