The union, assuming it proceeds as planned, will give the company about one-fourth of the subsea market and propel it to the top tier of oilfield services providers by revenue. The announcement came just weeks after Schlumberger finalised a merger with Cameron, its joint venture partner in OneSubsea — and, it should be noted, shortly after the proposed marriage of Halliburton and Baker Hughes, the second and third-largest oilfield service companies, was scotched by the US Department of Justice.