The Iranian Minister of Oil Bijan Namdar Zanganeh received a British delegation headed by the British Foreign Secretary Philip Hammond in Tehran on Sunday to discuss ways for opening a new chapter in oil cooperation of Tehran and London in post-sanctions era.

The British official was accompanied by representatives from British companies, including Deputy Managing Director of Royal Dutch Shell Company. Shell has a history of activities in Iran’s upstream projects, including in South Pars, but the firm pulled out of the world’s largest gas field’s Phase 13 development in 2008.

Shell also operated Iran’s Soroush and Nowruz oilfields in the Persian Gulf with a capacity of 200,000 barrels per day. An outstanding debt to the tune of $2.3 billion has remained unpaid by the company to Iran since 2012.

Iran wants to unveil its new energy contracts at a conference planned for December in London.

Deputy Oil Minister Amir Hossein Zamaninia told a Vienna conference recently that Iran has identified nearly 50 oil and gas projects worth $185 billion up for grab.

Shell and other European energy giants such as France’s Total, Italy's Eni and BP had built strong relationships with Iran through work in the country's oil and gas fields as well as crude oil purchases before halting them under sanctions.

Shell was Iran's second biggest corporate client along with Total in 2012 when the Anglo-Dutch company lifted 100,000 barrels of crude oil per day.

Executives from Eni and Shell traveled to Tehran in June and May to discuss new opportunities in the resource-rich country and outstanding debts.

On Thursday, Eni’s Chief Executive Officer Claudio Descalzi said his company was interested in returning to Iran once the sanctions ended.

Meanwhile, BP Chief Executive Bob Dudley said his company was looking for opportunities in Iran’s upstream oil industry.

Iran’s Minister of Oil Bijan Zangeneh said he looked for 'a new chapter' in cooperation with Total as French Foreign Minister Laurent Fabius visited Tehran.