In order to remove the fuel door, you must depress clips inside the wheel well.
In order to gain sufficent clearance, you may have to lift the right rear of the car about 6" to get your arm up inside the wheel well. After that, pull back the plastic inner fender liner. You may need a small screwdriver to pry the liner inward to initially get your fingers under the liner. Shove your arm up inside and feel around for the clips. From the front, looking at the door's chrome face, the clips are at the 11:30, 1:30, 5:00, and 7:00 o'clock positions. Depress the clips and pull and wiggle the fuel door with the door open. (Grabbing the open door gives you the needed leverage to wiggle things around). You'll feel them let go one at a time. Then remove the gas cap and pull the door and rubber grommet assembly off the gas filler tube. The gas cap retaining lanyard simply pops off with a screwdriver.