Combining Geomechanics and Geophysics – a Need for Reservoir Seismic Monitoring

A-8 COMBINING GEOMECHANICS AND GEOPHYSICS – A NEED FOR RESERVOIR SEISMIC MONITORING S. VIDAL¹ P. LONGUEMARE² F. HUGUET¹ P. MECHLER³ ¹Gaz de France PO Box 33 93211 Saint Denis la Plaine France ²Institut Français du Pétrole ³Paris VI University Abstract 1 The seismic surveillance of producing reservoirs is a key to meeting goals of reduced operating costs and maximised recovery. Changes in fluid saturation pore pressure and stresses that occur during production induces changes in the reservoir density and compressibility that may be detected by seismic methods. The influence of mean effective stresses due to changes in mean total stresses