New Delhi, June 15: Global oil giant Saudi Aramco and Abu Dhabi National Oil Co have expressed their interest in buying a stake in the world's biggest refinery-cum-petrochemical complex coming up in Ratnagiri district of Maharashtra at an estimated cost of $40 billion.

The 60-million-tonne-per-annum complex is expected to be commissioned by 2022.

Oil minister Dharmendra Pradhan said Khalid A Al-Falih, Saudi Arabia's energy minister and the chairman of Saudi Aramco, had expressed interest in picking up a stake in the complex during his meeting in Vienna last month.

"He was very categorical that Saudi Aramco is very keen to partner the mega refinery from the very start," he said after state-owned oil companies IOC, Bharat Petroleum Corp (BPCL) and Hindustan Petroleum Corp (HPCL) signed a joint venture agreement to set up the mega complex.

While Aramco is eyeing a stake in the the west-coast refinery, Abu Dhabi National Oil Co (Adnoc) is keen on the petrochemical projects.

Sources indicated that the Saudi company was keen on being the sole or the largest supplier of fuel to the refinery as a rider for picking up a stake.

However, India is not keen on restricting its fuel options, since the refinery will be processing different grades of crude.

IOC will initially hold a 50 per cent stake in the project, while BPCL and HPCL will own 25 per cent each.

If a new strategic partner comes in, their stakes will come down proportionately. However, state-owned companies will have the majority stake, sources said.

"The proposed west coast refinery-cum-petrochemical complex will be the largest in the world, equipped with the best refining technologies," IOC chairman Sanjiv Singh said.

Designed to produce transportation fuel for Euro-VI and above grades, the refinery will have in-built flexibility to process a wide spectrum of light and heavy crude, using various blending techniques.

Iran treaty

Expressing displeasure at the treatment meted out by Iran, Pradhan said India expected Tehran to reciprocate by awarding the rights of the coveted Farzad-B gas field to its discoverer, ONGC.

"We value relationships. During the difficult days of Iran, when the entire West had imposed sanctions, we stood by them and bought a substantial amount of crude oil. We also returned every penny when the banking channels reopened," he said.