Refracs- Diagnostics Provide a Second Chance to Get it Right
Richard Leonard, Robert Woodroof, Chad Senters, Nick Moore
Presented at SPE Annual Technical Conference and Exhibition, 2015
The surge in unconventional completions over the last 10 years has created a substantial accumulation of previously hydraulically fractured wells that are candidates for hydraulic refracturing (refracs). As new plays are developed over time, refracs offer the opportunity to apply improved stimulation techniques to optimize well performance.
Maximizing new fracture network development is a key to successful re-stimulation of existing unconventional wells. Completion diagnostics are a valuable tool in determining the most cost-effective stimulation and completion parameters, part of the refrac optimization process. All of the major unconventional basins have seen significant design changes over time. Refracs allow the operator to capitalize on this continuous improvement in stimulation design. They also provide an excellent opportunity to add incremental production.
The dataset contains over 65 wells that were re-stimulated during the last 10 years. Stimulation and production information will be provided along with suggested refrac techniques. Several diagnostic case histories for Barnett Shale and Marcellus Shale wells will illustrate various successful approaches to the re-stimulation process. The data will be used to address observed diagnostic metrics.
Key parameters and diagnostic metrics will be defined and utilized for the candidate selection process, refracturing design, and post-refrac evaluation. This is the first macroscopic study of its kind where diagnostic and completion metrics are compared with performance metrics. The focus of this study is to compare the various captured metrics with the incremental estimated ultimate recovery (EUR) percentage gains from the refracs. Additionally, post-refrac production rates will be compared with the existing maximum monthly production. The results of this study should continue to be an excellent tool for further optimization in re-stimulation across North America.