Closing the Loop via Scenario Modeling in a Time-Lapse Study of an EOR Target in Oman

At an EOR field in South Oman an extensive synthetic modeling study was done in order understand steam flow behaviour within the reservoir. To understand the permeability distribution within the steam flooded zone, a simulated “Close-the-Loop” workflow was executed based on scenario modeling that relates changes in acoustic properties (velocity and density) with those in reservoir properties such as oil saturation, temperature, permeability. Time-lapse zero-offset synthetic seismic were generated from a “Reference” reservoir model representing the ground truth. This synthetic seismic was used as “data” in the CtL workflow. The “Reference” model obeys all in-situ measurements including temperature logs from the observation wells. We also created a set of scenarios i.e., variances of the “Reference” reservoir model in terms of permeability distribution. Time-lapse synthetic seismic corresponding to each of the scenarios were compared with the data, in a time-lapse sense, to select a scenario most similar to the “Reference” reservoir model. We used three approaches to compare scenario synthetics with the data: (1) similarity attribute, (2) difference of maps, and (3) difference of energy, to select the scenario that best fits the data. Seismic quantification of the match between these scenarios and the “Reference” reservoir model helped identify the scenario whose permeability distribution matches with that of the “Reference” model, in the zone of interest, and hence, Close the Loop.