Characteristics and technical measures of exploration and development of coalbed methane reservoir in Guizhou Province: A case of Bide-Santang area

The rational transformation of reservoir and reasonable drainage technology are the key links for CBM exploration and development. On the analysis of CBM geological and reservoir characteristics in Bide-Santang area, the CBM geological characteristics are summarized as multiple seams, big cumulative coal thickness (more than 20m), and high gas content (more than 15 m³/t), high resource abundance (more than 2×108 m³/km²), high ratio of critical desorption pressure and reservoir pressure (more than 0.8). But there exist many faults, big distance among coalseams (about 300 m), high ground stress, low permeability, poorly water-bearing. The technologies were proposed such as sataged fracturing by fishable bridge plug, staged fracturing by hydraulic jet with coiled tubing, staged fracturing by combined operation of cable perforation and bridge plug, fracturing fluid compound of little damage. Progressive drainage technology was adopted. Pipe string was optimized. Refined drainge with dynamic analysis was carried out.