Development of Reservoir Descriptions To Aid in Design of EOR Projects

ABSTRACT A new technique was developed to obtain reservoir descriptions to aid in the design of enhanced oil recovery (EOR) projects. This technique incorporates the reservoir performance during primary and secondary processes as well as the geological and petrophysical data. The advantage of this technique over statistical techniques is that a more realistic reservoir description can be obtained. The reservoir description when used with an EOR reservoir simulator would yield a more realistic prediction of EOR performance and minimize the risk in an EOR field project. This technique may also be used to validate a reservoir simulator for field scale EOR performance. If the reservoir description is derived independent of EOR performance, the reservoir description is based only on the reservoir heterogeneities. The EOR process variables can then be quantified from the EOR performance without changing the reservoir description (Ader and Stein1). The application of this technique is illustrated for a 250 acre area of interest in a San Andres formation reservoir. The initial reservoir description is formulated based on permeability to porosity ratio plots, injection and production profiles, core data, and pressure transient tests. The initial gas saturations and pressures are obtained based on dimensionless performance curves. The reservoir description is then refined by history matching primary and secondary performance for individual wells using a reservoir simulator. For the example discussed in this paper, an excellent match of performance was achieved using this technique.