To raise the coal seam permeability,ensure maximum CBM desorption and migration,effective well diameter 3~4m and certain extent of fracture zone are generally required in well caving completion.

Based on the principle of grey association analysis,the present paper has put forward a fairly practical and readily programmed cluster method—grey association cluster method,and employed this method to demarcate coal beds and gas beds,discriminate between coal-produced gas bed,oil bed and water bed ,and make lithostratigraphic classification.

Research on hydraulic direction technology for horizontal drilling of coal bed methane;

Developing features of fissure system in Henan coal reserves seams and research on mining of coal bed methane;