I don't think we get £20m off Nexen for sleeve sponsorship. Pretty sure it's less than that. Could be £20m all told though as they have extensive advertising inside the ground plus they sponsor the bridge linking the CFA to the stadium.
Further to JP Rouve's post, here's a more extensive list of commercial partners. Plenty of non-UAE companies in this lot:
Aabar, Arabtec, Astra, Betsafe, Digicel, EA SPORTS, Etihad, Etisalat, First Gulf Bank, Hays, Healthpoint, Heineken, Jiwasraya, LG, Nexen, Nike, Nissan, Pak Lighting, PZ Cussons, QNET, SAP, SHB Bank, Soccerworld, Star Beer, TCA Abu Dhabi, Tecate, Tempobet, UBTECH, Veqta, Vitality, Wega, Wix, Whaley Technology, Wolf Blasts.