No. 96: Indian Oil
No. 84: PTT
Marathon Oil / Marathon Oil
No. 81: Marathon Petroleum
A Marathon Oil drilling rig works in the Bakken Shale of North Dakota.
No. 79: China National Offshore Petroleum
Lai Seng Sin / AP
No. 69: Petronas
Malaysia's landmark Petronas Twin Towers before the lights were turned off to mark Earth Hour.
No. 64: SK Holdings
Country: South Korea
Kent Skibstad / Associated Press
No. 54: Statoil
The head office of Statoil in Stavanger, Norway is pictured in this file photo dated Jan. 18, 2013.
No. 51: JX Holdings
Andrey Rudakov / Bloomberg
No. 46: Rosneft Oil
An OAO Rosneft logo sits on a display stand the company's corporate pavilion during the World Petroleum Congress in Moscow, Russia, on Monday, June 16, 2014.
ERIC PIERMONT / AFP/Getty Images
No. 44: GDF Suez
This photo taken on February 26, 2014 shows the tower of French energy company GDF Suez in La Defense district in Courbevoie, near Paris.
Alexander Zemlianichenko Jr. / Bloomberg
No. 43: Lukoil
Pedestrians pass the entrance to the headquarters of OAO Lukoil in Moscow, Russia, on Wednesday, June 25, 2014.
FEDERICO PARRA / AFP/Getty Images
No. 41: PDVSA
Venezuela's Minister of Petroleum and Mining and president of the state-owned oil company PDVSA, Rafael Ramirez, gives the 2013 annual report of the company, at its headquarters in Caracas, on June 27, 2014.
Susana Gonzalez / Bloomberg
No. 36: Pemex
Lights illuminate a section of Pemex Pol-A Platform complex, located on the continental shelf in the Gulf of Mexico, 70 kilometers offshore from Ciudad del Carmen, Mexico, on Friday, March 28, 2014.
David Paul Morris / Bloomberg
No. 30: Valero
Vehicles drive past a Valero Energy Corp. fueling station in San Francisco, California in this April 25, 2014 file photo.
Felipe Dana / ASSOCIATED PRESS
No. 28: Petrobras
This Thursday, Oct. 28, 2010 file photo shows a view of the Petrobras offshore ship platform FPSO Cidade de Angra dos Reis.
No. 22: ENI
An undated handout photo made available by the ENI press office, shows the the Italian oil and gas company's gas compression plant settled on the shore of Mellitah, Libya.
Lisa Poole / Associated Press
No. 19: Phillips 66
In this Oct. 26, 2009 file photo, a customer fuels up his car at a Phillips 66 gas station in Woburn, Massachusetts.
No. 18: E.ON
Alexander Zemlianichenko / Associated Press
No. 17: Gazprom
The headquarters of Russia's state-run natural gas giant Gazprom is seen during the company's annual shareholders' meeting in Moscow, Russia, Friday, June 27, 2014.
Elaine Thompson / Associated Press
No. 12: Chevron
In this May 23, 2013, photo, a United States flag flies in view of a Chevron gas station in Blaine, Washington.
Balint Porneczi / Bloomberg
No. 11: Total
The Total SA company sign is seen outside their headquarters in the La Defense business district in Paris, France, on Monday, April 2, 2012.
No. 10: Glencore
KAREN BLEIER / AFP/Getty Images
No. 6: BP
Country: United Kingdom
In this September 20, 2008 file photo, British Petroleum sign is seen at a station in Manassas, Virginia.
Gene J. Puskar / Associated Press
No. 5: Exxon Mobil
This Jan. 27, 2011 file photo shows an Exxon sign in Carnegie, Pennsylvania.
China Photos / Getty Images
No. 4: China National Petroleum
A car is parked in front of a billboard for China National Petroleum Corporation in this July 7, 2008 file photo taken in Beijing, China.
Andrey Rudakov / Bloomberg
No. 3: Sinopec Group
A logo sits on display at the China Petroleum & Chemical Corp. (SINOPEC) pavilion during the World Petroleum Congress in Moscow, Russia, on June 16, 2014.
Rich Pedroncelli / Associated Press
No. 2: Royal Dutch Shell
Country: The Netherlands
In this photo taken Friday March 7, 2014, gas prices are displayed at a Shell station.