4-D seismic reservoir simulation in a south timbalier 295 turbidite reservoir, gulf of Mexico

Abstract

4-D seismic reservoir simulation combines the analysis of 4-D (time-lapse) seismic changes measured in an oil and gas field with 3D elastic seismic modeling, reservoir characterization and fluid flow simulation to better understand drainage patterns of oil, gas and water into wells and to identify bypassed pay. We have solved this poorly constrained, inverse problem and arrived at a self-consistent reservoir simulation that minimizes error and predicts 4-D seismic changes similar in space, time, and magnitude to those observed in a complex, intertwined, turbidite channel reservoir in the South Timbalier 295 field, Gulf of Mexico. Particle flow produced from the seismic reservoir simulation predicts that drainage was complex, with a pressure drop in the reservoir to below the bubble point producing a gas cap nearby the producing wells. Brightened seismic amplitudes both downdip and updip of the wells indicate that the gas coming out of solution filled the most permeable of the tubular turbidite channels. Poor oil migration downdip suggests the need for water injection, which the operator instituted in 1997 to recover this downdip oil and repressurize the reservoir. Additional production drilling must be placed precisely to target the tubular turbidite channels not filled with gas. The seismic reservoir simulation suggests that this enhanced recovery strategy should be successful. As we get better and better at 4-D seismic reservoir simulation, we should get more and more of the original oil-in-place from complex reservoirs.