关键词: 气藏, 分支水平井, 产能, 取代比, 计算方法

Abstract: Based on the mathematical method (conform transformation,imaging,superposition principle,and equivalent flow resistance) and the solving method of pesudo three dimension for horizontal wells,this paper presents a new formula for calcula ting the productivity of multiwellbore horizontal wells in a gas reservoir and the skin factors of horizontal well has been considered.By using the well replacement ratio,a method for evaluating the productivity of multiwellbore horizontal wells in a gas reservoir has been derived from the productivity of vertical wells.And the calculating method reported in this paper may also be used to account for gas reservoir anisotropy and well eccentricity should be useful in the initial evaluation of a multiwellbore horizontal well drilling proposal.As an example,the productivity of multiwellbore horizontal wells in an offshore gas reservoir has been tested by using this method,and satisfactory results have been obtained.The comparision between this method and the others introduced in reference indicates that the formula derived here has high accuracy.

Key words: gas reservoir, multiwellbore horizontal well, productivity, well replacement ratio, calculation method