シミュレーションによる地山ガス抜きに関する考察 (第1報)
1982 年 98 巻 1131 号 p. 399-403
詳細
1982 年 98 巻 1131 号 p. 399-403
The state around borehole in a coal seam is considered as shown in Fig. 1. This state can be expressed by the simple model as shown in Fig. 2. In this model the gas flow from coal seam to the borehole is considered as consisting of the Kiyoshi HIGUCHI1, Toshiro ISOBE2 and Kotaro OHGA3two-courses; one is direct radial flow toward the borehole, the other is linear flow toward the discoidal fracture.
The total gas flow from the borehole including these two-flows is expressed by the equation (2).
This partial differential equation is solved numerically by using a digital computer.
From the comparison of the calculated results with the observed values following results are obtairled.
Permeability of the coal seam in YUBARI district is smaller than that of the KITASORACHI district, but r1 value (the apparent radius of the discoidal fracture) of the coal seam in YUBARI district is larger than that of the KITASORACHI district.
The larger the r1 value, the more easily methane in the coal seam can be drained.
