Recent research findings suggest that wettability modification holds a great potential for increased oil production from mixed-wet and fractured carbonates. Our current knowledge of the field-scale performance of these processes is very limited despite very favorable results obtained in the laboratory-scale experiments. Reservoir simulation is required to properly scale up the process from laboratory to field conditions and to understand and interpret reservoir data. Without a mechanistic simulation tool and adequate scale up, it is unlikely that a cost-effective process can be developed and applied economically. The predictive simulation and methodology to scale up such a complex process will reduce the risk of failure of field projects.

A chemical compositional reservoir simulator with the capability to model oil recovery from mixed-wet carbonate rocks in both static imbibition and dynamic fractured block experiments using chemicals to alter wettability is used for this scale up study. The simulator captured the key recovery processes of capillary and natural imbibition, wettability alteration, buoyancy, oil mobilization, and viscous pressure gradient in imbibition experiments.

Proper scaling from laboratory to field indicates that the synergy of wettability alteration, ultra low interfacial tension, and emulsification under small viscous pressure gradient provides an attractive and profitable opportunity in fractured carbonate reservoirs. Dimensionless scaling groups and numerical simulations are presented for each experimental condition to aid in understanding the time dependence and up-scaling of the laboratory results to field scale applications.

The oil recovery results of the static imbibition experiment were successfully scaled using a reference time based on gravity emphasizing that the buoyancy was a dominant mechanism in this case. The scale up simulations for the dynamic fractured block experiment indicated favorable conditions for field scale applications with more dominance of viscous forces.

You can access this article if you purchase or spend a download.