Diverter / Limited Entry

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Figure 1: A reservoir section overview of the overall performance of the wellbore. The production shows to be uniform without any sign of serious degradation at the different completion designs.

It is understood that multi-stage completions can reduce well costs significantly; however, clients are left with wondering if multistage completions come at a cost of reduced production at the surface. This case study will focus on a US unconventional well, where the Z-system® deployed a 0.6” OD, 22,000-foot-long carbon fiber rod to acquire DAS and DTS to evaluate the effectiveness of diverter. The main objective of this run was to use DFO measurement during a post-frac sensing operation to provide a clear and thorough understanding of diverter efficacy.

The main objective for this analysis was to determine which of the two-completion designs used by the operator is more effective. The client is using diverter treatments for multistage completions and wanted to compare them to their single stage completions. Using the Z-System®, DAS and DTS data was acquired to provide a cluster level understanding on the differences between each completion type.

Figure 1 below shows an acoustical representation of the wells overall performance. The well had a uniform production profile throughout the later indicating no serious degradation of production with any one type of completion. The completion diagram on Figure 1 shows single stage completions in pink and multi-stage completions in gold.

Doing a qualitative analysis on acoustical measurements, Table 1 shows the results for both cluster efficiency and stage strength. Cluster efficiency describes what clusters are contributing to the flow and stage strength provides a qualitative assertion on the rate of that flow. Table 1 shows that the multi-stages completed with diverter outperformed the single stage completions. Figure 2 shows a bar chart that has arrows pointing at the single stage completions where the bars illustrate cluster efficiency and red line indicates the stage strength at each stage. It can be noted that most of the stages with the arrows above them were under performing compared to the multi-stage completion approach.

When evaluating stimulation and completion design techniques, using intervention based DFO technology such as the Z-system® will give a thorough diagnostic to ensure maximum recovery at minimum completion cost.

Table 1: Single stage vs. diverter multi-stage completion

Completion TypeCluster Efficiency (%)Stages Strength(NP/ft*100)
Single Stage83.33%7.9
Multi-Stage92.9%10.6
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Figure 2: Bar chart and line graph, showing cluster efficiency and stage strength respectively, to break down the overall performance between single stage and multi-stage completions.