Soldiers ordered to surround oil platform (7)
I believe the answer is:
brigade
'soldiers' is the definition.
(I've seen this before)
'ordered to surround oil platform' is the wordplay.
'ordered' becomes 'bade' (past tense of 'bid' as in to order).
'to surround' means one lot of letters goes inside another.
'oil platform' becomes 'rig' (I've seen this before).
'bade' enclosing 'rig' is 'BRIGADE'.
(Other definitions for brigade that I've seen before include "Army unit" , "Body of troops" , "Abridge (anag)" , "Army grouping" , "Military group" .)