Oilfield services firm Petrofac was the best performing FTSE 100 stock on Monday morning after the company bagged a lucrative contract in the United Arab Emirates (UAE).The government of Sharjah has appointed Petrofac to take over operational responsibility and facilities management of the Sajaa Gas Plant and related assets, located some 30 kilometres from the commercial centre of Sharjah.The five year contract is worth in excess of $250m.By the end of 2010 Petrofac will start providing a full range of facilities management services to the Sharjah government including: reservoir management, drilling and well services, plant operations and engineering and project management."Our focus will be on a safe and effective transition, and asset performance and integrity," pledged Bill Dunnett, managing director of Petrofac's offshore engineering and operations business unit.The government of Sharjah owns a 60% participating interest in the Sharjah gas and associated liquids concession, with BP currently owning the remainder. The concession will expire in November 2013 at which point the BP-operated facilities will be transferred to the government.