Oil prices remained unchanged following a fall in the US crude inventories and robust demand for refinery.

Brent crude for August was trading at $57.05 a barrel, while the US light crude, also known as West Texas Intermediate or WTI, increased 10 cents at $51.51, Reuters reported.

The Energy Information Administration (EIA) reported a decline in the US crude inventories by 4.3 million barrels last week following an increase in output by refineries.

"Although Iran has around 20 million barrels of oil in storage, some of it is needed for operational reasons domestically and is not destined for export."

According to Phillip Futures’ Daniel Ang, the crude inventory figures in the US looked bullish for both global oil benchmarks.

However, the oversupply concerns remain due to excess production of crude by the Organization of the Petroleum Exporting Countries (OPEC), which analysts said produced around 2.5 million barrels per day (bpd).

As Iran reached a deal with six global powers over its nuclear programme, the oil production set to rise by OPEC countries.

The country had been exporting about three million bpd prior to the imposition of sanctions which had come down to one million bpd over the last two years.

Energy consultancy Wood Mackenzie told the news agency: "Although Iran has around 20 million barrels of oil in storage, some of it is needed for operational reasons domestically and is therefore not destined for export."