New Insights into the Application of a Magnetic Field to Enhance Oil Recovery from Oil-Wet Carbonate Reservoirs

Given recent moves towards cleaner energy production, the application of environmentally friendly methods for EOR is considered to be an important research strategy in increasing oil production from existing hydrocarbon reservoirs. Therefore, in this paper, the application of a magnetic field is introduced for the first time as a novel and eco-friendly EOR technique for oil-wet carbonate reservoirs.
The magnetic field is generated using three different magnet strengths of 3000, 4100 and 6000 Gauss (G). The impact of incremental increases in magnetic field on oil production from Austin chalk is investigated through measurements of contact angle, rock compaction and the spontaneous imbibition of water and the monitoring of rock surface streaming potential.
Dynamic contact angle measurements on oil-wet chalk surfaces in the presence of a magnetic field show that the value of contact angle is reduced faster than when a magnetic field is absent, indicating a significant increase in water imbibition into rock pores. The results of spontaneous imbibition tests reveal significantly greater oil production during the imbibition process in the presence of a magnetic field at about 8.5 times that from oil-wet chalk.
Monitoring of the streaming potential of the oil-wet rock surface in the presence and absence of a magnetic field indicates that a change in surface potential charge is responsible for the change in wettability of the surface from oil-wet to water-wet, hence improving water imbibition into carbonate rock which, in turn, can improve the oil displacement from pores.