Source for those asking: http://www.nytimes.com/2016/12/12/world/europe/rex-tillersons-company-exxon-has-billions-at-stake-over-russia-sanctions.html After the Russian incursion in 2014, the United States prohibited the transfer of advanced offshore and shale oil technology to Russia. The American government announced on Sept. 12 that year that Exxon was to halt all offshore drilling assistance to Rosneft, the Russian state oil company, by Sept. 26. But Exxon Mobil’s high-tech rig was already drilling in the Kara Sea, in an unfinished $700 million project that had yet to find oil. It would be worthless if not completed. Russian executives then told Exxon Mobil that Russia’s security services would fly in a Russian crew — in essence seize the rig — if Exxon Mobil complied with the American law and left without completing the well, according to an oil company executive who had visited the rig in the Arctic. Exxon relayed the threat to the American government, and the Treasury Department capitulated, granting an extension that stretched the window to work until Oct. 10. In a statement in 2014, the Russian state oil company denied conveying such a threat to Mr. Tillerson’s company. With the extension in hand, Exxon Mobil discovered a major field with about 750 million barrels of new oil for Russia a few weeks later. Igor I. Sechin, the chief executive of the Russian state oil company, called the newly discovered oil field Pobeda — Russian for victory. It is one of the Arctic developments that Exxon Mobil has rights to work on should the sanctions be lifted.