Detecting Dents in Pipelines
Wednesday, August 15, 2018

Detecting Dents in Pipelines

Denting of pipelines is a significant challenge faced by those in the Oil & Gas industry, due to the thin-walled steel commonly used to make the pipe. Handling and construction can often result in dents that leave the pipe vulnerable to costly repairs or pipeline failure if left undetected for a long period of time. While there are codes like API-1104 and CSA Z662 that cover the allowable dent dimensions, dents are considered to be a (potentially) serious defect because of the following:

  • Dents interrupt the smoothness of the pipe’s internal bore and can cause “eddies” in the product flow, which may lead to erosion downstream of the dent.
  • Dents are a local stress-strain concentrator. Over time they can lead to cracks in the steel wall which may grow with pressure fluctuation and hoop stress, potentially resulting in pipeline failures.
  • Dents can prevent the passage of In-line inspection (ILI) tools, limiting the ability to safely evaluate your pipeline. Dents result in large signatures on ILI tool logs that can hide smaller signals from cracks.
  • Dents can damage internal linings, especially brittle liners, such as cement mortar or epoxy.

An article about dents and their effect on pipelines can be found here.

Russell's ILI Tools are non-contact, and therefore can pass by minor dents without getting stuck. The RFT technology contained on board Russell's SeeSnake ILI Tools can differentiate between dents and corrosion defects and cracks. Once a dent has been found and the pipe excavated, Ultrasonic evaluation technology is a safe, reliable measure to evaluate the dent and confirm the presence of cracks. Russell NDE provides a vast array of industry leading technologies to facilitate pipeline inspection, especially on pipes with internal liners. For more information on inspecting your pipeline for dents, corrosion, and other age-related degradation, contact our team today.