Method for the exploitation of a sedimentary basin carried out by computer, said sedimentary basin comprising at least one sedimentary layer and having at least one well passing through it, in which the following are known: the value of content of organic carbon TOC A and the value of the hydrogen index IH A at the current time at at least one well, a map of bathymetry and a map of rate of sedimentation of said sedimentary layer, characterized in that the following stages are carried out: a) for at least one sedimentary layer, maps of content of organic carbon TOC 0 and of hydrogen index IH 0 at the time of the deposition of said sedimentary layer are constructed starting from said values of content of organic carbon TOC A and of hydrogen index IH A at the current time at said well, and by means of said maps of bathymetry and of rate of sedimentation of said sedimentary layer, by means of the following stages: i) models of content or organic carbon TOC 0 and of hydrogen index IH 0 at any point of said sedimentary layer at the time of the deposition of said sedimentary layer are constructed, said models connecting said content of organic carbon TOC 0 and said hydrogen index IH 0 at any point of said sedimentary layer at the time of the deposition of said sedimentary layer with said maps of bathymetry and of rate of sedimentation of said sedimentary layer and with chemical and biological parameters of said sedimentary layer; ii) said models are adjusted by determining said chemical and biological parameters by means of said current values of content of organic carbon TOC A and the value of the hydrogen index IH A at said well; and iii) said maps of content of organic carbon TOC 0 and of hydrogen index IH 0 at the time of the deposition of said sedimentary layer are constructed by applying said adjusted models in every grid cell of said sedimentary layer by means of the chemical and biological parameters determined and said maps of rate of sedimentation and of bathymetry; b) at least one zone of said sedimentary basin comprising hydrocarbons is determined by means of said maps of content of organic carbon TOC 0 and of hydrogen index IH 0 at the time of the deposition of said sedimentary layer; and c) said zone of said sedimentary basin is exploited by carrying out exploratory or exploitation drillings in said at least one determined zone. a) for at least one sedimentary layer, maps of content of organic carbon TOC 0 and of hydrogen index IH 0 at the time of the deposition of said sedimentary layer are constructed starting from said values of content of organic carbon TOC A and of hydrogen index IH A at the current time at said well, and by means of said maps of bathymetry and of rate of sedimentation of said sedimentary layer, by means of the following stages: i) models of content or organic carbon TOC 0 and of hydrogen index IH 0 at any point of said sedimentary layer at the time of the deposition of said sedimentary layer are constructed, said models connecting said content of organic carbon TOC 0 and said hydrogen index IH 0 at any point of said sedimentary layer at the time of the deposition of said sedimentary layer with said maps of bathymetry and of rate of sedimentation of said sedimentary layer and with chemical and biological parameters of said sedimentary layer; ii) said models are adjusted by determining said chemical and biological parameters by means of said current values of content of organic carbon TOC A and the value of the hydrogen index IH A at said well; and iii) said maps of content of organic carbon TOC 0 and of hydrogen index IH 0 at the time of the deposition of said sedimentary layer are constructed by applying said adjusted models in every grid cell of said sedimentary layer by means of the chemical and biological parameters determined and said maps of rate of sedimentation and of bathymetry; i) models of content or organic carbon TOC 0 and of hydrogen index IH 0 at any point of said sedimentary layer at the time of the deposition of said sedimentary layer are constructed, said models connecting said content of organic carbon TOC 0 and said hydrogen index IH 0 at any point of said sedimentary layer at the time of the deposition of said sedimentary layer with said maps of bathymetry and of rate of sedimentation of said sedimentary layer and with chemical and biological parameters of said sedimentary layer; ii) said models are adjusted by determining said chemical and biological parameters by means of said current values of content of organic carbon TOC A and the value of the hydrogen index IH A at said well; and iii) said maps of content of organic carbon TOC 0 and of hydrogen index IH 0 at the time of the deposition of said sedimentary layer are constructed by applying said adjusted models in every grid cell of said sedimentary layer by means of the chemical and biological parameters determined and said maps of rate of sedimentation and of bathymetry; b) at least one zone of said sedimentary basin comprising hydrocarbons is determined by means of said maps of content of organic carbon TOC 0 and of hydrogen index IH 0 at the time of the deposition of said sedimentary layer; and c) said zone of said sedimentary basin is exploited by carrying out exploratory or exploitation drillings in said at least one determined zone.