I like how they say "may be larger than Cantarell".  Just like those envelopes in the mail that say "You may already be a winner"...

Unfortunately we don't have any details on this new field yet.  For all we know, they might privately be able to say that with 95% certainty that this new field is smaller, but it would still be technically accurate to say "may be larger than Cantarell".

It must be very difficult to assess the size of a resource three miles below sea level with any kind of accuracy.  Given the games played I'd say you're right to be skeptical.