Acoustic Imaging of Perforation Erosion in Hydraulically Fractured Wells for Optimizing Cluster Efficiency

Abstract

A new solid-state, high-resolution acoustic imaging technology has been applied in hydraulically fractured wells to image and quantify perforation erosion. The downhole device captures detailed full-lateral logs of horizontal wells, without the need for clear fluids to facilitate measurements. This paper discusses how the imaging technology functions, lab testing that validated the measurements, and field testing completed with several operators in a variety of reservoirs and basins. This high-resolution, acoustic-based downhole imaging technology provided a 360-degree view inside a variety of wells. Instead of optics, the imaging technology used high-frequency sound waves to image a full lateral through opaque fluids at sub-millimetric levels. The imaging tool was conveyed on either tractor or e-coil to continuously log the wellbore between 15 and 30ft/min, completing a full azimuthal scan that imaged individual perforations regardless of orientation. A range of imaging techniques quantified and measured each perforation to determine the extent of erosion in each perforation, cluster, and stage sustained during the hydraulic fracturing process. The acoustic imaging technology was initially tested in the lab with calibration jigs and perforated pipe samples to validate its accuracy. The technology was then field deployed by several operators and used to assess perforation erosion in extended horizontal wells by scanning the entire well from toe to heel and measuring thousands of perforations in a single log. The data gathered quantified the perforation diameter, perforation erosion range, perforation orientation dependency, cluster efficiency, perforation erosion bias, and discovered the presence of significant casing damage around areas where plugs were set. The image results showed the distribution, size, and measured diameter for each perforation in each cluster. The results noted toe or heel biases and how these changed in different well types and designs in different basins. The data allowed operators to reach conclusions regarding erosion and cluster efficiency across the entire lateral in various wells in the Montney, Permian, and Anadarko basins. Wells across North America were scanned in several other basins for comparison purposes using various completion designs from different operators. The high-resolution acoustic imaging technology offers a robust 360-degree view of long horizontal wells and perforation measurements post-fracture. Over 35,000 perforations have been measured using the technology in the field across various well types with different designs. The technology has proven to be a valuable tool in improving and optimizing completion designs by providing detailed feedback on where designs are working effectively and where they can be improved.

A Model for Optimizing Proppant Distribution Between Perforations

“…A more detailed version with examples can be found in [29]. The workflow for optimizing perforation design employs StageOpt simulator and observation of field-scale phenomena, such as downhole imaging that provides costeffective and high-fidelity assessment of the magnitude and location of perforation erosion within a stage [26,30]. The data can include the equivalent diameter, as well as axial and circumferential diameters.…”

One Stage Forward or Two Stages Back, What are We Treating? Identification of Internal Casing Erosion During Hydraulic Fracturing - A Montney Case Study Using Ultrasonic and Fiber-Optic Diagnostics

“…A Midland basin case was reported by Murphree et al (2020) where unexpected casing breaches were observed at 16% of the frac plug set depths. An abundance of downhole acoustic images was provided to demonstrate the correlation between casing erosion and frac plug location (Robinson et al 2020).…”

Research on the erosion law of shale gas casing perforation hole during fracturing

“…So as to improve the effectiveness of fracturing operation. S robinson [8] used the acoustic system to evaluate the hole erosion in the perforated section of a horizontal well. After quantifying the collected data, the hole diameter, hole erosion range, hole erosion offset and other information are obtained.…”