php截取字符串中间的字符串(设定开头和结尾)

例如：我们要获取：EE20181017143211468888

$result = '积分商城扣除积分 1订单号: EE20181017143211468888 OPENID: sns_wa_o_L7W5R4HWpw1kY5DXjzsdu9eCSc';
$bb = strpos($result,"订单号: ",0);
$cc = strpos($result," OPENID",0);
$dd =  substr($result,$bb+11,$cc-$bb-11);
var_dump($dd);