Integrating 4D Seismic and Geomechanics – A Case Study

A038 Integrating 4D seismic and geomechanics: a case study Abstract 1 Time-lapse (4D) seismic effects have been studied in a depleting gas field. Feasibility studies based on velocitystress relationships derived from core data suggest that large changes in seismic traveltimes may be expected. However our observations from the actual 4D seismic indicate that these effects are significantly smaller than modeled. At the same time timeshifts outside the reservoir zone are observed. These are considered due to geomechanical effects. Geomechanical models of depleting reservoirs predict that as a result of reservoir compaction due to pressure depletion changes in the long-wavelength stress