Pipes for TransCanada's planned Keystone XL pipeline are stored in Gascoyne, N.D. The U.S. House has voted to approve the proposed project, which would allow crude oil to flow from Canada to the Gulf of Mexico. The Senate plans to vote Tuesday on legislation that would greenlight the project. Andrew Cullen/Reuters/Landov hide caption

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Ray Gerrish repairs a drilling rig near Watford City, N.D. Oil industry analysts predict that oil prices will have to remain low for at least several months before having a significant effect on U.S. production. Jim Gehrz/MCT/Landov hide caption

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Pumpjacks at the Inglewood oil fields in California in March. Some of the most controversial methods of oil extraction, like fracking, oil sands production and Arctic drilling, are also expensive. That's made them less profitable as the price of oil continues to fall. Richard Vogel/AP hide caption

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U.S. Secretary of State John Kerry speaks with Saudi King Abdullah bin Abdul Aziz al-Saud as the Saudi ambassador to the United States, Adel al-Jubeir, listens before a meeting at the Royal Palace in Jiddah, Saudi Arabia, on Sept. 11. Brendan Smialowski/AFP/Getty Images hide caption

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Saudi Arabia's oil minister, Ali Al-Naimi, shown in Kuwait last month, has played down the drop in oil prices. The country continues to pump oil at high levels, saying it wants to preserve its market share. But this has also contributed to a 25 percent drop in oil prices since June. Yasser Al-Zayyat/AFP/Getty Images hide caption

itoggle caption Yasser Al-Zayyat/AFP/Getty Images

A soldier guards a pipe en route to the Kawergosk Refinery near Irbil, the capital of the autonomous Kurdish region of northern Iraq, in July. Fighting in northern Iraq forced the closure of the country's largest oil refinery, Baiji, and cut production from the Kirkuk oil field this summer. Safin Hamed/AFP/Getty Images hide caption

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