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 producing from their original production interval. Traditionally, this original hole "leg" was plugged and abandoned and the well directionally redrilled, usually from the casing shoe, to an alternate 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 innovative drilling technique whereby a subcommercial original hole producing interval is retained and its production is then combined with that obtained from the redrilled leg, resulting in a "forked" completion. Five such two-legged well completions have been attempted in the past year, all of which were successful. This technique has permitted the profitable exploitation of heretofore economically unattractive or marginal areas of the reservoir.