Completion optimization continues to be a priority for many operators. The process of adding diverter to hydraulic fracturing treatments remains one of the fastest growing techniques to gain operational efficiency while maintaining the desired reservoir contact during the treatment. Case studies in this paper are utilized to illustrate the effects of diversion on the overall completion program. Evaluating diversion effectiveness and relating it back to overall completion effectiveness remains a challenge with surface pressure data alone. Diagnostics in the form of proppant tracing are applied to evaluate the near-wellbore coverage of the stage with the use of diversion. These stages are also evaluated based on the shift in treatment as a result of the diversion. Unique proppant tracers are utilized before and after diverter drops to evaluate changes in the treatment over time. The results of diversion based on the overall stage coverage and the role that the diverter played in obtaining this coverage is presented in several case studies. Examples include data from projects that utilize different types of diverting techniques. The overall completion effectiveness based on missed clusters is illustrated in the case studies presented in this paper. Diversion cleanup and fracture interference while using diversion is evaluated using chemical tracers. Diversion will be discussed in an interwell communication case history. In addition to the evaluation of diversion, baseline examples are included without diverter material. These baseline examples are sometimes referred to as "ghost stages." The diagnostic approach to this compilation of case histories compares the results of over 20 wells using completion diagnostics. All of the stages evaluated are summarized for perforation efficiency and diversion effectiveness.

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Success of a fracture stimulation treatment depends upon complete coverage of all targeted intervals. Diversion techniques are being applied in new well completions to achieve greater cluster treatment efficiency and to access additional rock. The objective of this study is to characterize diversion and to utilize near-wellbore diagnostics to determine the effectiveness of diversion. Multiple basins are included in this study, incorporating a variety of drilling and completion practices. Proppant tracing and temperature logging provide near-wellbore diagnostics to evaluate the new rock contacted as a result of diversion. Tracers injected during the treatment at various intervals before and after diversion can be used to determine cluster efficiency as well as the overall changes to a stage as a result of the diversion. Temperature logging is used to determine cooling effects of the treatment and is correlated back to the near-wellbore proppant coverage. The combination of multiple diagnostics provides additional confirmation of the treatment coverage or in some cases the lack thereof. The results of this study show examples of both effective and ineffective diversion. Effective near-wellbore diversion is defined as diversion that results in accessing clusters that were previously not stimulated or under-stimulated. In many cases the surface treating pressure response due to diversion does not correlate to its effectiveness. Optimizing the design and deployment of the diversion process often results in improvement of treatment effectiveness. The results of this study are grouped by Anadarko Basin, Permian Basin, Eagle Ford, and Williston Basin and show the effectiveness of a variety of diversion techniques. Through a combination of diagnostic techniques, diversion is evaluated on new well completions. Over 30 wells are included in this study across multiple basins. The overall stage coverage is evaluated along with the effectiveness of near-wellbore diversion to achieve this coverage. These learnings can be applied to optimize diversion designs for future wells in these and other basins.

Refracturing continues to provide operators with the opportunity to add production at a fraction of the cost to drill and complete a new well. Various re-stimulation designs and diversion techniques are currently being utilized to maximize contact with previously un-stimulated rock. Optimizing this process involves evaluating all available diagnostic, pressure and production data and determining the optimum design that maximizes recovery. This paper describes how these diagnostic technologies have been employed to evaluate and optimize refracs in four major North American basins. The process of refracturing and recompleting wells continues to improve. Much of this improvement comes from the optimization of techniques through completion diagnostics. Diagnostics provide data that can quantify the amount of the lateral treated and the effectiveness of diversion. Operators are focused on bridging the gap between the completion methods commonly used at the time the well was originally completed and the methods of today. Application of completion diagnostics also assists in identifying opportunities to further reduce the cost of the project while achieving similar results. In this study, proppant tracing followed by spectral gamma ray logging was employed to evaluate the effectiveness of the refracs, the extent of new rock contacted, the benefits of reperforating, and various diversion methodologies. Diagnostic results from 121 vertical (34) and horizontal (87) refracs covering 16 different formations and 26 different operators were analyzed and compared based on stimulation effectiveness and performance. The wells were then grouped by well type, formation and the basic refracturing technique that was utilized. In addition to the macroscopic data interpretation; four case histories are presented from the Barnett Shale, Permian Basin, Eagle Ford, and Haynesville. These case histories include before and after reservoir production matching with fracture half-length and effective conductivity calculations along with the diagnostic analysis of new and existing perforation coverage, diversion effectiveness, and ultimately the % incremental estimated ultimate recovery (EUR).

Horizontal drilling and hydraulic fracturing techniques continue to drive the profitable development of previously uneconomical reservoirs. In many basins across the world, economic exploration and production activities are a prerequisite for developing these unconventional reservoir projects, as well as vertically-drilled conventional reservoir projects. The specific examples in this paper are located in the Anadarko Basin and Appalachian Basin. Completion diagnostics are being employed to validate the drilling and completion optimization of wells across all of the major unconventional plays in North America. This paper focuses on three specific projects in which the diagnostics implemented in horizontal completion programs led to significant cost reductions and efficiency gains. All of the wells in the discussed projects utilized at least one type of completion diagnostics to implement cost savings or optimize drilling and completion practices. Eliminating unnecessary wellbore interventions reduces costs and lowers operational risks. In order to justify the need for a wellbore intervention, completion diagnostics are applied during the stimulation treatment. The first case history in this paper reviews data that support the decision to reduce costs by not milling out completion hardware, as well as supporting the expenditure for a wellbore intervention when data indicate flow obstructions along the lateral. The second case history illustrates the evaluation of completion methods ranging from different openhole systems to a cemented plug and perf completion that had a failed cement job. The post treatment diagnostic data are illustrated with actions taken to further optimize the drilling and completion practices in the future. The third and final case history is an interwell communication study that uses fluid tracers to evaluate potential areas of acreage that could be left unaccessed. Interwell communication is evaluated for toe-to-toe communication to determine if the area between toes in adjacent pad completions is sufficiently accessed.