Abstract: Non-resistivity flow in a gas well may be decreasing constantly with the formation pressure lowering.Therefore，a gas well has its different non- resistivity flows in different producing stages. In order to avoid multiple and repeat productivity well testing to a gas well in different producing stages, this paper presented the formula for calculating binomial cofficient in different formation pressures, based on the binomial productivity-calculated equation for gas wells, by which more reasonable non-resistivity flows of gas wells in different producing stages can be simply obtained. Field case application showed that the method is simple and practical to use.

Key words: formation pressure, well test, binomial, open flow capacity, deviation, coefficient, viscosity