oil reserves

noun

1. Large amounts of crude oil known or believed to exist underground that can be extracted profitably.

   B2

   plural; often used with “proven”, “estimated”, or “remaining”

   • "The country has large oil reserves."B1
   • "New technology allowed companies to access oil reserves that were once too difficult to reach."B2
   • "Geologists estimate that the region's oil reserves will last another thirty years."C1

2. Stocks of oil kept by a government or company for use in an emergency or when supplies are interrupted.

   B2

   plural; often used as “strategic oil reserves”

   • "The government released oil reserves to lower fuel prices."B1
   • "Strategic oil reserves can help a country during a supply crisis."B2
   • "Members agreed to coordinate the release of emergency oil reserves."C1