Evaluation method and system for identifying heavy oil water flooded layer through neutron gamma

The invention discloses an evaluation method and system for identifying a heavy oil water flooded layer through neutron gamma, the method takes a neutron gamma curve and a resistivity value as the judgment basis for judging the water flooded layer, the neutron gamma curve is the preliminary judgment standard, and the resistivity value is the further and finer judgment basis. According to the evaluation method, the change rule of a neutron gamma curve after the heavy oil reservoir is flooded is found, the heavy oil reservoir structure is combined, the reason for neutron gamma change is researched from the nuclear physical logging principle, and therefore the interpretation method for judging heavy oil flooding through neutron gamma logging is formed. The neutron gamma logging can be implemented in a cased well, so that the neutron gamma curve is measured in a new well after well cementation, the neutron gamma curve of a production well is measured again after a certain production cycle, and the heavy oil flood