Abstract

Approximately 60-70% of the oil in place cannot be produced by conventional methods. Enhanced oil recovery phase of oil reservoirs production usually comes after the primary and secondary recovery through artificial lift and water or gas injection. Chemical EOR process are implemented to reduce the residual oil saturation by lowering the interfacial tension between oil and water and develop a favorable mobility ratio between displacing fluid and displaced fluid. The lowering of interfacial tension can be achieved by using alkali & surfactants that improves the oil displacement efficiency. Further the viscosity of the displacing fluid can be improved by using polymers which finally improves the volumetric sweep efficiency by developing a favorable mobility ratio between displacing fluid and displaced fluid. Viraj field which was discovered in year 1977 by ONGC ltd was found suitable for chemical EOR due to its viscous crude of viscosity of around 50 cp at reservoir condition (81o c) and medium API of 18.9o . After completion of a successful ASP pilot, the field-wide implementation of ASP was commissioned on July 19, 2019. This technical paper examines a case study covering the widespread application of ASP flooding and the challenges encountered in Viraj Field