- Iran exports close to 1.5 million bpd of crude in the first two weeks of October, down from from 2.5 million bpd in April.
- Saudi Arabia continues to face political pressure over the disappearance of journalist Jamal Khashoggi.
- Oil production from seven major U.S. shale basins is expected to rise by 98,000 barrels per day (bpd) in November to a record of 7.71 million bpd.
Oil prices rose in cautious trade on Tuesday as expectations of higher U.S. shale output and inventories vied with worries that crude supply from the Middle East could be disrupted by looming U.S. sanctions on Iran and growing tensions with top producer Saudi Arabia.
The disappearance of a Saudi Arabian journalist Jamal Khashoggi in Turkey has strained U.S.-Saudi ties and provoked international outcry and fears that supplies from the world's top crude exporter may be affected.
U.S. Senator Lindsey Graham accused Saudi Crown Prince Mohammed bin Salman of ordering the murder of Khashoggi and said the prince was jeopardizing relations with the United States.
"The focus within the oil trade during the next couple of weeks is likely to be on Iran and Saudi Arabia," Jim Ritterbusch, president of Ritterbusch and Associates, said in a note.
"We don't expect the Kingdom to be as accommodative to the White House requests for stronger production," he said, adding that the Saudis could cut as much as 500,000 barrels per day of production "as a warning shot should the U.S. opt to impose any type of sanction in response to the Khashoggi developments."
Reports that Iranian exports of crude oil may be falling faster than expected ahead of new U.S. sanctions on Tehran from Nov. 4 lent support.
In the first two weeks of October, Iran exported close to 1.5 million bpd of crude to countries including India, China and Turkey, some industry sources suggest.
That is a sharp drop from 2.5 million bpd in April before U.S. President Donald Trump withdrew from a nuclear deal with Iran in May and ordered the re-imposition of sanctions.
Market participants said U.S. crude prices were being capped by recent stock builds at Cushing, Oklahoma, the delivery point for WTI, where inventories have risen for three straight weeks.
Data from the American Petroleum Institute (API) is due at 4:30 p.m. EDT (2030 GMT) while the U.S. Department of Energy will release official data at 10:30 a.m. EDT (1430 GMT) on Wednesday.
In addition, weak U.S. gasoline margins and growing U.S. shale output could cap gains, market participants said.
"The weakening crude spreads almost globally in the face of Iran sanctions is likely generating some concern on how strong market really is and if it's ready to rally more," said Scott Shelton, energy futures broker with ICAP in Durham, North Carolina.
Front-month Brent crude futures traded at the lowest premium in over a month to futures for delivery one year from now. Meanwhile, front-month U.S. crude futures traded near the smallest premium to the 12th month in about 10 months.
Oil production from seven major U.S. shale basins is expected to rise by 98,000 barrels per day (bpd) in November to a record of 7.71 million bpd, the U.S. Energy Information Administration (EIA) said.
OPEC Secretary-General Mohammad Barkindo said oil markets were currently adequately supplied and balanced, but urged oil producing companies to increase capacities and invest more to meet future demand as spare oil capacity shrinks worldwide.