| Loss of cased wellbore integrity can cause many significant problems, including lost production, aquifer contamination, blowouts, and other environmental damage. The objective of this study is to conduct an analysis of the Wabamun Area Sequestration Project (WASP) to determine if wells in that area are suitable for CO2 sequestration. This was done by conducting laboratory experiments on the common cement compositions found in the area, simulating the various conditions possible in a wellbore, and by analyzing three case studies from the WASP. The cases include two existing production wells and a proposed injection well specifically designed for CO2 sequestration. This study investigated multiple wellbore construction scenarios using a variety of parametric analyses and three case studies. The conditions that can affect leakage risk were simulated, including cement composition, experimentally derived mechanical and thermal properties, heat of hydration, shrinkage/expansion, pore pressure variations, injection thermal loading, and injection mechanical loading. Transient chemo-poro-thermo-elastic staged analytical models and staged finite element simulations were conducted for each of the scenarios and case studies. The results of the case studies found that existing wells can be repurposed to become CO 2 sequestration wells as long as the well is structurally sound before injection. There is a significant risk to the loss of cased wellbore integrity if the effects of a well's life are not taken into account. The model developed in this paper is useful to investigate the integrity for the wells in the WASP as well as other onshore and offshore wells. |
