抄録
Coal reserve of Japan is about 20 billion tons. A half of them is in Kyushu and the other is in Hokkaido. The most gassy coal field in Japan is Ishikari coal field in Hokkaido. In Ishikari coal field there were so many underground coal mines, but now all of them were closed. The gas content of coal in the Ishikari coal field is more than 12 m3/t and CBM resources in Ishikari coal field is estimated about 40 billion m3.
There are some reasons why CBM has never been developed in the coal field. One is that the Ishikari coal field is mountain area and most of it is covered with National Forest. Therefore, it is difficult to find the drilling site from the surface and to develop CBM on a large scale. The other one is that it is difficult to drill wells in a soft coal seam such as Yuubari coal and to maintain the wells. Therefore, we are planning to develop CBM to use for local energy in this area.
