Twisting the knife deeper, the US is still drilling extra wells. The latest Baker Hughes rig count rose by two to 452 last week. Frackers have sold forward their production with hedge contracts, guaranteeing future supply whatever now happens.

"They took advantage of the window for a few weeks when oil was higher and locked in hedges of around $52 for 2017, and $55 for 2018," said Mr Hansen.

Esther George, the head of the Kansas Federal Reserve, told an oil forum on Friday that the average price needed by shale drillers to make a profit has fallen from $79 to $53 over the last two years as technology matures. Many are making money at prices well below that.

She had a warning for those who expect a return to business as usual in world oil, predicting that a "large amount" of production would come on stream as soon as prices push through the mid-50s. "I do not see much room for price appreciation," she said.  

Markets have grown cynical about Opec rhetoric on cuts. Yet it is increasingly clear that Saudi Arabia has genuinely reversed course under the new energy minister, Khaled al-Falih, and this has changed the character of the Vienna meeting entirely.

The Kingdom can no longer afford to fight a grueling war of attrition to force rivals out of the market. While it has succeeded in killing off $200bn of investment in deep-water projects, Canadian tar sands, and other high-cost ventures, this has come at a very high price.

The Saudis have been burning through foreign exchange reserves at a rate of $10bn a month, and contrary to general belief their usable reserve buffer is relatively thin. They face an internal banking and liquidity squeeze, a construction crash, and have had to tap the global bond markets on a large scale to pay their bills.

"The Saudis are the ones that have suffered the biggest hit in revenue and face the most financial pain, and it has gone on a lot longer than they ever anticipated," said Mr Fyfe.

Austerity policies are biting in earnest, threatening the social contract of cradle-to-grave welfare that underpins the Wahhabi regime. Cuts in salaries, perks, and allowances have reduced take-home pay for lower level state employees by as much as 60pc in some cases.

Intelligence analysts say the Saudi-led war in Yemen is proving far more expensive than admitted, suggesting that the budget deficit is significantly higher than the official figure of 13pc of GDP. It recently emerged from Pentagon papers that the Saudis have lost 20 of their state-of-the-art Abrams tanks.

Helima Croft from RBC says the Saudis are now throwing their full diplomatic weight behind the search for a deal, though markets have not yet grasped the significance of this. If the Saudis want a deal, a deal is what will almost certainly happen.

Crucially, they need a much firmer oil price to have any chance of floating a 5pc share of state oil company Saudi Aramco for a very ambitious $100bn. The country is about to release secret details about the true extent of Saudi reserves, frozen at a constant 260bn barrels since the inception of the modern oil age - a patently absurd estimate.

David Fuller's view

Saudi Arabia’s Tadawul All Share Index has had a good bounce since retesting the January low last month.  If it were to push above 7000 and hold those gains beyond the very short term, it would suggest to me that someone or more likely some group of investors was anticipating higher prices for Brent Crude Oil than current supply/demand figures suggest. 

What might that be?  Some global economic recovery, which I do expect given reflationary efforts both occurring and pending, would increase demand.  However, with commodities supply is always the key variable, and there is no shortage of oil above ground or which could be produced quite easily, not least from the Permian Basin.    

We know that some form of OPEC plus Russia cutbacks are possible, or more likely a price freeze.  However, while that would keep Brent prices above $50 for the medium term, production limits are only honorary agreements and cannot be enforced. 

Nevertheless, every oil exporting country and every private oil company would benefit from a spike in the price of crude oil, even though I maintain that it would have little chance of holding beyond the short term.  A temporary, unofficial hold on the production of oil, from Saudi Arabia and Russia to the Permian Basin, could lift prices enough to enable some further hedging by producers in higher priced futures contracts. It could even help the Saudis with their 5% float of Saudi Aramco. 

I regard a spike in oil prices above $70 to $80 as only an outside chance, and no more than a temporary event, but it is just possible, given the renewed interest in commodity prices. 

Here is a PDF of AE-P's article.