Evaluating and Optimizing Completion Designs in the Niobrara Formation of Powder River Basin Using Multiple Diagnostic Datasets
Authors: Jones Matt , Zhao Yu , Borski Jack , Puyear Jess , Nilemo Jon , Fernandez Juan , Tan Kenneth , Kethireddy Nikhil 
Published: January 2025

Objectives/Scope

Many factors in unconventional stage design can significantly impact well performance. This Powder River Basin project deployed a rigorous completions Design of Experiment (DoE) on a Niobrara horizontal well to evaluate Stimulation Distribution Effectiveness (SDE) for different stage configurations while attempting to increase stage length and maintain a high degree of treatment uniformity. The primary tools used to evaluate performance were permanent fiber, offset disposable fiber, high-resolution acoustic imaging, and pre- and post-frac water saturation logging.

Methods, Procedures, Process

Hydraulic fracture profiles (HFPs) were generated at the cluster level for every stage using Distributed Acoustic Sensing (DAS) data collected in real-time by the permanent fiber during stimulation. These HFPs were used to calculate SDE parameters, such as Proppant Distribution Metric (PDM) and Proppant Uniformity Index (PUI), to assess the different stage configurations and determine what combination of variables yielded the best performance. Similar SDE parameters were calculated using perforation (perf) entry and exit hole measurements obtained from post-frac acoustic imaging. These datasets were also compared to the information obtained from offset disposable fiber as well as pre- and post-frac water saturation logging.

Results, Observations, Conclusions

This work demonstrates the successful execution of a robust completions DoE and the ensuing analyses of diverse diagnostic datasets. While permanent fiber was used as the primary means for assessing treatment uniformity, its results had a high degree of alignment with the results from other tools used in the project. Based on the analytical results, Rate per Cluster (RPC) and perf orientation were determined to be two variables that directly impact SDE. Stage configurations that generated higher levels of RPC tended to yield better values of PDM and PUI than those that generated lower levels. Additionally, for the same stage configuration, stages that were perforated in the upper section of the borehole tended to outperform those that were perforated in the lower section. Of particular interest was the performance difference between stage configurations using multi-perf clusters and those using single-perf clusters with large-diameter perfs. With all other design variables kept consistent, stage configurations with single-perf clusters showed a noticeable uplift in treatment uniformity compared to their multi-perf cluster counterparts. There also appeared to be no meaningful correlation between Rate per Perf (RPP), which is a proxy value for perf friction pressure, and SDE.

Novel/Additive Information

This project reinforces RPC as a primary driver for SDE while also highlighting the importance of perf orientation. Instances where single-shot clusters with large-diameter perfs have been tested in a well equipped with permanent fiber are also rare. Although the dataset is small and additional testing is needed, it is encouraging to see that better treatment uniformity can be achieved using a fundamentally different perforating strategy while keeping other design parameters consistent.