This is tough, as granite is porous.
After a lot of clear soap and then hot water rinsing a lot, then let it dry for a few days.
Then I’d try a pro-grade granite sealer on another section of the countertop that isn’t connected. It should make the top look darker. If it does, then consider doing that sealer up to edges of the oil stains, not on them.
Hi, this video should assist you
I don't have granite, but I have a marble island, so it should work similarly. The baking soda poultice works great on oil spots! Leave it on there for a few hours. Then rinse. Repeat if necessary. Once clean, go ahead and reseal your stone to protect it. It's just a wipe-on product.