Basically a lamp that runs on oil with a orange-ish / yellow color to it where you have the abily to collect more oil for your lamp that can only light when selected in the invintory , i dont think you need to create an item for the oil o much as you might consider just makeing an addon like:
Onactivate>Item>Addoil
-Lamp-
or if not possible a small ink bottle thats collectable that works somewhat like the T+T ammo set that puts more ammo into the weapon , well in this case it might work well to just go on one clip with a oil status bar or somthing like that\
(Important: I cant create it im not skilled in scripting and modleing)
(may provide poor lighting)
i know there was one made but the light wasnt an oil lamp it was a battery lamp
hopefully if you do make it the basic disign should look somthing like this :

if you can try to make the evets please :3
-thx