The invention is a method of monitoring an underground formation into which a gas is injected or from which a gas is produced, by a stratigraphic inversion of seismic data with anamorphosis of impedances. Pre-injection and post-injection seismic data are acquired. A pre-injection seismic impedance cube IP1 is determined by a stratigraphic inversion of the pre-injection seismic data. An anamorphosis function α is defined by a function comprising a positive lower limit B1, an upper limit B4, an identity interval defined between limits B2 and B3, with B1B2B3B4. A value for each limit B1, B2, B3 and B4 is associated with each cell of the cube. Post-injection seismic impedances IP2 are determined by a stratigraphic inversion of the post-injection seismic data wherein the anamorphosis function α is applied to seismic impedances IP2. The gas is located within the zone by identifying the cells where IP2IP1. 展开▼
