petroleum

50 countries have it in the ground.

Country
Afghanistan
Albania
Algeria
Angola
Azerbaijan
Barbados
Bolivia
Brunei
Cameroon
Chad
Colombia
Democratic Republic of the Congo
Denmark
Ecuador
Egypt
El Salvador
Equatorial Guinea
Gabon
Greece
Guatemala
Indonesia
Iran
Iraq
Kingdom of the Netherlands
Kuwait
Libya
Malaysia
Mexico
Myanmar
Nigeria
Norway
Oman
People's Republic of China
Peru
Philippines
Qatar
Republic of the Congo
Romania
Saudi Arabia
South Sudan
Syria
Timor-Leste
Trinidad and Tobago
Tunisia
Turkmenistan
United Arab Emirates
United Kingdom
Uzbekistan
Venezuela
Yemen