When Saudi Aramco speaks, energy investors ought to listen.

With a quarter of the world's proven reserves of crude, Saudi Arabia's national oil company simply dwarfs the likes of ExxonMobil (NYSE:XOM) and PetroChina (NYSE:PTR). At least one analyst pegs Aramco's current daily take at $1 billion in revenue. The company's recent announcement that it seeks to lift its refining capacity by roughly three quarters in the next five years was big (and under-reported) news -- to this Fool, anyway.

Of course, if you keep an eye on Aramco, you know that it's been cutting deals faster than cards in the hands of a casino croupier. From ConocoPhillips (NYSE:COP) to Dow Chemical (NYSE:DOW), just about everybody who's anybody has a joint venture with these guys. Judging by Aramco's $70 billion allocation for new refining and petrochemical ventures, there are plenty more project announcements to come.

Who are the potential winners and losers here? A raft of new refineries could do wonders for contractors like Foster Wheeler (NASDAQ:FWLT), a company that's snagged Aramco work in the past. Equipment suppliers like Graham (AMEX:GHM), a vacuum system virtuoso, are also well positioned to profit.

I don't foresee any companies suffering terribly from this refinery build-out, but consider that many of Aramco's projects are focused on developing Saudi refining capacity. On the margin, I expect that would depress oil tanker demand when the supply comes on a few years out, but such a minor pinch wouldn't keep me up at night if I were a Frontline (NYSE:FRO) investor.

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