How can I repair heavy hardwood scraping?
Without a picture it is a little hard to say.  Depending on the depth you may need to do one or both.

If the depth is shallow simply sand and refinish the spot (it will not look like new and particularly in certain light you will definitely always be able to see the spot).  

If the scratches/gouges are deeper you will have to sand, fill, sand, then refinish and again, you will be able to tell its a patch job.  edit:  if the wood is stained you may also need to stain the spot prior to finishing as well.

Make sure you match the sheen on the finish.  (Satin/Semi-Gloss/Gloss)

And use furniture pads next time!!! :)