Dyukov, 38, is the former head of Sibur Holding. On November 16, Gazprom proposed his appointment, to replace Alexander Ryazanov as head of Gazprom Neft, formerly Sibneft.
The Russian gas monopoly said last Wednesday it had refused to extend Ryazanov's contract, and would relieve him of two posts as deputy chairman of Gazprom's Management Committee, and president of Gazprom Neft.
Ryazanov will remain on Sibur's board of directors.
Last week, Russia's leading business daily Kommersant quoted sources close to Gazprom and Gazprom Neft who put Ryazanov's dismissal down to disagreements with the gas giant's top management over the oil subsidiary's independence.
Ryazanov told the newspaper last Wednesday that he saw "no point in staying at Gazprom Neft."
"I was ready to head Gazprom Neft only if it really remained an independent company," he said.
Ryazanov's successor on Gazprom's Management Committee, Valery Golubev, served in the KGB between 1979 and 1991, and then in the mayor's office at the same time as President Vladimir Putin, the paper said.
Vremya Novostei, a popular daily, offered another explanation for Ryazanov's departure, saying the move comes as part of consolidation of the energy giant's personnel and financial assets in anticipation of inevitable conflicts within the presidential administration in the run-up to the presidential election of 2008.
The paper said Ryazanov did not belong to any of the influence groups, which could have been a factor in his resignation.
