Method of characterising a subsurface volume

A method of characterizing a subsurface discretized volume comprising a plurality of cells, the method comprising extracting a geobody from seismic data arranged within the discretized volume, the geobody comprising a subset of the plurality of cells, each cell of the subset having one or more properties indicative of a particular fluid phase, wherein the extracting comprises:

• determining a propagation probability value for each cell indicative of the probability that a front propagates through the cell;
• beginning from a source within the discretized volume, using the propagation probability value to calculate a traveltime for each cell, the traveltime describing the time the front takes to travel from the source point to the cell;
• using the traveltimes to extract the one or more properties indicative of a particular fluid phase of the geobody from the seismic data;
• and
• using the extracted one or more properties indicative of a particular fluid phase of the geobody to aid hydrocarbon recovery from a reservoir comprising the discretized volume by:
• monitoring whether the volume and geometry of the geobody corresponds to a planned geobody volume and planned geometry relating to a volume of an injection fluid injected during the hydrocarbon recovery;
• and
• modifying an injection strategy used in the hydrocarbon recovery if the geometry of the geobody does not correspond to the planned volume and geometry, wherein the modifying the injection strategy includes at least one of modifying where the injection fluid is injected, the injection fluid used, the temperature of the injection fluid, and the pressure of the injection fluid.