Model Uncertainties and Resolution Studies With Application to Subsurface Movement of a CO2 Injection Project in the Krechba Field Using InSAR Data

Surface deformation-based reservoir monitoring technologies, such as Tilt, GPS and Interferometric Synthetic Aperture Radar (InSAR), have been successfully applied to monitor fluid flow or pressure changes in the reservoir and fluid migration to shallow depths. Obtaining the subsurface fluid movement from the surface deformation requires performing a geophysical inversion. To get meaningful results from the inversion process requires diligent selection of the inversion method and reservoir block sizes, as well as the application of physically reasonable constraints. The focus of this paper is to provide a workflow and guidelines for field application by studying the inverse problem, the solution methods and associated error estimates for the unknown model parameters, and the resolving power for each parameter. As a field case demonstration, the methodologies are applied to a CO2 monitoring project with InSAR data. Also, the subsurface movement of CO2 will be presented.