A company logo sits on the side of a crude oil storage tank at the Juaymah tank farm at Saudi Aramco's Ras Tanura oil refinery and oil terminal in Ras Tanura, Saudi Arabia, on Monday, Oct. 1, 2018. Saudi Aramco aims to become a global refiner and chemical maker, seeking to profit from parts of the oil industry where demand is growing the fastest while also underpinning the kingdom?s economic diversification. Photographer: Simon Dawson/Bloomberg

(Bloomberg) -- Saudi Aramco agreed to buy an additional stake in PetroRabigh from its joint venture partner Sumitomo Chemical Co. for about $700 million.

Aramco will acquire about 22.5% of refining and chemical firm PetroRabigh from the Japanese company, taking its stake to 60% and Sumitomo Chemical’s to 15%, according to a statement Wednesday.

The shares will change hands at 7 Saudi riyals apiece. PetroRabigh’s shares closed at 7.40 riyals on Tuesday in Riyadh.