Evaluating Plug Failure

Slip marks and wall loss at plug location

Technology Used

HADES-R + HADES-T

Region: Montney
Perforations measured: 1198

Objectives

• Evaluate well integrity and wall loss
• Compare stage designs
• Evaluate under & over-stimulated stages
• Understand plug performance issues
• Get data to optimize completion designs
• Measure proppant distribution

Application

An operator sought to assess the quality of completion of a recently hydraulically stimulated well by evaluating the proppant distribution along the reservoir. Proppant distribution can vary greatly between stages and is often due to stages not being isolated as expected. Plugs not isolating can result in stages being overstimulated while others are under stimulated. These stimulation issues are often undetected at the surface during completions.

Perforations Evaluated

The entire well was inspected in a single continuous high-speed pass and all 1198 perforations were evaluated. A comprehensive perforation erosion report informed the operator where the proppant was distributed across the well – on a per stage, per cluster, and per perforation evaluation granularity. Results showed there was a large variation in the stimulation performance between stages of the same design and a detailed look at each plug location was further carried out to understand why.

Results From Advanced Plug Analysis

A multi-view report with acoustic intensity, radial distance, normalized radial distance, and radial wall loss views provided a detailed understanding of each plug location. Multiple stages showed plug slip marks and casing damage at the plug location, indicating a lack of isolation. Stages directly below the plug damage had more proppant entering the stage. Additionally, a plug was identified to have been placed too far downhole, resulting in a stage being stimulated twice.

Plug Slippage

The acoustic intensity view clearly revealed textual surface changes like slip marks from plugs.

Direct 3D Measurements

An overview of the spacially registered 3D measurements is seen in the radial distance view. Ovality and impressions left by the plug are observed.

Casing Damage

The normalized radial view highlights the subtle marks in the radial distance view. Casing damage from this section’s plug is easily seen in this view.

Wall Loss

The radial wall loss view revealed the exact location of the thinnest areas. A max of 73% total wall loss was measured at this plug location.

Conclusion

This detailed plug analysis informed a Root-Cause Analysis (RCA) and resulted in improved plug setting procedures. This led the operator to significantly reduce plug-related issues, optimize subsequent fracturing operations, and prevent over-stimulating stages – avoiding extensive clean-out runs, and costly Fracture Driven Interaction (FDI) impacting neighboring wells. These insights and operational improvements are advantages operators are gaining from DarkVision’s industry-leading high-resolution acoustic inspections.