The U.S. will become the world's biggest oil producer within two years, but rising global supplies of shale and other unconventional oils will not reduce the need for OPEC's oil over the next two decades, the Paris-based International Energy Agency said on Nov. 12.

Non-OPEC oil production will rise to 52.9 million barrels per day (bpd) in 2035, up from 49.4 million bpd in 2012 but down from a peak of 55.1 million bpd in 2025, the IEA said in its annual World Energy Outlook report.

During that period, supplies of unconventional non-OPEC oil, such as light, tight oil from the U.S. and Canadian oil sands, will swell to make up 12.3 million bpd of the total from 4.4 million in 2012, the IEA said. U.S. production of light, tight shale oil will help the country's output peak at 11.8 million bpd in 2025, before slipping to 10.9 million by a decade later, according to the report.

"The United States moves steadily toward meeting all of its energy needs from domestic resources by 2035," the IEA said in the report, noting that U.S. imported crude needs will almost disappear by 2035.

Even by 2015, the U.S. likely will overtake Saudi Arabia as the biggest oil producer in the world, the IEA said.

"On the assumption that Saudi Arabia reins back production levels in its capacity as the swing producer within OPEC, this means that the United States becomes the largest oil producer in the world (including crude, natural-gas liquids and unconventional oil) by 2015 and retains this status until the beginning of the 2030s," the IEA said.

Holistic Lens

Separately, in a Nov. 14 report, management consultant PwC, a unit of PricewaterhouseCoopers LLP, notes how U.S. engineering and construction firms speed delivery and cut costs for shale-oil project clients.

“Given the high stakes, cost pressure and intense competition in the shale industry, oil and gas companies are learning to apply a holistic lens to all aspects of shale development and managing them from end to end,” says report author John Doherty, engineering and construction advisory leader for the U.S. unit of PwC. “This creates an opportunity for engineering and construction firms to become a key asset in the process, as they adjust their traditional project management model and create fast-response systems to the changing environment.”

According to the report, E&C firms can cut annual costs by up to 25% and project development "cycle time" by as much as 40% "by tightening the functional handoffs and improving the line of sight between demand in the field and organizational capacity."

The firm suggests that E&C companies assist their clients in project planning and field execution through effective communication and integration of business data systems, among other strategies.

Despite recent project delays, the IEA said Brazil's massive deepwater-fields developments will triple the country's current crude-oil output to 6 million bpd by 2035, up from an estimated 5.7 million bpd the year before.

OPEC Remains Key Supplier

But global shale-oil development will struggle to replicate the success of the U.S., and unconventional oil from non-OPEC producers will fail to reduce the world's dependence on OPEC oil, the IEA said.

According to the IEA estimates, production of light, tight oil does not "take off at scale" outside North America before 2035 but still reaches 5.9 million bpd by the mid-2020s.