In this task, you are given a paragraph, and your job is to generate comma-separated entities present in the given paragraph. Generate entities from a given passage in such a way that (i) they are present in the paragraph, (ii) they are non-duplicate, (iii) they underwent a state change during the process. Avoid creating entities that (i) aren't present in the process paragraph and (ii) aren't significant.

A rig drills into the earth where oil is present. A pipe is placed in the hole. A pump is added to the pipe. Oil is pumped out. Oil is placed in barrels. Barrels are loaded on trucks. Trucks go to a refinery. Crude oil is refined to motor oil. Motor oil is bottle. Shipped to gas stations.
oil ; crude oil ,motor oil