Abstract: Daniudi gas field lied in the north of Ordos basin, owing to the factors such as reservoir heterogeneity, mud invasion, high and low degree of mineralization and enlarged borehole diameter, it is extremely difficult to identify fluid properties of carbonate rock in Daniudi gas field. Therefore, in accordance with existing data statistics and analysis, 7 methods have been adopted in gas and water layers identification and then the identification standards of reservoirs, gas layers, water layers and gas and water mixed layers have been established.