A pilot area in the East Vacuum Grayburg-San Anders Unit (EVGSAU) was selected for a comprehensive evaluation of the use of foam for improving the effectiveness of a CO flood. The response from the foam field trial was very positive, it successfully demonstrated that field application of CO-foam is a technical viable process for improved oil recovery (IOR). A pseudo-miscible reservoir simulator, MASTER, which was recently modified by incorporating a newly developed foam model, was used to conduct a history match study on the pilot area at EVGSAU to understand the process mechanisms and sensitive parameters. The ultimate purpose was to establish a foam predictive model for CO- foam processes.
In this paper, the history match results are presented. The important modeling considerations that led to an acceptable history match are highlighted and discussed. Finally, the simulated results of a foam predictive ease are presented. The injection schedule of the foam predictive ease was specifically selected to mimic the filed injection schedule used in the foam pilot test at EVGSAU.
The simulated results are consistent with the field pilot test results. Overall, the foam model is found to be adequate for field scale CO-foam simulation. The results also confirm that the communication path between the foam injection well and the offending well had a strong impact on the production performance.