SPE-PB Chairman 2020-2021
Senior Reservoir Engineer
Endeavor Energy Resources
This month’s section meeting will be a distinguished lecture covering “Making Decisions Using Completions Diagnostic Tools in Unconventional Reservoirs.” I thought it would be a good idea to discuss completion diagnostics case studies in Permian Basin unconventionals.
I wanted to start with a 2016 paper and progress to more recent studies to show how our understanding has evolved in the Basin. SPE-181679 discusses various completions diagnostics in the Wolfcamp formation for both Midland and Delaware Basins. The paper details how proppant and fluid tracers were used to come up with changes to well completion design. For instance, fluid tracers and proppant tracers helped identify fractures and/or faults. Completion cost per well was lowered by bypassing zones that were unproductive. The paper also found that uniform flowback trends of fluid tracers across a single lateral are indicative of uniform proppant placement. Additionally, uniform proppant placement across the lateral was a result of hydraulic fracturing of similar types of rock. This was accomplished by either controlling the drilling to stay within the targeted interval or by selectively adjusting the stage lengths to stimulate similar rock types together (Warren et al 2016).
Fast forward to 2018, where URTEC 2902960 covers the interwell communication between Upper Wolfcamp and Middle Wolfcamp wells from the Midland Basin Hydraulic Fracturing Test Site (HFTS). The paper examined the water, oil and proppant communication between wells at different targets. Unique tracers were employed in conjunction with many additional diagnostic technologies to evaluate interwell communication, fracture behavior, proppant transport and reservoir drainage.Figure 1 (Figure 4 from the paper) below shows the gun barrel view of these wells:
Figure 1: Gun-barrel view of Upper and Middle Wolfcamp wells, where wells labeled in white are not traced.
The study had many conclusions from the completions diagnostics. For instance, proppant tracer results indicated a high degree of cluster efficiency can be obtained through the three cluster 90’ spacing design, however, it left behind a larger percentage of unstimulated rock. Stimulated rock coverage increased through a higher density, five-cluster, 50’ spacing perf scheme without sacrificing perf cluster efficiency. Additionally, proppant tracers showed similar near-wellbore proppant placement when applying the same completion strategy to both the Upper and Middle Wolfcamp benches. Interwell communication within MWC wells was significantly higher than communication within UWC wells. Vertical communication was greater from MWC wells to the UWC wells. Finally, the frac fluid communication observed, while stronger in magnitude early, continued through two years of flowback sampling. Therefore, a need exists to further optimize completion designs and/or well spacing by not only formation, but also by each bench within the formation (Wood et al 2018).
The last paper I wanted to cover was a 2020 paper: SPE-199712, “Evaluating Limited Entry Perforating & Diverter Completion Techniques with Ultrasonic Perforation Imaging & Fiber Optic DTS Warmbacks” from SM Energy. This is another angle in completions diagnostics that this paper covers compared to the previous papers mentioned. The team evaluated extreme, limited-entry perforating and particulate diverter completion techniques with ultrasonic perforation imaging and distributed temperature sensing (DTS). The study discusses Midland Basin, horizontal wells completed with varied completion designs. From this work, stage spacing was increased by 25% with no indication of performance degradation utilizing diverting agents and limited-entry perforating. Near-wellbore diverting agents do not stimulating new clusters, as erosion data shows that all clusters are receiving frac slurry with or without diverter, but it also shows that diverter is effectively redistributing proppant and fluid. Warmback data and perforation erosion data show no correlation indicating that perforation erosion does not always result in fracture creation. Wellbore trajectory and inclination appear to be a factor in proppant placement. Additional future work the study proposes are pushing the limit of stage lengths to find the point of diminishing returns with limited-entry perforating and diverting agents, continuing to evaluate the role of well trajectory on proppant placement, optimizng the amount and timing of diverter drops, and incorporating an in-depth cement evaluation with these completion diagnostic tools (Murphree et al 2020).
From the past few years, our understanding of the Basin has increased to improve completions and development designs. With a combination of proppant loading, cluster spacing, and how perforations are placed, we are able to optimize what the Permian Basin has to offer. We look forward to everyone’s participation in this month’s SPE events, especially for the section meeting.
- Murphree, Chase , Kintzing, Malcolm , Robinson, Stephen , and Jay Sepehri. "Evaluating Limited Entry Perforating & Diverter Completion Techniques with Ultrasonic Perforation Imaging & Fiber Optic DTS Warmbacks." Paper presented at the SPE Hydraulic Fracturing Technology Conference and Exhibition, The Woodlands, Texas, USA, February 2020. doi: https://doi.org/10.2118/199712-MS
- Warren, Mark N., Dempsey, Christopher J., and Robert A. Woodroof. "Wolfcamp Completions: Lessons Learned through the Implementation of Completion Diagnostics to Optimize Existing Drilling and Stimulation Practices." Paper presented at the SPE Annual Technical Conference and Exhibition, Dubai, UAE, September 2016. doi: https://doi.org/10.2118/181679-MS
- Wood, Tanner, Leonard, Richard, Senters, Chad, Squires, Chris, and Matthew Perry. "Interwell Communication Study of UWC and MWC Wells in the HFTS." Paper presented at the SPE/AAPG/SEG Unconventional Resources Technology Conference, Houston, Texas, USA, July 2018. doi: https://doi.org/10.15530/URTEC-2018-2902960