Theoretical study, reported in this paper, qualifies unique mechanisms of water coning in gas wells. Water coning in gas wells has been understood as a phenomenon similar to that in the oil wells. It is shown, however that both the water inflow mechanism and its impact on well's productivity are substantially different. It is shown, for example, that, after water breakthrough, the oil-water interface at the well's completion would continue to cone, while the gas-water interface reverses at the top of the cone.
Analyzed in the paper are the results of a conventional simulation of water coning in gas wells showing that water could affect productivity only at the very late stage of well's life. However, field data, shown in the paper, evidence early and severe water problems. This contradiction is explained in the paper by including the effects of Non-Darcy flow, perforation density and the ratio of vertical-to-horizontal permeability in modeling of water coning in gas wells. Results from numerical simulation combined with analytical models show that an early water breakthrough and a considerable increase in water production may result from combined effects of increased vertical permeability, lower density of perforation and high-velocity gas flow around the wells.