LONDON, ALMATY, MOSCOW (Reuters) — Major European trader Vitol is set to increase its cash-for-oil deal with Kazakhstan’s state energy firm by offering about $650 mln or more to finance the Kashagan oilfield, sources familiar with the matter said.

Reported by Reuters, one industry source said the deal was worth $650 mln and could be signed as early as next week. Three other banking and industry sources said the deal could be worth up to $750 mln and would be signed soon, without giving a specific date. The additional funds will bring Vitol’s prepayment for Kashagan to about $2.25 bln.

Vitol initially won a tender in 2016 to provide $1 bln to cover KMG’s share in the Kashagan field in exchange for crude cargoes. The loan, syndicated between various international banks, was increased by $600 mln in September.

Privately-held Vitol has been the dominant player in Kazakh oil exports for more than a decade, taking barrels mainly to Russian ports and shipping them to European refineries. The trader first signed a prepayment deal with KMG in 2015 for oil from Tengiz, Kazakhstan’s largest producing field. Vitol offered $3 bln in that deal.