Frac Plug Forensics: Post-Fracture Plug Failure Root Cause Analysis and the Subsequent Impact on Stimulation Performance

Abstract

High-resolution acoustic imaging technology has been developed and deployed to assess the sealing performance of over 11,822 isolation plugs following perforation and fracturing operations. With this information, advanced stimulation performance analysis can be conducted to enable the optimization of future completion designs and well operations. This paper provides insight into how this technology works and showcases its visualization capabilities. Additionally, through case studies, this paper shares how major North American operators deploy acoustic imaging to assess and improve their stimulation performance analysis and completion design. These studies reveal foundational and actionable information regarding the performance of different plug designs run in active frac basins. Furthermore, the downstream impacts resulting from these findings such as stage uniformity and overall perforation growth were also analyzed and presented. By integrating high-resolution acoustics with proprietary imaging and machine vision techniques, this technology provides operators with a 360-degree view of the entire lateral in hydraulically fractured wells. In a single run, sub-millimetric 3D point clouds of data are collected for precise measurements and high-resolution image generation to identify post-stimulation liner damage and breaches at plug locations. In addition to damage and breach identification, phase angle, wall loss, ovality, erosional pattern, and plug slip displacement distances are also precisely determined for a complete assessment of plug performance and zonal isolation. Following a detailed analysis of this aggregate dataset, an insightful plug performance assessment was undertaken by analyzing the 3D point clouds of data at each plug location. Analysis of the high-fidelity renderings and precise measurements revealed a notable performance difference between four commonly deployed plug types used. Select plug types more frequently failed leading to a fully breached casing, while others experienced significant sealing element and casing erosion. Depending on the failure type, uphole, target, and downhole stages may be under or over-stimulated. These effects are quantified in aggregate when analyzing the wells Uniformity Index and perforation area growth. This high-resolution acoustic imaging technology has been used to directly identify and assess plug location damage and breaches faster and more efficiently than legacy technologies. Using the aggregate data collected and through the integration of machine vision algorithms and advanced imaging software, a detailed stimulation performance assessment can be completed. With this dataset, completion design improvements can be made with confidence to decrease stimulation operation risks and increase frac efficiency.