Abstract: CBM combined drainage by up and down well is an important form in coal mine area in China. Firstly, this paper introduces the scientific connotation and realization mode of CBM combined drainage by up and down well, and analyzes the current situation and existing problems, including the combination of coal bed methane development method and construction technology, and the construction technology is divided into with the strip borehole and well drilling, long borehole drilling with underground well, combined fracturing, three-dimensional fracturing, roof fracturing and well with borehole docking. In view of the demand and problem of CBM combined drainage by up and down well, the combined drainage of CBM from the vertical well and the horizontal borehole underground is put forward, and the combination of drainage channel and drainage process is realized. Finally, the prospects for the development of CBM combined drainage by up and down well are presented.

Key words: coal mine area, CBM development, up and down well, CBM combined drainage, research progress