Abstract:

Seismic history matching involves the use of time-lapse seismic data to match and predict the flow behavior of the reservoir. Time lapse seismic interpretation has evolved as an important diagnostic tool in efficient reservoir characterization and monitoring. Time lapse seismic modeling is an important step in a closed loop history matching where we match flow response as well as time lapse seismic response. The changes in seismic velocities are attributed to changes in saturation and pore pressure, and these velocity changes can be modeled using Gassmann’s equations. In this thesis, I explore how uncertainties in mechanical rock properties, specifically rock pore compressibility, can affect the production-related changes in seismic velocities. Reservoir rocks are described by at least four inter-related compressibilities, one of which affects the flow while the other impacts the wave velocities. At first using the Stanford VI synthetic reservoir I show how uncertainties in pore compressibilities can lead to uncertainties in the time-lapse seismic response. Then I extended this idea to a real field where pore compressibilities have been derived from well logs. Using data from Norne field, I have made a rock physics model for elastic properties of different formations. I have presented examples of sensitivity analyses on rock pore compressibility using flow simulation and velocity modeling based on the Norne field dataset. The analyses shows how uncertainties and natural variability in rock pore compressibility, when not accounted for in the flow simulation, can cause pitfalls in modeling of seismic velocities and associated time lapse seismic signatures.

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Copyright 2009, Amit Suman: Please note that the reports and theses are copyright to their original authors. Authors have given written permission for their work to be made available here. Readers who download reports from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the author, Amit Suman.