Saudi Aramco, an oil and gas giant, intends to purchase British-Dutch peer Shell's 50 percent stake in Saudi Aramco Shell Refinery Co., the companies' refining joint venture (JV).

Saudi Aramco, expecting to pay $631 million for the stake in the JV, said that the deal is part of its long-term downstream growth strategy as it aims to boost the complexity and capacity of its refineries.

Furthermore, the sale provides Shell with the opportunity to focus on its refining portfolio, integrating with its trading hubs and chemicals.

The transaction, pending regulatory approval, is expected to close later this year. On the closure of the move, Saudi Aramco will take full ownership and integrate the refinery into its growing downstream portfolio.