Carbon capture and storage (CCS) projects are designed to be safe for humans and the environment. Plans and operations throughout the CCS project ensure the CO2 will stay within the geologic rock layer into which it is injected. Monitoring is an important part of every CCS project, planned and implemented before (baseline), during and after the injection phase. Operators monitor to fulfill obligations such as: locating the injected CO2 plume, re-evaluating Area of Review, and ensuring that potable water sources and ecosystems are protected throughout the lifecycle of the storage project.
Pre-Injection
Before the project begins, CCS scientists and engineers select only the best sites for safe, permanent CO2 storage. They predict lateral movement of CO2 in the storage zone and formulate the Area of Review. In addition, project managers must seek project approval from the proper regulatory authority to operate the storage facilities and inject CO2. The project plan must provide for safe injection and monitoring, leak detection and reporting, risk assessment and mitigation, and post-injection site care and closure. Monitoring design and potential baseline monitoring happens before injection.
Injection
During the injection phase, engineers must ensure correct injection pressure. They also must monitor for potential leaks and impacts to the environment per the permitted monitoring plan. Part of monitoring a project during injection is confirming that the CO2 is moving as predicted and is staying within the storage layer.
Post-injection
After the injection phase has ended, monitoring continues in order to ensure that the CO2 remains securely stored in the storage formation, and that there are no environmental effects from CCUS. Monitoring continues according to the permit plan until the CO2 stops moving.
We have previously discussed that tools are typically categorized as atmospheric, near-surface or subsurface. Let’s explore a few of these tools using our Monitoring Interactive.
Go to the interactive and click on the Surface Seismic Survey monitoring tool, read the intro, and then continue on to ‘learn more’ about this tool.
Why would a project have as part of its plan to collect multiple surface seismic surveys?
Multiple surveys conducted over time provide a means of tracking the progression of the CO2 plume in the reservoir.
Correct
Multiple surveys conducted over time ensure that the scientists can 'high-grade' their data and use the best data for analysis.
Incorrect
Multiple surveys conducted over time allow better imaging of thin zones.
Incorrect
Go to the interactive and click on the Surface Deformation monitoring tool, read the intro, and then continue on to ‘learn more’ about this tool.
InSAR is a satellite-based technique that measures millimeter-scale displacements of the Earth’s surface. What is one of the benefits of this type of tool over others?
InSAR methods work best in locations with complex terrain and varied conditions.
Incorrect
InSAR methods can track pressure changes or geomechanical impacts in the subsurface associate with CO2 plume migration.
Correct
InSAR methods respond to groundwater withdrawal and recharge in an area.
Incorrect
Go to the interactive and click on the Wireline Logs monitoring tool, read the intro, and then continue on to ‘learn more’ about this tool.
Why was pulsed neutron capture logging implemented to monitor the accumulation and migration of CO2 in depleted oil fields as part of a storage project in Michigan?
Pulsed Neutron Capture logs can expand the monitoring beyond the wellbore.
Incorrect
Pulsed Neutron Capture logs are not sensitive to water or oil saturation within the formation.
Incorrect
Use of conventional logging tools in existing wells to evaluate fluid saturations was problematic because those tools perform only in non-cased boreholes.
Correct
Go to the interactive and click on the Fluid Sampling monitoring tool, read the intro, and then continue on to ‘learn more’ about this tool.