Abstract:

The coalbed gas is an important resources, the activities of the research and the development are very active. The main characteristics of coalbed reservoir are low permeability and low porosity, the effect that the normal method developed coalbed reservoir is not good. The technology of fracture and horizontal well is an effective method improved output of coalbed gas.
Fractured horizontal well is a potential way developed coalbed gas, applying potential function principles, superposition principal and mathematical method for solving matrix. In the process of formula derivation, many factors, such as, anisotropy of reservoir matrix, numbers of fractures, fractured on horizontal
well's productivity and fully or partially penetrating in the formation and so on, were considered. Finally, in the paper the calculation example was given, and a few factors have been compared and analyzed. The results show that the relation between the horizontal well's productivity and the number of frac-
ture is direct ratio, the suitable number of fracture is no more than 10 in the horizontal length of the well, besides, the rate of penetrating of fracture should under 0.15, if the rate of penetrating of fracture overweight 0.15, it is not sensitive that the output are affect the rate of penetrating of fracture.

Key words: Coalbed Gas, Fracture, Horizontal Well of Productivity