Method for exploiting for hydrocarbons within a sedimentary basin, said basin resulting in particular from the deposition of inorganic sediments and of terrestrial organic matter, said method being implemented on the basis of measurements of properties relating to these deposits and to the hydrology of said basin, by means of a stratigraphic simulator running, on a computer, a stratigraphic model for a succession of time intervals, characterized in that, for at least one time interval: A. by means of said simulator and parameters of said simulator for said time interval, said parameters of said simulator being constructed on the basis of said measurements, a mesh representation representative at least of the distribution of said inorganic sediments within said basin for said time interval is determined; B. by means of a hydrological model and parameters of said hydrological model, said parameters of said hydrological model being constructed on the basis of said measurements and of said mesh representation, at least one unsaturated zone is delimited within said basin, said unsaturated zone corresponding to the vadose zone of said basin; C. by means of a model of the accumulation of said organic matter and of parameters of said accumulation model, said parameters of said accumulation model comprising the thickness of said unsaturated zone in said time interval, the stability of said thickness of said unsaturated zone over said time interval, and the surface water flow in said time interval, said thickness of said unsaturated zone being stable if the following equation is satisfied: Su = SR + SL where SL is a rate of eustatic change, SR is a rate of sedimentation relative to the deposition of said organic and inorganic sediments, and Su is a rate of subsidence, at least one zone of accumulation of said terrestrial organic matter within said basin and an amount of terrestrial organic matter accumulated in said accumulation zone are determined; and in that, on the basis of said amount of terrestrial organic matter accumulated and of said mesh representation, the petroleum potential of said basin is quantified, an exploration plan for said basin is defined, and said basin is exploited according to said plan. A. by means of said simulator and parameters of said simulator for said time interval, said parameters of said simulator being constructed on the basis of said measurements, a mesh representation representative at least of the distribution of said inorganic sediments within said basin for said time interval is determined; B. by means of a hydrological model and parameters of said hydrological model, said parameters of said hydrological model being constructed on the basis of said measurements and of said mesh representation, at least one unsaturated zone is delimited within said basin, said unsaturated zone corresponding to the vadose zone of said basin; C. by means of a model of the accumulation of said organic matter and of parameters of said accumulation model, said parameters of said accumulation model comprising the thickness of said unsaturated zone in said time interval, the stability of said thickness of said unsaturated zone over said time interval, and the surface water flow in said time interval, said thickness of said unsaturated zone being stable if the following equation is satisfied: Su = SR + SL where SL is a rate of eustatic change, SR is a rate of sedimentation relative to the deposition of said organic and inorganic sediments, and Su is a rate of subsidence, at least one zone of accumulation of said terrestrial organic matter within said basin and an amount of terrestrial organic matter accumulated in said accumulation zone are determined;