ABSTRACT
The dual porosity, anisotropic properties of coal beds make them good candidates for horizontal well completions. This paper presents an analysis of transient pressure response of a horizontal well in a coalbed reservoir. In general, the early time pressure response is distorted by the effect of wellbore storage. The general practice in such cases is to evaluate the time to the end of wellbore storage in a horizontal well using infinite conductivity fracture solutions. In this paper, a new, semi-analytical solution is developed to account for wellbore storage and skin effects on the pressure response of a horizontal well. This solution is developed for semi-infinite, anisotropic coalseam reservoir with single phase gas flow. With this solution, type curves can be generated for particular applications, allowing for calculation and verification of reservoir parameters including sorption properties of coals. Examples of the type curves are presented. An example of the analysis is given.
