Saudi Aramco - ARAMCO AB
There’s already a request for the same stock here with 15 votes. I doubt it will ever be offered on FT, anyway.
Alternative routes could be buying ETFs or Investment trusts offering some exposure, moving to Saudi Arabia, and using CFDs. If your net worth is $30M or more, you could try the high net worth investor route. There could be other routes I’m not aware of (yet).