Schlumberger Ltd. SLB -1.40 % on Wednesday backed out of a $1.7 billion deal for a stake in Russia’s largest onshore drilling firm after Moscow didn’t approve the deal by a deadline imposed by the Western oil-services giant. The collapse of the deal highlights the deteriorating relations between Russia and the West amid sanctions over Ukraine. It comes after Schlumberger warned last week that it wouldn’t extend the latest several deadlines for Russian antimonopoly officials to approve the offer. Schlumberger didn’t respond to messages seeking comment. Last week, Schlumberger said it would instead focus on other merger-and-acquisition opportunities. The transaction was proposed in January , accepted by EDC and originally expected to close by the end of March. Then it apparently got bogged down over concerns in Moscow that EDC’s activities could be affected by Western sanctions against Russia. Russia’s Federal Antimonopoly Service, which was reviewing the deal, […]