Integrated Cement Evaluation Saves Time and Money

Abstract

ABSTRACT Cement bond logs (CBL's) are typically used to approve or condemn cement jobs. This "report card" has caused disputes between the cementing and logging companies for years because typically the CBL is interpreted independently from the cementing operation. Thus, a bad "report card" is usually translated into a bad cement job, which is often not the case. This paper illustrates the value of integrating cementing with bond logging to give a clearer picture of the actual quality of the cement downhole. Logs should be used as a tool to understand the cement quality and determine what improvements need to be made to enhance cementing job success. Four examples are presented which show that factors such as 1) borehole conditions, 2) cement job design, 3) displacement practices and 4) tool selection and calibration all have an effect on the bond log interpretation. However, in all cases, integrating the log response with a thorough cement evaluation results in a more accurate analysis of the cement quality, and a better educated decision on the necessity for remedial work.