Making products from oil — some pretty rich, possibly (14)

I believe the answer is:

petrochemistry

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'making products from oil' is the definition.
I can't judge whether this definition defines the answer.

'some pretty rich possibly' is the wordplay.
'possibly' indicates anagramming the letters.
'some'+'pretty'+'rich'='someprettyrich'
'someprettyrich' with letters rearranged gives 'PETROCHEMISTRY'.

Can you help me to learn more?

(Other definitions for petrochemistry that I've seen before include "Study of the rocky" , "testing for oils" .)

I've seen this clue in The Times.

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