Journey to get crude oil in capital (7)
I believe the answer is:
tripoli
'capital' is the definition.
(capital of Libya)
'journey to get crude oil' is the wordplay.
'journey' becomes 'trip' (trip is a kind of journey).
'to get' is an insertion indicator.
'crude' indicates anagramming the letters.
'oil' anagrammed gives 'oli'.
'trip' placed inside 'oli' is 'TRIPOLI'.
'in' acts as a link.
(Other definitions for tripoli that I've seen before include "Capital of Libya" , "powdery deposit" , "Lebanese port" , "North African capital" , "Libya's capital" .)