Wood Mackenzie, a global energy research company, said the region with the most valuable portfolio is the Middle East, where the 367 billion barrels of undeveloped oil and natural gas discoveries could be worth $185 billion.
"These include the undeveloped volumes in the super-giant North/South Pars gas field which extends between Qatar and Iran in the Persian Gulf," David Highton, principal analyst for upstream research, said Thursday. "Combining both countries' share, this is the largest single technical reserve in the world."
Highton said, however, the regions with the largest volumes are often "difficult or impossible" to work, including parts of the Middle East.
Overall, Wood Mackenzie said there may be 1.4 trillion barrels of conventional undeveloped oil and natural gas left in the world worth an estimated $760 billion.
"There are a number of obstacles and complexities which continue to hamper efforts to tap into the $760 billion prize," Highton said. "These could be the lack of accessible markets or available infrastructure, political or environmental issues, operator constraints, or simply low resource volumes for the particular location."
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