With the USA increasingly exporting oil, weather disturbances can also cause price increases.
At 10:30 am Singapore time (0230 GMT), ICE November Brent crude futures were down a marginal 3 cents/b (0.04%) from Monday's settle at $78.12/b, while the NYMEX October light sweet crude contract was 26 cents/b (0.37%) higher than Friday's settle at $70.06/b.
Many global shippers have stopped loading Iranian oil as US financial sanctions against Tehran prevents them from insuring its cargoes.
There hasn't been much excitement in the market as investors were out due to summer holidays or Labor Day.
Crude oil prices are now slightly higher.
The oil price is higher Tuesday, amid news Anadarko petroleum has evacuated its two rigs based in the Gulf of Mexico, as Hurricane Gordon approaches the area.
They added: "The impact of the sanctions will spark further civil unrest and public discontent as Iranians struggle to cope with deteriorating economic conditions, increasing unemployment and rapidly rising price levels". The shutdown of the two rigs is exacerbating existing fears over future oil production capacity, as the date on which US Iran oil sanctions are in place, draws closer.
Turning to Brent crude, India has allowed state refiners to buy Iranian crude oil if the country is willing to insure tankers.
FGE estimates Iran's exports will slump to below 1 million barrels a day by mid-2019, while industry consultant Energy Aspects Ltd. expects a plunge of 1.5 to 1.7 million in daily shipments by the end of this year from current levels of about 2.5 million.
"U.S. producers are resisting temptation and exercising capital discipline, OPEC and Russian Federation have convinced market participants they are managing the supply of over half of global production, the U.S.is using sanctions more actively, and several key OPEC producers are at risk of being failed states", Barclays said.
Japanese refiner Cosmo Oil said Tuesday it does not plan to load any crude oil from Iran in October, while it is still monitoring the progress of bilateral talks between Japan and the United States to make a final decision on its Iran oil import policy.
Japan's major oil distributors, taking heed of US demands, are expected to suspend crude imports from Iran in October and switch to other producers in the Middle East, sources with knowledge of the plans say.
The average retail price for a liter of regular has been above ¥150 since late May.