The main Saudi concern is to protect market share.

Saudi Arabia, the world’s largest oil exporter, deepened the discount at which it sells crude to Asia and the U.S., underscoring for some market watchers the kingdom’s commitment to defending its market share amid the recent rout in oil prices.

After OPEC’s announcement last week that it would not be cutting production, oil prices fell dramatically.

Russia did not ask OPEC for production cuts.

After the failure of its risky exploration strategy this year, Norwegian oil firm Statoil is cutting costs as fast and deep as it can to preserve cash for dividends

Gulf stock markets plunged on Sunday after OPEC's decision to keep crude output unchanged sent oil prices tumbling at the end of last week.

With a sustained price drop to $60 a barrel, North American shale drilling would be especially challenged in emerging fields such as some in Ohio and Louisiana, where costs are at the highest early in development, according to Citigroup and ITG.

Saudi Arabia and its OPEC allies’ firm stand against cutting crude output to slow the plunge in oil prices has set the energy world on a painful course that will leave the weakest behind, from governments to U.S. wildcatters.

Opec threw down the gauntlet to US shale oil producers by deciding not to cut its production, in a move that sent the oil price tumbling by more than 8 per cent to a four-year low.

Oil anchors world financial markets, and Opec has just decided to raise its anchor. The consequences could be profound, and go far beyond the power game between the traditional oil producers in the Middle East and the new generation of shale producers in North America.