Abstract: In order to select suitable three-phase foam for sealing fracture around borehole,3 kinds of foam agents,4 kinds of stabilizing agents and 3 kinds of solid-phase filler with different particle diameter were studied.Three-phase foam sealing liquid proportion with high foamability,good stability and strong ability of carrying solid was obtained.The proportion is: 0.4 percent of foam agent FP-1,1 percent of stabilizing agent WP-3 and 4 percent of mixed solid-phase filler with 0.2 to 1 mm diameter.Practical application shows that this proportional three-phase foam has characteristics of little sealing borehole time,rapid determination process and high determination accuracy,which is meaningful for raising the level of gas determination.

Key words: Gas pressure determination borehole, Three-phase foam, Foam property, Material proportion