Schlumberger and Smith Intl. merger, who’s next??

With energy demand rising, service companies are seeking to be more diversified and become the one-stop shop for many E&P companies facing more challenging and complex reserves.  Many of the big players are eager to acquire complimentary companies (and competitors) as we have seen with the Schlumberger & Smith International merger.  Who’s next?  And what does this mean for Halliburton?