drill rig vs drilling rig

drill rig and drilling rig both are nouns.

Word	Noun	Adjective	Verb	Adverb
drill rig	Yes	No	No	No
drilling rig	Yes	No	No	No

As nouns, drill rig and drilling rig are synonyms defined as:

Other synonyms of drill rig include oil rig, oilrig.

drill rig (noun)	drilling rig (noun)
rig used in drilling for oil or gas	rig used in drilling for oil or gas