Integration of Reservoir Simulation and Time-Lapse Seismic in Delhi Field: A Continuous CO₂ Injection EOR Project

In assessing the effectiveness of any CO₂ enhanced oil recovery projects, it is essential to track the flow path of injected CO₂ and determine the bypassed oil pockets. The objective of this research was to construct a high definition, dynamic reservoir model that can support reservoir management activity. Time lapse seismic is an effective tool for monitoring CO2 movement and deciphering flow channels in the reservoir. Reservoir engineers use mathematical simulation, which is constrained by production-injection data, to determine displacement efficiency and dynamic changes in pressure and saturation in the reservoir. Reservoir simulation also serves as a prediction tool to evaluate the economics of the CO2 projects. Both time-lapse seismic analysis and reservoir simulation can complement each other to increase the resolution of CO₂ flow path and CO₂ – effectiveness.

The paper presents integration of geology, geophysics and engineering for assessing a continuous CO₂ injection EOR project in Delhi Field, Louisiana. The CO₂-targeted formations are Tuscaloosa and Paluxy sandstones. The production and injection activities in Delhi Field result in changes in fluid saturations and pore pressure. These changes affect properties of the reservoir rock and fluids, which can be detected by time-lapse seismic analysis as P-wave anomalies. A geologic model was built using well logs, petrophysical measurements and seismic inversion for the Reservoir Characterization Project (RCP) area. We built two reservoir simulation models, including black oil and an eleven-component compositional model, based on the reservoir geologic model as the first step in the integrated research effort. We obtained production history matches for the primary, secondary and tertiary phases of the field operation.

The simulated flow paths of the injected CO₂ agree well with the time-lapse seismic interpretations. This agreement validates the effectiveness of integrating geologic modeling, reservoir simulation, and time-lapse seismic analysis in assisting field operations and maximizing oil recovery efficiency.