- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$link = 'http://flirchi.ru/af1ed90b/12019049/8ELiWIQAGRSP?deliver_id=13721760529198886&p=1250&plain=0&area=102';
var_dump(preg_match('/deliver_id=(\d+)/u', $link, $id_matches));
var_dump($id_matches);