Recovery method for evolutionary process of porosity of clay shale rich in organic matter

The invention discloses a recovery method for an evolutionary process of the porosity of a clay shale rich in an organic matter. The recovery method comprises the steps of sampling in a target layer of a target work area to obtain multiple samples, and acquiring a group of actually measured data respectively corresponding to each sample, and stress field distribution data of the target layer; obtaining a first relational expression and a second relational expression according to the actually measured data; establishing a first mathematical model of hydrocarbon porosity on maturity according tothe first relational expression and the second relational expression; establishing a second mathematical model of the porosity on a tectonic stress according to the second relational expression and the stress field distribution data; and determining a numerical value of the porosity of each geologic observation spot in the target layer in each historical period of geological evolution according to the first mathematical