U.S. oil futures extended losses after data from the American Petroleum Institute showed a 3.8 million inventory build.
The front-month contract for West Texas Intermediate (WTI) fell to $29.63 after it settled at $29.88 a barrel, down 5.5 percent, or $1.74.
Brent for April delivery dropped $1.79, or 5.23 percent, to $32.43 a barrel, after touching a low of $32.23, down 5.9 percent, in the session.
In pre-settlement trade, oil fell sharply for the second straight day on Tuesday as hopes of a deal to curb one of the worst supply gluts in history continue to fade and concerns about weak demand amid a mild winter deepen the rout.
The oil markets erased most of last week's four-day rally, during which prices soared almost 20 percent from the lows touched in mid-January after Russia's Energy Minister said OPEC kingpin Saudi Arabia suggested a production cut.
This week though, those hopes have dimmed as no deal has emerged and talks between Russia's energy minister and Venezuela's oil minister on Monday failed to produce any clear plan to reduce output.
With forecasters projecting the weather in the United States will moderate during the last eight weeks of the November-March winter heating season, U.S. heating oil futures were down 2 percent and gasoline was 6 percent lower.
"For whatever reason, there's a lot of hope that some deal will be pulled off," said John Kilduff, partner at Again Capital LLC in New York.
"As they continue to disappoint, we're going to trade lower, until the market forces them to do something and I think that's at a much lower price than here."
Goldman Sachs said it was "highly unlikely" the Organization of the Petroleum Exporting Countries would cooperate with Russia to cut output, saying such a move would also be self-defeating as stronger prices would bring previously shelved production back to the market.
"It's hard to see a successful agreement between OPEC and Russia to cut production and people are starting to see that," said Andy Sommer, senior energy analyst at Axpo Trading in Dietikon, Switzerland.
Prices are in danger of returning to the $20s unless there was concrete reaction on the supply side, said Thomas Saal, analyst at INTL FC Stone in Miami, Florida.
Still, Citi called a bottom on prices on Tuesday, saying that even while a deal may not materialize, the current lows will be short lived.
Oil stockpiles are still on the rise, with Russian output hitting a post-Soviet high in January, while U.S inventories forecast to have added 4.8 million barrels to record supplies last week.
The American Petroleum Institute (API) will release its data at 4:30 p.m. EST (2130 GMT), ahead of the government's report on Wednesday.
Meanwhile, the prolonged downturn in crude prices has crushed the oil majors' results.
Exxon Mobil Corp, the world's largest publicly traded oil company, reported its smallest quarterly profit in more than a decade and said it will cut 2016 spending by one-quarter, while BP reported to its biggest annual loss and announced thousands more job cuts.
U.S. shale producers, seen as resilient in the face of plunging prices, expanded capital spending cuts last week, in what most believed was a sign of capitulation.
The fall in oil prices has put pressure on Iran, but there is also opportunity, Iranian President Hassan Rouhani said on Tuesday, urging diversification in the economy.
He said the economy should become less reliant on oil and look to other industries for revenue. "Even if the oil price rises, we should rely more on non-oil exports," he said.