Key Aspects Of Smart Water EOR In Chalk
S. Strand and T. Puntervold
Event name: 80th EAGE Conference and Exhibition 2018
Session: Modified Salinity Waterflooding in Chalk Reservoirs (Dedicated Session)
Publication date: 11 June 2018
Info: Extended abstract, PDF ( 511.19Kb )
Price: € 20
Waterflooding of oil reservoirs is an important technique to increase oil recovery from carbonate and clastic reservoirs. Understanding the wetting properties of oil reservoirs has been the fundament for research the last 15-20 years with the objective to optimize the oil recovery by wettability modification. The injected water, with a favourable ionic composition, can modify the reservoir wettability during production, and improve the displacement efficiency of oil. The EOR effect can be significant, especially in carbonate reservoirs. This paper gives a chemical review of the Smart Water EOR technique in carbonates, focusing on chalk. It is not obvious that Smart Water can be applied in any carbonate oil reservoirs. Therefore, detailed knowledge of the chemical mechanism for the wettability alteration process is crucial for field application. The results confirm that seawater is able to change the wettability towards more water-wet conditions, improving the oil recovery both in viscous flooding and spontaneous imbibition processes, and the efficiency increases with temperature. Key parameters affecting both the initial wettability and the wettability alteration process are documented. The results also describe how the ionic composition of seawater can be modified for improving the efficiency and lowering the temperature window for Smart Water EOR processes.