The firm announced yesterday that 22 major projects and 7 billion barrels of oil equivalent of commercial reserves have been delayed over the past six months.

These figures represent the additional pre-financial investment decision projects and volumes Wood Mackenzie estimates have been deferred due to lower oil prices which this week nudged just under $US30/barrel before hovering just above this morning.

This was reinforced by a survey of 225 companies for Barclays' annual E&P Spending Outlook, which revealed upstream oil and gas companies planned to cut their spending by 15% globally this year after a 23% drop in 2015.

This is just the second time spending dropped in consecutive years in the survey's 31-year history. The first "double-up" decline was way back in 1986-87.

Offshore spending is set to fall a further 20-25% as global oilers slash exploration budges and cut frontier programs.

"With only 15% of North America E&Ps having officially announced budgets and large-cap E&Ps only hedged on 13% of production, more than ever, oil prices will dictate spending in North America," Barclays said.

The survey showed international upstream spending would decline 11% in 2016 after a 17% fall in 2015, though spending by Russia and the former Soviet Union is expected to increase 3.6% in 2016 after a brutal 2015 in which E&P spending collectively declined 20%.

Middle East spending is projected to edge up 6% this year after dropping by the same amount last year.

Latin America's national oil companies are expected to cut spending by about 18% in 2016 after a similar rate of decline in 2015, as Brazil's Petrobras, Venzuela's Petroleos de Venezuela SA and Argentina's YPF struggle to generate enough cash to support upstream activity.

Wood Mackenzie's tally of deferred upstream projects it has tracked since the oil price collapse started in 2014 now sits at 68 major projects containing 68Bboe, which equates to the $380 billion figure of total project spend in real terms.

The firm expects this list to grow further - and that growing figure is big enough to have a material impact on global supply, which could be good news for oil prices longer-term.

This would be an ironic kind of vindication for Saudi Arabia's dogged determination to let the market do its thing rather than act to cut production to stem the blood-letting among both non-OPEC oilers and OPEC's own struggling economies alike, like Venezuela.

In June last year, Wood Mackenzie estimated the delayed projects accounted for about 1MMbpd of liquids output by 2021, rising to just under 2MMbpd by 2025, but with more deep water oil projects getting pushed back, the impact six months later is significantly greater.

The firm estimates 1.5MMbpd to have been delayed by 2021, rising sharply to 2.9MMbpd by 2025.

The slump in oil prices that has smashed market capitalisations of every Australian oil company since 2014 will have a lasting impact beyond that, with Wood Mackenzie saying that FIDs on many of the delayed projects have been pushed back to 2017 or beyond.

"Against the backdrop of overwhelming corporate pressure to free-up capital and reduce future spend, investment/output will be pushed back further if prices do not recover," the firm said.

While deep water has been hit the hardest, it could also be the industry's salvation. In fact, Wood Mackenzie says it was not being disregarded as an investment theme, despite $170 billion of potential investment currently hanging in the balance across those aforementioned 68 projects.

This figure is disproportionately weighted towards deep water projects where half of new projects have been deferred, up from 17 to 29.

"Deepwater has suffered due to the combination of insufficient cost deflation and significant upfront capital spend discouraging companies from greenfield investment in the sector," Wood Mackenzie said.

Yet the firm believes a trend is evolving in which companies are taking more time to re-work development solutions and the industry is starting to agree there is considerable scope for standardisation.

"Such structural changes take time to develop and implement, but the need to improve deep water development economics is strong," the firm said.

While industry sentiment is at a low as 2016 kicks off with Iranian oil set to hit the market any time now, and the possibility of an imminent wave of new FIDs is therefore slim, Wood Mackenzie says the adverse market conditions could have a longer term positive impact.

"Companies are being forced to find new ways to develop large, high-cost conventional resources. This will encourage a renewed focus on standardisation and innovation," the firm said.