In this work, different measurement methods have been used to investigate the quality of the cement sheath inside two cemented “sandwich” sections, including high-resolution ultrasonic cement-evaluation logs, sample analysis, mechanical loading, and fluid-seepage measurements. The examined sections were recovered from a North Sea well during a permanent plug-and-abandonment operation. The measurements have been analyzed with an aim of describing in detail the spatial variations in the cement properties and relating them to the logs. The data analysis has improved the understanding of the cement-sheath mechanical properties, seal quality, and response of the ultrasonic cement-evaluation logs.
Introduction
A well drilled at the Valhall Field was permanently abandoned in 2018 after being in production since 1985. To install the surface plug, the 9⅝-in.
