Time-Lapse Depletion Modeling Sensitivity Study: Gas-Filled Gulf of Mexico Reservoir

• Main Author: Gautre, Christy
• Format: Others
• Published: ScholarWorks@UNO 2010
• Subjects: gas; oil; reservoir; time-lapse seismic; rock physics modeling; depletion; water flood; production; Gulf of Mexico; 4D
• Online Access: http://scholarworks.uno.edu/td/1187; http://scholarworks.uno.edu/cgi/viewcontent.cgi?article=2170&context=td

Time-lapse seismic allows oil/gas reservoir monitoring during production, highlighting compaction and water movement. Time-lapse modeling, using a stress-dependent rock physics model, helps determine the need and frequency of expensive repeat seismic acquisition. We simulate a Gulf of Mexico gas reservoir time-lapse response for depletion and water flooding using uncertainty ranges in water saturation, porosity, stress-induced velocity changes, and pore compressibility. An analysis is conducted to see if a water-swept region could have been predicted. Findings show the swept and un-swept monitor cases amplitude differences range from 6% to 15%, which is higher than the actual monitor seismic noise level. Thus, it is unlikely these cases could be differentiated. However, the modeled amplitude changes from base to monitor cases do not match measured amplitude changes. This suggests the rock property model requires pressure-variance improvement and/or the changes in seismic amplitudes are associated with pressure/porosity, thickness, or saturation cases not modeled.