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.

Global oil and gas exploration projects worth more than $150 billion are likely to be put on hold next year as plunging oil prices render them uneconomic, data shows, potentially curbing supplies by the end of the decade.

Oil prices slid to the lowest point in more than five years Friday as worries about a global glut of oil continued to weigh on the market.

The recent sharp falls in the oil price require further adjustments to asset values around the world. Oil was in most people’s forecasts and commentaries at about $110 a barrel earlier this year, but is now selling for under $70.

Sir Ian Wood, the Aberdeen-based billionaire and energy industry veteran, has given warning that tumbling oil prices will have a “horrible effect” on North Sea prospects.

A sharp drop in oil prices since the summer is creating a heap of trouble for Norway.

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

Schlumberger , the world’s largest oil services group, is cutting back its fleet for offshore geological surveys and taking an $800m writedown on the value of its ships, in the first significant cutback in the industry following the recent fall in crude prices.

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