Abstract: The formation water distribution of Mawu No.1 reservoir in Jingbian area, Changqing gas field, is of completely different characteristics from common oil/gas reservoirs due to non-edge water and non-bottom water and is different from those of gas and water in fracture-cavity system. The regional"relative water-rich area” is formed mainly by the effects of regional structure and reservoir heterogeneity. According to the well log, separate zone testing and gas test data and using conventional well log discriminant method and polynomial self- network approach, producing water zone discriminant standard and gas zone,gas-bearing bed and dry sand as well as gas-water layer discriminants and conditions are given respectively. The coincidence rate of commercial gas zones reaches 97%.

Key words: Fluid component, Decision, Polynomial, Network, Method, Changqing gas field