Abstract: NMR lines of fluids on the rock core surface are found.Analysis indicated that they originate from the diffcrence in susceptibilities between rock matrix and free fluid.When some of the fluids leaked out from the rock pores,the fluids exit in two states,i.e.inside the rock and outside the rock,their susceptibilities are different,The intensity of the new resonance lines increases with time and tends to a constant value,this procedure is rclated to the permeability of the sampie.So it is possible to develop a method to deteimine rock pemeability from the surface fluid lines.

Key words: Rock sample, NMR spectrum, Permeabilty