Saudi Aramco, the world’s leading integrated energy and petrochemicals enterprise, and PT Pertamina, Indonesia’s state oil and gas company, signed a Joint Venture Development Agreement (JVDA) to jointly own, upgrade and operate the Cilacap Refinery in central Java, Indonesia, Al Arabiya English reported.

The $5b agreement was signed between Saudi Aramco’s President and CEO, Amin Al-Nasser, and Pertamina’s President Dwi Soetjipto at the Pertamina’s headquarters in Jakarta, according to Asharq Al-Awsat.

The two companies will establish a joint venture for the project, in which Pertamina will own a 55% stake. The upgrade will increase the refinery’s capacity from 348,000b/d to 400,000b/d. Saudi Aramco will supply most of the crude oil for the refinery. The company said that it has completed the design phase, adding that the main architectural designs would be ready in the first quarter of 2017. The project is scheduled to be completed in 2021.

The Cilacap refinery is part of Pertamina’s Refinery Development Master Plan (RDMP) and is designed to process Arabian crude supplied by Saudi Aramco. It will also produce refined products that meet Euro V specifications, basic petrochemicals, and Group II base oil for lubricants. In addition, the partnership between Pertamina and Saudi Aramco will enhance the competitiveness of Indonesia’s refineries and contribute to improved energy security.