The objective of this project is to develop a better understanding of the performance of the casing-cement bond under HPHT well conditions leading to a model to predict well life.
Project Goals:
Description of the importance of cement fatigue to the life of HPHT wells
Lab procedures and prototype test cell to measure the performance of cement in cyclic loading under HPHT conditions
Model to predict life of HPHT wells
Recommendation for further work
Fatigue failure in cement occurs when microscopic damage within the microstructure of the cement, caused by initial cyclic loading, turns into macroscopic cracks under gradually increasing loads. Cyclic loading impacts initial damage and if loading is continued at load ratios above the critical ratio for a particular cement mix, failure is imminent, but may undergo many cycles when loaded below this ratio. Loading conditions may affect the fatigue property of cement only when the mechanical properties are such as to withstand static loading. Designs based solely on static loading conditions may or may not be enough to ensure long term integrity depending on prevailing down-hole conditions, thus the need to take the analysis further by also examining the effect of fatigue.