Abu Dhabi National Oil Co (ADNOC) said on Monday it had awarded two contracts to South Korea's Samsung Engineering worth more than $3.5 billion.

The contracts were signed by ADNOC Refining, a wholly owned subsidiary of ADNOC, and Samsung Engineering.

The first engineering, procurement and construction (EPC) contract was awarded for a $3.1 billion project on flexibility in crude oil processing, ADNOC said in a statement.

The crude flexibility project is scheduled to be completed by the end of 2022. It will enable the Ruwais Refinery-West plant to process up to 420,000 barrels per day of Upper Zakum crude, or similar oil grades, freeing up more exports of ADNOC's Murban crude, which is sold at a premium. urn:newsml:reuters.com:*:nL8N1PX4U8

The second EPC contract is for a $473 million project to recover power and water, also at the Ruwais oil refinery.

This project is scheduled to be completed by the end of 2023. It will generate an additional 230 megawatts of electricity for sale and 62,400 cubic metres of water daily by capturing waste heat and upgrading four gas turbines with closed-cycle power generation technology.

(Reporting by Rania El Gamal; Editing by Dale Hudson and Louise Heavens) ((rania.elgamal@thomsonreuters.com; +971 562 160 434; Reuters Messaging: rania.elgamal.reuters.com@reuters.net ; Twitter: https://twitter.com/Rania_ElGamal))