Prediction leakage channels of CO2 injection wells

During CO2 injection, a microannulus will be generated, leading to the transmission of gas through the cement behind the casing or before the formation when thermal stress exceeds bond strength. In this work, leakage channel prediction model was developed to predict the leakage channel of CO2 injection wells. The prediction results indicate that the thermal stresses first decreased and then increased with increasing well depth; decreased with increasing radial distance; and increased with increasing injection time. The cement sheath of a production casing is more likely to form a leakage channel than other cement sheaths during long-duration CO2 injection. (C) 2019 The Authors. Published by Elsevier Ltd.