Limits on value recently provided by source of oil? That’s acceptable (4,4)
I believe the answer is:
very well
'that's acceptable' is the definition.
('very well' can mean you accept something)
'limits on value recently provided by source of oil?' is the wordplay.
I cannot quite see how this works, but
'source' could be 'well' (well is a kind of source) and 'well' is located in the answer.
The remaining letters 'very' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
(Other definitions for very well that I've seen before include "A1" , "compliant remark" , "Fit as a fiddle" , "I guess so" , "fine" .)