Visualizing Uncertainty in CO2 Plume Migration During Sequestration

During the operation of a geological carbon storage project, verifying that the CO2 plume remains within the permitted zone will be of particular interest both to regulators and operators. A model selection algorithm was developed, which refines an initial suite of subsurface models representing the prior uncertainty to create a posterior set of subsurface models that reflect injection performance consistent with that observed. Such posterior models can be used to represent uncertainty in the future migration of the CO2 plume. The method provides a very inexpensive alternative to map the migration of the plume and the associated uncertainty in migration paths due to the fact that only injection data is required. An essential aspect of the model selection algorithm is to group prior models on the basis of their connectivity. The base algorithm assesses that connectivity using a physical proxy such as a random walker. An alternate approach would be to use statistical tools for assessing connectivity of models. In this paper, we present an approach to compute the shortest connected path between well locations in an aquifer model and to define a measure of similarity of shape based on the concept of a discrete Frechet distance.