We perform a feasibility study on the likelihood of seismically detecting and interpreting the time-varying changes in a North Sea reservoir during solution-gas-drive oil production from a horizontal well. This study integrates reservoir engineering fluid-flow simulations, rock physics measurements and transformations, and prestack seismic modeling and migration on a real but anonymous North Sea reservoir model. Our hydrocarbon recovery monitoring analysis includes:
We calculate spatial distributions of reservoir rock properties from the fluid-flow simulation data, and map the associated seismic responses at three production-time snapshots: prior to any oil production (Base Survey), after 56 days (Monitor 1), and after 113 days (Monitor 2) of oil production. Multi-offset seismic surveys are simulated for each of these three production times. Using realistic seismic acquisition parameters, we are able to successfully detect and monitor dynamic gascap expansion in the reservoir during the fluid-flow simulation of the oil production process. Evidence of gas coning is clearly visible in the prestack-migrated difference sections at realistic seismic noise levels and frequency bandwidth.