2 – CBL in thick walled casing

Thick Wall Casing Cement Evaluation

New generation of Cement Evaluation for thick walled casings

Thick walled cement bond evaluation presented in field as it looks downhole

The uptake in the use of thicker walled casing in recent years owing to casing deformation because of mobile formations and deep-water drilling is increasing. The use of casing thicker than 25mm (1”) has resulted in a limited number of reliable options to verify zonal isolation and well integrity. According to best practices the advised way to perform this evaluation is through sonic-ultrasonic logs, which have independent 360° measurements to identify cement quality, channelling, and micro-annuli.

The yard trial was built with a section of 10 3/4” 109# (wall thickness 1.033”) cemented inside a 16” 84# casing, with various artifacts and cement qualities.

Measurements of internal radius and wall thickness were measured on numerous repeated logging runs, delivering high repeatability and resolution. The plots below provide good measurements over the bulk of the casing section, but operational issues resulted in poor tool centralisation at the top of the run.

Download the full case study here.