LONDON, Aug 5 (Reuters) - North Sea Brent crude
differentials weakened on Wednesday, although they remained at a
premium to dated Brent supported by tighter supply.
Supply of benchmark grades is due to fall in September from
an already low August figure.
* No deals.
* Brent: BP offered an Aug. 17-19 cargo at dated Brent minus
50 cents, down more than 10 cents from Tuesday's assessment.
* There were no indications on any other grades.
(Reporting by Alex Lawler. Editing by Jane Merriman)