The upstream, oil field services, midstream, and downstream businesses during the year collectively saw just 379 M&A deals take place, down from the 709 that occurred in 2014, and 409 and 389 that respectively took place in 2008 and 2009 amid the Great Recession. Total value in 2015 was $286.23 billion, down from $353.97 billion in 2014.

European stocks deepened a monthly rout as disappointing earnings reports reignited investor concern about global growth prospects and oil prices resumed their downward trend.

Last month, David Rubenstein, a founder of private-equity firm Carlyle Group, said he anticipates “maybe the greatest energy investing opportunities we’ve ever seen.” Marc Lasry, founder of hedge fund Avenue Capital, has described energy as a “once-in-a-lifetime opportunity.”

Eni has already developed phases 4 and 5 of the South Pars gas field as well as two phases of Darkhovin oilfield. It has shown interest in developing Iran’s North Pars gas field and also the third phase of Darkhovin oilfield.

Companies like BP, which said Tuesday it is cutting 4,000 jobs, are slimming down to cope with the slump in oil, whose price has plummeted to its lowest level in 12 years and is not expected to recover significantly for months, possibly years. California-based Chevron said last fall that it would eliminate 7,000 jobs, while rival Shell announced 6,500 layoffs.

“Companies have to be prudent in the face of what’s happening,” says Daniel Yergin, vice-chairman of consultancy IHS. “It’s a wrenching period for the industry.”

Iran needs $20bn to develop the remaining phases of the South Pars gas field, energy minister Bijan Namdar Zanganeh said

Oil companies including Royal Dutch Shell and Chevron have already slashed tens of thousands jobs globally to deal with a near 75 percent drop in oil prices since June 2014 that has seen earnings collapse.

Crude's collapse from $100 a barrel since mid-2014 has already pummeled Russia, which relies on energy for about half its budget revenues and 40 percent of its exports. The latest slide compounds the problems facing President Vladimir Putin ahead of elections in 2018.

"We are certain the Chinese economy will grow only slowly and that the yuan will depreciate in 2016," said a senior trader with a Shanghai-based fund. "The biggest uncertainty we have is how much the yuan will depreciate, which could revalue metals in China and affect our bets."

The IPO proposal is consistent with the broader direction of economic reform in the kingdom, including state asset sales and market deregulation, Aramco said. Bringing in investors would also strengthen the company’s focus on long-term growth and the prudent management of its reserves, according to the statement.

Even if E&P clients are able to negotiate more favorable terms for their debt, the industry’s overextended balance sheets will put a cap on activity — even if oil prices rise. On the producer side, companies will most likely de-lever before they drill should some extra cash come in the door. For OFS, building all the new equipment such as walking rigs and big frac spreads to meet strong client demand has some players in this sector significantly over-levered.

More than $60 billion in unsolicited corporate takeover bids during 2015 were rejected, causing deal value to drop to a 10-year low. Aside from the Shell-BG deal, there were no corporate takeovers exceeding $5 billion. Fewer than 10 asset deals valued at greater than $1 billion occurred, following more than 30 annually during each of the previous 2 years.

Dow e-minis were down 380 points, or 2.26 percent, with 99,258 contracts changing hands at 8:13 a.m. ET (1313 GMT). S&P 500 e-minis were down 45 points, or 2.27 percent, with 578,860 contracts traded. Nasdaq 100 e-minis were down 130.25 points, or 2.93 percent, on volume of 108,831 contracts.

West Texas Intermediate crude for February delivery declined to $36.58 a barrel on the New York Mercantile Exchange, after falling 0.8 percent Monday. U.S. crude inventories are forecast to keep supplies more than 130 million barrels above the five-year seasonal average, according to a Bloomberg survey before government data Wednesday.