A oil pump is seen at sunset outside Scheibenhard, near Strasbourg, France, October 6, 2017 . REUTERS/Christian Hartmann 

The Cuban and Chinese national flags fly next to each other at an oil rig of the Great Wall Drilling Company, a subsidiary of China National Petroleum Corp (CNPC), near Varadero, around 140 kilometres (86 miles) east of Havana, September 4, 2011. China has signed an agreement to play a major role in increasing Cuban oil production both onshore and offshore, although details were not disclosed. State-owned CNPC is said to be considering leasing exploration blocks in Cuban waters. China also committed to negotiations of contracts for a $6 billion expansion of Cuba's Cienfuegos refinery and a liquefied natural gas project. Picture taken September 4, 2011. REUTERS/Desmond Boylan (CUBA - Tags: ENERGY POLITICS BUSINESS) 

An oil rig of the Great Wall Drilling Company, a subsidiary of China National Petroleum Corp (CNPC), is seen near Varadero, around 140 kilometres (86 miles) east of Havana, September 4, 2011. China has signed an agreement to play a major role in increasing Cuban oil production both onshore and offshore, although details were not disclosed. State-owned CNPC is said to be considering leasing exploration blocks in Cuban waters. China also committed to negotiations of contracts for a $6 billion expansion of Cuba's Cienfuegos refinery and a liquefied natural gas project. Picture taken September 4, 2011. REUTERS/Desmond Boylan (CUBA - Tags: ENERGY BUSINESS POLITICS) 

Workers stand near pipes while setting up an oil rig near the coast on the outskirts of Havana May 24, 2010. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: ENVIRONMENT ENERGY BUSINESS DISASTER) 

Workers set up an oil rig near the coast on the outskirts of Havana May 24, 2010. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: ENVIRONMENT ENERGY DISASTER BUSINESS) 

An oil pump is pictured near the coast on the outskirts of Havana May 24, 2010. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: ENVIRONMENT ENERGY DISASTER BUSINESS) 

Pipes connected to an oil pump are pictured near the coast on the outskirts of Havana May 24, 2010. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: ENVIRONMENT ENERGY DISASTER BUSINESS) 

Pipes connected to an oil pump are pictured near the coast on the outskirts of Havana May 24, 2010. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: ENVIRONMENT ENERGY BUSINESS DISASTER) 

A worker holds a pipe while setting up an oil rig near the coast on the outskirts of Havana May 24, 2010. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: DISASTER ENERGY BUSINESS ENVIRONMENT) 

An oil boom sits in a pile after being washed up onshore on Horn Island, Mississippi May 11, 2010. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT BUSINESS) 

A member of a clean-up crew combs the beach for tar balls washed ashore on Dauphin Island, Alabama May 10, 2010 two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

Crews build a sand berm to protect the island from the potential of oil washing onshore, on Dauphin Island, Alabama May 10, 2010. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

Clean-up crews (top) comb the beach on Dauphin Island, Alabama May 10, 2010 two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

Air quality monitoring equipment is installed on the pier at the beach on Dauphin Island, Alabama May 10, 2010, two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

Air quality monitoring equipment is installed on the pier at the beach on Dauphin Island, Alabama May 10, 2010, two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

A clean-up crew marks a dead fish on the beach on Dauphin Island, Alabama May 10, 2010, two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

Three-year-old Morgan Edmonds (L) plays in the surf as a clean-up crew combs the beach on Dauphin Island, Alabama May 10, 2010, two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

Clean-up crews comb the beach on Dauphin Island, Alabama May 10, 2010 two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

Three-year-old Morgan Edmonds (L) plays in the surf as a clean-up crew combs the beach on Dauphin Island, Alabama May 10, 2010, two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

Clean-up crews (top) comb the beach on Dauphin Island, Alabama May 10, 2010 two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

A dead fish is marked by clean-up crews on the beach on Dauphin Island, Alabama May 10, 2010, two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT ANIMALS) 

Members of a clean-up crew comb the beach on Dauphin Island, Alabama May 10, 2010, two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

Clean-up crews (top) and beachgoers pass one another at the beach on Dauphin Island, Alabama May 10, 2010, two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT) 

Three year-old Morgan Edmonds plays in the surf as a clean-up crew combs the beach on Dauphin Island, Alabama May 10, 2010, two days after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT IMAGES OF THE DAY) 

A crab sits on the shoreline on the beach on Dauphin Island, Alabama May 9, 2010, one day after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT ANIMALS) 

Birds walk on the beach on Dauphin Island, Alabama May 9, 2010, one day after tar balls washed up onshore. Oil workers, volunteers and the military have been battling to shut off a gushing oil leak in the Gulf of Mexico and stop the huge spreading slick from reaching major ports, tourist beaches, wildlife refuges and fishing grounds. REUTERS/Brian Snyder (UNITED STATES - Tags: DISASTER ENERGY ENVIRONMENT IMAGES OF THE DAY) 

A boom to protect against oil from the Gulf of Mexico spill sits broken onshore off Freemason Island, Louisiana May 8, 2010. REUTERS/Lee Celano (UNITED STATES - Tags: DISASTER ENVIRONMENT) 

A driver waits to refuel his car at a gas station in Havana May 7, 2010. Spanish oil giant Repsol YPF has contracted with a unit of Italian oil company Eni SpA for a drilling rig that some sources said was bound for operation in Cuba's still untapped offshore fields. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: ENERGY BUSINESS TRANSPORT) 

A Chevrolet 1955 car is driven out of a petrol station after refueling in Havana May 7, 2010. Spanish oil giant Repsol YPF has contracted with a unit of Italian oil company Eni SpA for a drilling rig that some sources said was bound for operation in Cuba's still untapped offshore fields. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: ENERGY TRANSPORT BUSINESS) 

Exhaust gases from an oil rig burn near the village of Cojimar on the outskirts of Havana May 7, 2010. Spanish oil giant Repsol YPF has contracted with a unit of Italian oil company Eni SpA for a drilling rig that some sources said was bound for operation in Cuba's still untapped offshore fields. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: ENERGY BUSINESS) 

An oil rig stands near the village of Cojimar on the outskirts of Havana May 7, 2010. Spanish oil giant Repsol YPF has contracted with a unit of Italian oil company Eni SpA for a drilling rig that some sources said was bound for operation in Cuba's still untapped offshore fields. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: ENERGY BUSINESS) 

An oil rig is lit up beside the coast near the village of Cojimar on the outskirts of Havana May 7, 2010. Spanish oil giant Repsol YPF has contracted with a unit of Italian oil company Eni SpA for a drilling rig that some sources said was bound for operation in Cuba's still untapped offshore fields. Cuba estimates it has 20 billion barrels of oil in its part of the Gulf of Mexico, which abuts the oil-rich U.S. and Mexican zones of the gulf, and Havana views its possible production as a godsend. The communist-led island produces about half its energy needs from onshore wells and gets the rest from oil-rich socialist ally Venezuela at favorable prices. REUTERS/Desmond Boylan (CUBA - Tags: ENERGY BUSINESS) 

A Rosneft worker walks near a nodding donkey at the Yuganskneftegaz oil production station near the Siberian town of Nefteyugansk, some 3,000 km (1,863 miles) east of Moscow April 26, 2006. Russian state oil giant Rosneft and private major Surgutneftegaz won auctions on Tuesday for large oilfields in East Siberia as they prepare to be the key shippers via a pipeline to Asia. REUTERS/Sergei Karpukhin