The wettability decides the fluid distribution in porous media

and the wet-phase fluid will primarily occupy the smaller pore. Based on this principle

the paradox between laboratory test of coal wettability and state of fluids distribution is analyzed. On the view of wettability

two possible coalbed methane（CBM） storage types are proposed. When the coal is gas-phase wettability

owing to capillary pressure

the free gas and adsorption gas can be trapped in matrix （smaller pore system） by the water in cleat （larger pore system）. In matrix system

the sorption of gas is in equilibrium state

but the storage of gas is in the undersaturated state. The critical desorption process results from the capability pressure of water and gas. When the coal is water-phase wettability

the matrix is saturated by water

and the coalbed methane can store in the matrix in liquid-phase sorption state. This study designs the experiment to validate the gas liquid-phase sorption. The results indicate that a mass of methane can be adsorbed in the matrix in the liquid-phase sorption mode.