Reliability of the cement bond log has been a controversial subject since its introduction in 1959. Degree of acceptance has varied widely not only between companies but also within companies. This paper describes how the reliability and economics of the cement bond log were evaluated for Mobil's New Orleans Producing operations. Completion and producing data from thirty-three (33) Louisiana offshore wells is used as the basis for statistical analysis. The primary factors considered are cement bond logging procedures, log interpretation, physical data of primary and/or secondary cementing, and well performance. It is concluded that
reliability of the cement bond log is above 90% when run and interpreted properly,
the full-wave recording type log is required, and
completion costs can be reduced by using the log in wells where a good bond is required for successful completion, especially in multiple zone wells.
