Perforating cemented casing is a staple for completing wells in every major basin in North America. The objective is to provide a highly conductive pathway between the wellbore and the target formation for both the stimulation and production fluids. New technology, statistical analysis, experimentation and trial-and-error are all used to find the optimal method for creating this pathway. Diagnostics like proppant tracers, downhole cameras, distributed temperature sensing (DTS), distributed acoustic sensing (DAS) and perforation friction pressure analysis can also be used to help evaluate the successes associated with the different methods for perforating. New technology in creating consistent hole perforations in a horizontal wellbore, without the need for mechanical centralization or positioning systems, has recently been developed. This method of perforating employs a specialty shaped charge that allows for more control in the distribution of entry hole diameter (EHD) across a given cluster. This provides operators a more predictable and consistent pathway from the wellbore to the formation. Not only is a consistent hole desirable in a standard multi-cluster stage treatment, but other recent completions trends can also benefit from increased precision in perforating. High density perforating (HDP) is being used in order to create more transverse fractures along the length of the well. A consistent hole allows for more precise estimations of pressure drop across each cluster in these mostly limited-entry or extreme limited entry (XLE) completions. Additionally, near-wellbore (NWB) perf sealing pods are being used to divert treatments from initially open clusters to bypassed or partially open clusters in an attempt to force perf cluster efficiencies higher and distribute stimulation fluids and proppant more evenly. Having a consistent hole for every perforation is ideal in attempting to seal the perforations in the NWB region with a fixed diameter pod. SPE 189900 (Senters, et al 2018) provides more detail on diversion optimization. Engineered completions design is employed in an attempt to selectively perforate rock within a stage with similar mechanical properties to drive stimulated cluster efficiencies higher. Perforating similar rock with a consistent hole shaped charge only stands to improve the chances of distributing the treatment more evenly throughout the clusters. This paper will provide insight into the recent trends in perforating which show an increase in the amount of consistent hole shaped charges versus conventional shaped charges like deep penetrating and large hole. Diagnostic data accompanies entry hole diameter statistics and friction pressure calculations for the consistent hole shaped charges in order to demonstrate how they differ from conventional shaped charges. Finally, proppant tracer diagnostics will highlight several case studies where consistent hole shaped charges or other recent perforating methods were employed.

Oilfield water and oil tracers have historically been pumped into the fracturing fluid during well stimulation. This paper will introduce an alternative method of injecting oilfield tracers that utilizes perforating guns with energetic propellant to force the tracer into a perforation cluster prior to fracturing operations. Direct tracer injection from perforating guns offers several advantages to operators that are interested in oilfield tracer diagnostics, they include:Monitoring a wells oil or water returns down to an individual cluster level of resolution.Energetic propellent assisted perforation cluster breakdown.Direct tracer injection into clusters for wells that are: Perforated but not hydraulically fractured.Bullhead refracturing treatments with long open intervals of newly fired perforations.Not sufficiently isolated between stages from poor cementing or leaking plugs.Not isolated or experimentally isolated between stages. Oilfield tracers in solid form were first injected into perforation clusters with energetic propellants on two Marcellus Shale wells. The primary purpose of this experiment was to determine if Perforation Gun Tracing (PGT) could be used to provide flow-assurance diagnostic information to the well operator. Additionally, standard liquid water tracers were also injected into the flowstream during the corresponding fracture treatment stages and used as a control for the PGT. Both tracer injection methods indicated that the toe side of the wellbore was contributing to the fluid returns profile and also showed similar trends in tracer response over time. This experiment showed that PGT could provide valuable diagnostic information to well operators. Several additional field trials that exploit the unique benefits of PGT were completed after the success of the initial experiment and are included in the case studies section of the paper. In each case, PGT was able to provide the intended diagnostic which included flow-assurance, flow-profiling, fracture driven interactions and/or refracturing effectiveness. In refracturing, PGT has tremendous benefits because the energetic propellent can help the new perforations breakdown and compete with the existing broken down and eroded perforations. Additionally, unique tracers are injected at several known cluster depths throughout the lateral. Any returns of the unique tracers in the flowback water will correspond to fracturing fluid that has contacted the depth of that specific traced cluster. This provides an operator valuable diagnostic information to determine how deep their refracture treatment was able to reach into the lateral. PGT also delivers information on the returns of an individual cluster, without post-frac well intervention or permanent hardware installation.