Technical analysis on radial horizontal well for development of coalbed methane of low coal rank

Coal seam of low rank has different characteristics, such as low mechanical strength, high permeability and rich endogenic fissures. A new method to improve the production of low rank coalbed methane is put forward, in which radial horizontal well is drilled earlier than hydraulic fracturing. The aim is to expand and communicate more endogenic fissures in coal seam by the radial horizontal well drilled in advance and then enhance gas production. In order to resolve the problem of sand production, screw pump or electric submersible screw pump can be adopted in preference to other pumps. According to the coal seam conditions of Fuxin Liujia block and Hunchun basin, feasibility of joint application of radial horizontal well and hydraulic fracturing is studied. It is proposed to optimize well deployment method, jointly implement under-balanced drilling and jetting with flushing. It can play their different dominant roles and develop to an incorporate coalbed methane development technology. By incorporated improvement of radial horizontal well and hydraulic fracturing, a new method to develop low rank coalbed methane is put forward.