Cement-job evaluation is a process that identifies whether the objectives of a cement-job operation have been achieved after cement placement. This paper reviews the technology trends in cement-job evaluation using logging tools and considers the main advantages and concerns associated with each technology. The technologies covered are acoustic tools, temperature logging, noise logging, resistivity logs, oxygen-activation logs, X-ray measurements, gamma/gamma density measurements, neutron/neutron logging, and fiber-optic measurements.
Introduction
After a cementing operation has been performed and the cement has set, cement evaluation is conducted either through hydraulic testing or by using various well-logging methods. Verification of casing-cement quality by logging tools has been a contentious subject for the past few decades.