Under the terms of the contract, Stone & Webster will carry out engineering studies to determine the optimum configuration for each cracker's capacity expansion. The study will be completed by autumn, after which the findings will be presented to Saudi Basic Industries Corporation (Sabic), Petrokemya's parent company, which will determine how to proceed.

Unit 1 has a current nameplate capacity of 800,000 tonnes a year (t/y). It was originally built in the early 1980s by Japan's Mitsui & Company, and utilises Brown & Root proprietary technology. Unit 3 has a nameplate capacity of 800,000 t/y. Also built by Mitsui, it utilises Stone & Webster downstream technology.Petrokemya is also developing a new vinyl complex in Jubail, for which the tender for the front-end engineering and design and project management services contract is expected soon (MEED 12:5:06).