Reliable cement evaluation is crucial for well integrity and optimal production. Current cement evaluation technologies have limitations and a fundamental analysis is performed to assess neutron logging for this purpose. Basic modelling has been performed to study neutron transmission for several realistic cases including good cement, channeled cement, foamed cement and through-tubing configurations. For a comprehensive review, other aspects such as health, safety and environment (HSE), cost and alternative approaches have also been assessed.
Results achieved show that neutrons have the potential to travel to the cement-formation interface and return to the detector without being completely attenuated. For single casing configurations, results indicate that cement channels produce distinguishable results from intact cement. For through-tubing logging it cannot be concluded that detected results are distinguishable. Even though neutron logging itself is likely to be more costly than cement bond logs, potential benefits in terms of other cost savings and decrease in HSE risks must also be considered.