Activities
Modeling groups engaged in Sim-SEQ will have regular meetings, mostly via web-based teleconferences, but also workshops. These Sim-SEQ Technical Team meetings are organized and facilitated by LBNL. The meetings (1) focus on recent model results presented from one or two groups, (2) provide for model assessment via performance metrics for both MSA and MMA, and (3) lead to discussions about model improvements and lessons learned. The objective is to have fruitful cooperative discussions among the different groups emphasizing the common goal of improving model predictions. In preparation for these meetings, the LBNL team will monitor the ongoing activities and extract relevant information from reports as well as from direct discussion with the modeling groups and the Sim-SEQ Technical Team. Review of the chosen modeling approaches includes, for example, an assessment of the codes used and their capabilities, the type of site characterization data that have been available to develop the model, the processes that are included in the simulation, the simplifications that have been made, the main uncertainties and challenges, etc. The LBNL team will conduct timely review and evaluation of model results in comparison with measurements and results from other modeling groups.
Performance Metrics
Model performance metrics and acceptance criteria need to be defined to form an objective model evaluation framework for comparison of simulation results with measurements (and for inter-comparison between modeling results). The LBNL team will develop an initial list of metrics to be discussed and revised bythe Sim-SEQ Technical Team. Performance metrics and acceptance criteria may be defined for:
- migration of the CO2 plume as a function of time
- trapping mechanisms such as solubility trapping, residual trapping
- evolution of injection pressure and injectivity assessments
- large-scale evolution of pressure within reservoir and above it
- brine displacement and changes in salinity
- stress changes and induced seismicity, land surface uplift
- geochemical changes (gas and brine chemistry, precipitation, dissolution)
An example of a performance metric for plume migration would be the observed and simulated breakthrough of CO2 at an observation well, or the observed plume evolution from seismic profiles compared to the simulated plume evolution. While a general set of metrics can be developed, this general set will need to be aligned with the specifics of each site, as well as with the monitoring activities conducted there.
In the MSA, the predicted site behavior will be judged in comparison with the measured site behavior, and the specified performance metric will be used to judge the agreement between model and data, as well as to evaluate possible model improvements. In the MMA, the different models can be compared not only to the measured data, but also with each other. The latter has the advantage that performance metrics may be compared independent of the actual field measurements; i.e., the impact of certain model or parameter choices can be evaluated.