Forked Wellbore Completions Improve Development Strategy

Abstract

In recent years nearly half of the development wells drilled in the Southeast Geysers were, at best, capable of only marginal steam production from their original producing interval. Traditionally, this original hole "leg" was plugged and abandoned and the well directionally redrilled, usually from the casing shoe, to an alternative bottom hole target. Often two or even three such redrills were required before an economically acceptable producer was realized. Northern California Power Agency (NCPA) has recently developed an innovated drilling technique whereby a subcommerical original hole producing interval is retained and its production is then combined with that obtained form the redrilled leg, resulting in a "forked" completion. Six such two legged well completions have been attempted in the past two years, all o f which were successful. This technique has permitted the profitably exploitation of heretofore economically unattractive or marginal areas of the reservoir.