Ideally the performance of an EOR method is measured by macroscopic and microscopic displacement efficiency. For macroscopic displacement, the key factor is a mobility ratio between injected fluid and oil less than 1. The parameters related to this will depend on the type of EOR implemented. In miscible processes such as CO2 injection, this is achieved for higher gas viscosity or in the case of CO2 WAG or SWAG, lower relative permeability of the mixture. However, too much water may be detrimental to microscopic displacement. The microscopic displacement is related to interfacial tension and capillary pressure, which will affect the residual oil saturation.

In my research topic, I am running reservoir simulations to calculate mineral dissolution and precipitation in carbonate reservoirs during CO2 WAG injection. When CO2 is injected calcite dissolution happens near the injector and the pH decreases while precipitation occurs downstream. This change in porosity will affect the permeability in long term and may interfere in EOR performance, but I am still investigating this.

The main technical parameters affected EOR technologies are: Temperature, salinity/hardness of water, viscosity of oil, and permeability. 

   Dear Abdullah

 The most important parameters are initial wetabbility system, relative permeability and porosity. EOR is mostly focused on wetaability alternation in order to increase sweep efficiency of petroleum. Wetaability alternation will effect on remained oil and water saturation, relative permeability and finally overall production rate. The best indicator is measuring relative permeability and  wetaability by SCAL test.

Lots of good thoughts in the answers, no doubts. Thinking as a geologist, I would highlight that the displacement efficiency depends on many factors but, without a good geologic control, many of the responses we see in the field are going to be poorly understood. 

Remember that reservoir properties and the facies distribution, connection and continuity between reservoir bodies (one depending on the depositional setting, other depending of the direction of observation), degree of depositional heterogeneity, impact of the diagenesis (positive or negative), faults (seismic and sub-seismic compartments), presence of stratigraphic and depositional surfaces (some are important as flow baffles but some may be neglected during the upscaling and transition to the dynamic model) are all key static elements or components that will surely impact the understanding of the fluid flow inside the container during an EOR or IOR project. So, going to the engineer side, a flow unit must incorporate all the elements defined/interpreted by the geologist in the static model. And, of course, all the other dynamic aspects that were mentioned in the previous answers are equally important. Bottom line: A huge advantage is when geologists and engineers can understand each other, knowing how to deal with the limitations of their "scientific" method. Cheers, JD

Abdulmajeed,

For lab experimental work or field case studies, you can use the Design of Experiments (DOE) approaches to determine the most influential factors affecting the EOR process. In DOE, you will be able to obtain many levels for each factors, generate experiments, then calculate the response value either from experiments or simulation. After that, you fit a statistical model to find out the most influential factors affecting the process and see which factor is more influential than other.

This is a systematic procedure for finding he most influential factors affecting the EOR processes.

Please refer the book by Ganesh Thakur on Integrated Reservoir managements. This documents the screening guides for various EOR techniques.