mehdi amiri - South Zagross Oil and Gas Production Company / ICOFC / NIOC, Shiraz, Iran
Jamshid Moghadasi - Department of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran
mohammad Jamialahmadi - Department of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran
Mohammad Najafi - South Zagross Oil and Gas Production Company / ICOFC / NIOC, Shiraz, Iran

Enhanced oil recovery methods are used to recover the percents of oil which are not naturally recoverable from reservoirs. Water injection as a secondary recovery is used to maintain thepressure in water-drive reservoirs. An important point for having a successful injection is the compatibility of injection and formation waters.This paper presents the predicting of calcium sulfate scale tendency of formation water, injectionwater and mixing of injection water with formation water at different temperatures. Theexperimentally measured chemical analyses of formation water and injection water were used byOLI ScaleChem software to determine the tendency of scale formation. This software has been applied to investigate the potential of calcium sulfate scale tendency in Iranian oilfields, as a method of secondary recovery or reservoir pressure maintenance.

Scale tendency; CaSO4; Temperature; Iranian oilfield; Water injection