Abstract: The Sebei-2 Gas Field is a big biogenic gas field in Qaidam Basin. In this gas field，there exist loose rock，multiple
thin gas layers，edge water and complex gas-water distribution. In the process of gas field production，it is common that gas
wells produce water，the amounts of water produced from gas wells vary in a wide range，and the outputs of gas wells decline
fast. A clear understanding of the features of gas wells producing water ensures the stable production of gas field. Based on
production data，the features of gas wells producing water and ratio of rising water-gas ratio rising in gas wells and groups are
carefully studied. Water-producers are thus classified into four types according to the water sources and water amount produced.
The types of water encroachment in different groups in this field are identified based on the calculation of aquifer influx and
water influx rate. At last，the location of the water-encroachment front in different groups can be effectively identified with the
aid of the distribution of the in-place cumulative water percentage of each group.

Key words: Sebei-2 Gas Field, water-producing type, aquifer influx, water influx rate, in-place cumulative water percentage