Benchmark Brent crude oil futures LCOc1 rose to as much as $83.32 a barrel on Wednesday and were at $83.09 at 0335 GMT, still 36 cents, or 0.4 percent above their last close.
U.S. West Texas Intermediate (WTI) crude futures CLc1 were up 19 cents, or 0.3 percent, at $73.44 a barrel.
WTI prices were supported by a report on Friday of a stagnant rig count in the United States, which points to a slowdown in U.S. crude production C-OUT-T-EIA, which now rivals top producers Russia and Saudi Arabia.
Brent was pushed up by looming sanctions against Iran, which will start targeting its oil sector from Nov. 4.
ANZ bank said on Monday that the market is eyeing oil prices at $100 per barrel.
In a sign that the financial market is positioning itself for further price rises, hedge funds increased their bullish wagers on U.S. crude in the week to Sept. 25, data from the U.S. Commodity Futures Trading Commission (CFTC) showed on Friday, increasing futures and options positions in New York and London by 3,728 contracts to 346,566 during the period.
In a further sign of the impact that the U.S. sanctions on Iran will have on the market, Chinas Sinopec (600028.SS) said it is halving loadings of Iranian crude oil this month. China is the biggest buyer of Iranian oil.
If Chinese refiners do comply with U.S. sanctions more fully than expected, then the market balance is likely to tighten even more aggressively, Edward Bell, commodity analyst at Emirates NBD bank wrote in a note published on Sunday.
Trading activity will be low in China this week due to the Golden Week holiday there.
U.S. President Donald Trump called Saudi Arabias King Salman on Saturday, discussing ways to maintain sufficient supply once Irans exports are hit by sanctions.
Until sizable supply is offered up by OPEC, ultimately traders will continue to push the envelope even more, said Stephen Innes, head of trading for Asia-Pacific at futures brokerage Oanda in Singapore.
Even if they (Saudi Arabia) wanted to bend to President Trumps wishes, how much spare capacity does the Kingdom have? he asked.
Were going to find out very soon as approximately 1.5 million barrels (per day) of Iranian oil is effectively going offline on Nov. 4. If the market senses that Saudi Arabia capacity is tapped out at 10.5 million bpd ... oil prices will rocket higher with the flashy $100 per barrel price tag indeed a reasonable sounding target, Innes said.
LOOMING SLOWDOWN?
With oil prices soaring, there are concerns over their inflationary effect on demand growth, especially in Asias emerging markets where weakening currencies are further adding to high fuel import costs.
Add the trade disputes between the United States and other major powers, especially China, and economic growth into 2019 could be eroded.
Growth in Chinas manufacturing sector already sputtered in September as both external and domestic demand weakened, two surveys showed on Sunday.
In Japan, business confidence among big manufacturers declined in the last quarter its lowest in nearly a year, as firms felt the pinch from rising raw material costs and as global trade conditions worsened.
(GRAPHIC: Oil prices in different currencies -tmsnrt.rs/2OffFwp)
Reporting by Henning Gloystein; Editing by Christian Schmollinger and Richard Pullin
