January West Texas Intermediate crude lost $1.66, or 2.9%, to settle at $55.96 a barrel on the New York Mercantile Exchange-for its lowest finish since November 16, according to FactSet data.
Shortly after data release, the WTI benchmark was down 0.35% on the day to $57.67 at 4:38pm EST.
Gasoline stocks tend to build in December, but at 221 million barrels of inventory, stocks are slightly above the five-year average for this time of year.
The API report was also said to find that crude inventories slid by 5.48 million barrels last week and supplies at the key Cushing, Oklahoma, pipeline hub declined by 1.95 million barrels, the people said.
Gasoline futures led the energy complex lower on Wednesday, as RBOB dropped 3 percent to $1.6658 a gallon.
Google Hiring Thousands of Moderators To Clean Up YouTube
Wojcicki says YouTube will also use technology to flag "problematic" videos or comments that show hate speech or harm to children. On December 4, Alphabet-owned YouTube announced to expand its team of reviewers to manage extremist, violent content by 2018.
Among the heating fuels, January heating oil settled at $1.861 a gallon, down 2.8%.
US output rose in September to 9.5 million barrels per day (bpd), the highest monthly output since 2015, the EIA said last week.
Supply cuts by the Organization of the Petroleum Exporting Countries, Russia and other producers that were extended at a meeting last week for the rest of 2018 have helped lift Brent prices by more than 40% since June.
The Organization of the Petroleum Exporting Countries and its allies, including non-OPEC Russia, agreed last week to extend a deal to hold down crude output (http://www.marketwatch.com/story/heres-what-opecs-extended-oil-production-cuts-mean-for-the-market-2017-11-30) by almost 2% through the end of next year. WTI Oil slipped under $57 per barrel and took a hefty tumble as equities plunged around Asia and Europe. Analysts such as Goldman Sachs have said that the expected rise in demand in 2018 would mostly be offset by USA and Canadian supply growth.
One factor that could undermine OPEC's and Russia's effort to cut supplies and prop up prices is United States oil production, which has risen by 15% since mid-2016 to 9.68 million barrels per day, close to levels of top producers Russian Federation and Saudi Arabia. An extension had been largely priced in but rising USA oil production has been a key concern for the market.