Exxon Mobil, Saudi's Aramco and Samref on Monday signed an agreement to evaluate a significant upgrade of the Samref refinery in Yanbu, and an expansion of the facility into an integrated petrochemical complex.

The companies intend to explore capital investments to upgrade and diversify production, including high-quality distillates that result in lower emissions and high-performance chemicals, Aramco said in a statement.

Earlier this year, the Saudi state oil giant had signed a memorandum of understanding with Exxon to evaluate an upgrade to the Samref refinery.

Samref is an equally owned joint venture between Aramco and Mobil Yanbu Refining Company, which is a wholly owned unit of Exxon.

(Reporting by Pooja Menon in Bengaluru; Editing by Leroy Leo and Shailesh Kuber)