Seepage equation of coal-bed gas in geophysical field

According to the seepage properties of coalbed gas affected by in-situ stress field, geothermal temperature field and geoelectric field, the coal-bed gas permeability κ(σ, T, E) is investigated and obtained in geophysical field. The results indicate that coalbed gas permeability is related to the effect stress σ with a negative index, to the geothermal temperature T with a power function and proportional to the geoelectric field strength E. By establishing coalbed gas flow equation, coalbed gas flow continuity equation, coalbed state equation and coalbed gas content, the coalbed gas seepage equation is gotten in geophysical field. The coalbed gas seepage equation contains common influence of in-situ stress field, geothermal temperature field and geoelectric field on coalbed gas seepage properties. As a new theory, the coalbed gas seepage equation will be as a theoretic basis to discuss coalbed gas flow law in geophysical field under certain conditions.