Study of main factors having impact on fracturing results of coal seams and appropriate countermeasures

摘要

Notwithstanding the abundant low-permeability CBM reserves in China, the targets of efficient exploitation cannot be actualized by any way other than hydraulic fracturing (which could reconstruct the coal seams, subsequently having much more natural fracture system got communicated with each other). Due to the unique features of coal seams (i. e., low temperature. strong adsorption, and abnormal development of natural fracture systems) as compared with the conventional reservoirs, however, the risk of hazards (including those against coal seam itself and the hydraulic fractures) would be extremely high in the course of fracturing; meanwhile, the fractures propagate in a regularity which is extremely hard to understand, further intensifying the difficulty faced by the fracturing deployment. As a result, losses would be suffered on the side of post-frac flow of CBM holes. After firstly probing into the main factors having impact on the post-frac results as well as the extent to which the impact is brought, this paper puts forwards the technical solutions for the improvement of the fracturing performance.