m.s karambeigi - IOR research institute national iranian oil company research &tech directorate,tehran iran
m zahedzadeh - IOR research institute national iranian oil company research &tech directorate,tehran iran
m radmehr - IOR research institute national iranian oil company research &tech directorate,tehran iran
e roayaee - IOR research institute national iranian oil company research &tech directorate,tehran iran

Mixing of incompatible injecting and formation waters is a common reason of mineral scale deposition in oil fields.Because of time consuming and costly experimental method,thermodynamic models are becoming widely used to assess the type and location of this type of scales. In this research, formation tendency of sulphate scales is predicted using a thermodynamic model (Oddo-Thomson model) during water flooding inone Iranian offshore oil field. Two water resource scenarios are candidates to study with the view of mitigating the scale deposition: sea water and produced water re-injection. Three types of sulphate scale including CaSO4, SrSO4, and MgSO4 are investigated in this study.Moreover, several full field simulation studies (brine tracking module) are used in conjunction with the above data to have better assessment the situation. The results show that there is very high likely to have the deposition of CaSO4 and SrSO4 scale, while the amount of MgSO4 formation is negligible. Finally, sea water injection was selected as a better candidate than produced water due to less formation damage, observed through study.

Keywords: Mineral scale,Water flooding. Oddo-Thomson model, Incompatibility of waters, Brine tracking,