ABSTRACT
The gas flow in coalbed is mainly dependent on coalbed gas permeability (k), and coalbed gas permeability (k) will be affected by geostress field, geothermal field and geo-electric field. In this way, coalbed gas permeability k(σ, T, E) is investigated and obtained in three fields. The results indicate that coalbed gas permeability is a negative index to the effect stress (σ), a power function to the geothermal temperature (T) and a proportional to the geo-electric field strength (E). By establishing coalbed gas flow equation, coalbed gas flow continuity equation, coalbed gas state equation and coalbed gas content equation, coalbed gas seepage equation is gotten in three fields. The coalbed gas seepage equation contains common influence of in-situ stress field, geothermal field and geo-electric field on cabled 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 three fields under certain conditions.
