Integration of seismic data with rock physics and reservoir modeling in the FRS project
Creators: name: Nowroozi Charandabi, Davood
Publisher: name: Graduate Studies
Year: 2017
Subjects: subject: Geophysics
subject: FOS: Earth and related environmental sciences
subject: CO2 injection
subject: Shallow target CO2 injection
subject: FRS project
subject: Alberta, Canada
subject: Reservoir Simulation
subject: Rock physics
subject: Seismic forward modeling
subject: RTM
subject: Time-lapse seismic
subject: 4D seismic study

description: This thesis is related to a CO2 injection project from the well logging to seismic modeling and imaging, so many disciplines are involved. The reservoir is at a shallow depth of 300 m, so it is at a low temperature and low-pressure state. A compositional method was used for the fluid flow simulation. The change of phase possible around the anticipated pressure and temperature for CO2 injection is another limitation for a compositional simulation, and it means lower density change after injection in the formation, so the gas phase injection was selected for the flow simulation modeling. The simulation results show that the plume diameter for bottom hole pressure equal to 4.9 MPa will be 185 m after 5-year injection. A mathematical routine was introduced for the long-term CO2 plume shape estimation as the compositional simulation is a time taking procedure. Also, the rock physics study shows that the CO2 injection will decrease the density of formation around 3% and the P-wave velocity between 7 and 15% based on the fluids mixed type. It can also affect the S-wave velocity up to 1%, and in the seismic studies, there is enough of a change in the S-wave velocity to consider PS and SS-wave data for the reservoir characterization. The rock physics equations solved for the pressure changes by the Equation of State for CO2 and for the brine and a set of curves related to the fluid mixed type were introduced. The seismic studies based on the rock physics models show that the fluids mix type is a determinative factor for interpretability of a reservoir. Seismic forward modeling was undertaken using both acoustic and elastic finite difference approaches, and imaging was done using reverse time migration. Acquisition configuration (well or surface seismic) influence was checked in the current research and results show a better amplitude change due to the reservoir activity in the well seismic data and a better imaging condition for surface seismic acquisition. For patchy or semi-patchy saturation, mixed with a linear (or near linear) converter, the saturation is calculated with an acceptable error by the acoustic, seismic response. In a parabolic converter as Reuss average in a fine mixed type, the time-lapse acoustic response is insufficient to identify saturation explicitly, and the results of the fluid flow simulation is another key to invert available data to the reservoir saturation. The final results show that the reservoir characterization and time-lapse study by seismic is an entirely non-deterministic and data from fluid flow simulation results of the reservoir can be a powerful component for a successful saturation inversion.