Process for defining the locations of a plurality of wells (10, 12) in a field, the process being carried out by an electronic location defining system and comprising the following steps: - acquiring a geocellular model of the field, the model defining a plurality of cells, each cell being provided with fluid properties including at least a fluid density property and at least a fluid flow property for at least two fluid phases; - selecting a group of potential cells able to become a well location; characterized by positioning wells (10, 12) one after another in the group of potential cells, each positioning of a well (10, 12) comprising: * calculating for each cell of the group of potential cells, at least one fluid property insertion point driver (DFP1, DFP2) representative of a fluid property maximization, the fluid property insertion point driver (DFP1, DFP2) being calculated based on a window average of the fluid property taken around the cell; * calculating for each cell of the group of potential cells, at least one maximized distance insertion point driver (DMD1, DMD2, DMD3) representative of a maximization of a distance to another cell or group of cells having at least an undesired property, the undesired property being chosen among a cell containing a fluid phase which production from or injection into is not desired or a cell containing a well of the same type that the well (10, 12) being positioned, the at least one maximized distance insertion point driver (DMD1, DMD2, DMD3) being calculated for each cell based on a diffusive time of flight from the cell to the cell or group of cells having undesired properties; * calculating for each cell of the group of potential cells a combined insertion point driver (DCOMB) based on the at least one fluid property insertion point driver (DFP1, DFP2) and the at least one maximized distance insertion point driver (DMD1, DMD2); * defining a well insertion point of the well (10, 12) being positioned at the cell having a maximal combined insertion point driver (DCOMB). - acquiring a geocellular model of the field, the model defining a plurality of cells, each cell being provided with fluid properties including at least a fluid density property and at least a fluid flow property for at least two fluid phases; - selecting a group of potential cells able to become a well location; * calculating for each cell of the group of potential cells, at least one fluid property insertion point driver (DFP1, DFP2) representative of a fluid property maximization, the fluid property insertion point driver (DFP1, DFP2) being calculated based on a window average of the fluid property taken around the cell; * calculating for each cell of the group of potential cells, at least one maximized distance insertion point driver (DMD1, DMD2, DMD3) representative of a maximization of a distance to another cell or group of cells having at least an undesired property, the undesired property being chosen among a cell containing a fluid phase which production from or injection into is not desired or a cell containing a well of the same type that the well (10, 12) being positioned, the at least one maximized distance insertion point driver (DMD1, DMD2, DMD3) being calculated for each cell based on a diffusive time of flight from the cell to the cell or group of cells having undesired properties; * calculating for each cell of the group of potential cells a combined insertion point driver (DCOMB) based on the at least one fluid property insertion point driver (DFP1, DFP2) and the at least one maximized distance insertion point driver (DMD1, DMD2); * defining a well insertion point of the well (10, 12) being positioned at the cell having a maximal combined insertion point driver (DCOMB). * calculating for each cell of the group of potential cells a combined insertion point driver (DCOMB) based on the at least one fluid property insertion point driver (DFP1, DFP2) and the at least one maximized distance insertion point driver (DMD1, DMD2); * defining a well insertion point of the well (10, 12) being positioned at the cell having a maximal combined insertion point driver (DCOMB).