Over the last decade, an industry wide shift to unconventional plays has occurred due to advances in technologyallowing for the recovery of previously uneconomic reserves. The primary objective of completions in theseunconventional reservoirs is to increase the effective surface area of the well to maximize reservoir contact.Horizontal drilling and multi-stage fracturing are two technologies which have accomplished this.The two main methods of horizontal, multi-stage completions currently used in unconventional reservoirs arecemented liner "plug and perf" and open hole, multi-stage fracturing systems. This paper provides an introductionto unconventional reservoirs, describes the main methods of horizontal, multi-stage completions, and discusseshow the choice of method can affect good fracturing practices as well as long-term production. Case studyexamples are presented from a variety of unconventional reservoirs including shale, tight sandstone and tightcarbonate formations.Operators working in a number of unconventional reservoirs, such as shales and other tight rock formations areexperiencing faster than expected production decline rates, resulting in reduced long-term, ultimate recovery. Thismay be in part due to the abandonment of good fracturing practices with the advent of horizontal, multi-stagefracturing. Issues such as near wellbore conductivity, flowback, and fracture tortuosity, which can have asignificant effect on the long-term production of wells, need to be considered when choosing a completionmethod, particularly for unconventional reservoirs.Unconventional plays are becoming a significant part of the oil industry today and will become a bigger part in thefuture. It is important that the reservoirs are completed optimally to achieve maximum recovery. The informationprovided in this paper is applicable to unconventional resource plays worldwide.
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