Laboratory Testing and Productivity Numerical Simulation for Fracturing CBM Radial Horizontal Wells

Fracturing to CBM (coalbed methane) radial wells is expected to be an effective means in China for hydraulic fracturing stimulation after one or multiple radial wells are drilled in the target coal seams. In order to understand the fracturing effect ont he coal seam, a physical simulation was carried out on the fracturing process of radial wells by using large-scale true tri-axial hydraulic fracturing test equipments, and consequently three fracture morphologies were obtained. The influential rules of borehole parameters on the fracture initiation and propagation were analyzed on the basis of the experiment results. In addition, a model for coal seams stimulated by the radial horizontal well fracturing was constructed by using numerical reservoir simulation software. The great potential of radial horizontal well fracturing in high-efficiency CBM exploitation was demonstrated by comparing the productivity in different well completion modes. It was proposed that a radial well fracturing network should be formed as one horizontal fracture and multiple vertical fractures. Finally, the specific engineering design suggestion was put forward, and provided a theoretical basis for the application of radial fracturing to the development of coalbed methane.