Method for confirming fluid density and solid skeletal density

The invention provides a method for determining a fluid density and a solid skeletal density in a storage layer, and determining the fluid density and the solid skeletal density of a three dimensional area. The method for determining the fluid density in the storage layer comprises the steps of: collecting logging data aiming at the storage layer; obtaining storage layer density data rho i and porosity data phi i at each sampling point of n sampling points in the storage layer from the logging data aiming at the storage layer, wherein i = 1, 2, ..., n; and determining the fluid density rho f in the storage layer through a formula. Through the method provided by the invention, the fluid density and the solid skeletal density in the storage layer can be determined by using the density data and the porosity data of the storage layer obtained by the logging data; the fluid density and the solid skeletal density can be spread to the whole three dimensional data space through a nonlinear inversion method in combination with a three dimensional seismic data volume; and the three dimensional space data obtained through inversion can be used for storage layer forecasting, gas and water identification, oil and gas accumulation description and the like.