Russia's top oil producer Rosneft has turned to UK-certified lawyers in its fight against Ukraine-related Western sanctions which have hit the company's output and prospects for its push to tap Arctic riches.

This year's fall in energy prices is hastening the decline of big oil, as the seven Western majors sell-off assets, cut investment, return money to shareholders and shrink in size, leaving ever more output to small producers and state firms.

Canada scored a victory Tuesday when the European Union ditched plans to label oil derived from oil sands as dirtier than other forms of crude, removing a major potential obstacle to exporting the controversial fuel to Europe.

Lawyers for BP have called for a retrial or a revised judgment after spotting what they believe to be a legal mistake in the court ruling last month that the company acted with gross negligence in the 2010 Deepwater Horizon disaster.

In the wake of an energy overhaul that ends Mexico's state oil monopoly, a new exploration and production company was born with the name Sierra Oil & Gas, which Chief Executive Ivan Sandrea says already has a wealth of global expertise.

Shares in Norwegian Energy Company ASA (NOR. OS) plunged over 70% Wednesday and the oil firms chairman resigned after it warned that it could face problems in meeting its financial commitments.

Mexico is “like a sweet shop in the oil business”, according to one executive, and international energy companies are eyeing the goodies it offers as they wait for technical and fiscal details to work out how much they can splurge.

Some analysts and investors worry that oil companies will not spend enough either to sustain growth in their core businesses, or to open options in alternative energy sources for a world in which oil and gas consumption is constrained by climate policy or high prices.

BP ’s attempts to reclaim what it describes as excessive compensation payments for the 2010 Deepwater Horizon disaster have been rejected by a US court, in a further setback to the company’s hopes of limiting the cost of the accident.

By allowing international companies such as Exxon, Royal Dutch Shell, Halliburton, and Schlumberger to carry on their pumping, the White House and its European allies assured stability in global oil markets and in the prices consumers pay for gasoline.