De-risking carbon sequestration projects with comprehensive reservoir monitoring

As industries worldwide continue to decarbonize their operations on the way to net zero, the development of carbon storage, or sequestration, is accelerating. According to the Global CCS Institute, the combined, announced capacity of carbon capture and storage (CCS) projects in some stage of development or construction has grown by more than 50% every year since 2020, with an estimated 392 projects worldwide in the development pipeline, as of July 2023.¹  

Designing, building, and cost-effectively managing these projects requires a robust de-risking plan. Project de-risking is essential to ensuring reliable, secure carbon dioxide (CO2) storage for the anticipated 20-to-30-year life of a project. It also ensures that the operator meets its long-term business objectives, minimizes its operating expenses, and satisfies the demands of several stakeholders: 

• Neighboring communities demand transparency, that the injected CO2 is stored securely throughout the project’s operating life.  
• Regulators require that the storage site comply with rules governing the monitoring and reporting of CO2 injected and stored in subsurface formations.  
• Project investors seek risk reduction through technologies that ensure the project will operate safely and reliably for the long term. 

Reducing storage risks with long-term monitoring, measurement and verification. Detailed evaluation of a potential carbon storage site is crucial to assessing its long-term performance and viability to achieve the operator’s goals. Such an evaluation provides a deeper understanding of the complexities of identifying, analyzing and addressing the long-term requirements of carbon storage sites.  

Baker Hughes has developed a comprehensive monitoring, measurement, and verification (MMV) planning process that helps operators address the unique properties of every carbon sequestration project. The process includes decades of application expertise in subsurface evaluation and modeling, formation evaluation, integrated software solutions, and long-term monitoring technologies. With this robust MMV offering, operators can proactively manage risks, confirm well and reservoir integrity, reduce operating expenses (OPEX), satisfy regulatory requirements, and optimize long-term project management.  

The MMV process leverages the industry’s widest range of advanced, passive monitoring technologies to verify reservoir integrity and confirm that the injected CO2 stays safely contained for the project's life. Application experts draw on years of monitoring experience to select the optimal set of passive monitoring systems for a given site’s injection and long-term storage requirements.  

Experts begin the selection process at the prefeasibility stage of project development, leveraging their knowledge to perform detailed assessments of storage performance, evaluate the most cost-effective models for site injection, and ensure that the MMV plan complies with geological storage regulations.  

The selection process includes a cost/benefit analysis to ensure that any proposed monitoring technology delivers the most value for the project’s long-term injection and monitoring goals while minimizing OPEX. This analysis helps the operator optimize the design and installation of the project’s equipment and infrastructure—both in the subsurface and at the surface. The MMV process also streamlines engineering iterations to the final investment decision (FID), saving time and costs without increasing risk or compromising safety.  

The site’s monitoring technologies are linked through a digital ecosystem designed to handle the uncertainties, sensitivities, and nuances of CO2 storage analysis. During site operation, a digital integration platform incorporates data from multiple monitoring sources—including logging tools, fiber optics systems, and subsurface gauges—for a multi-faceted interpretation of subsurface conditions and seismicity. Real-time data analytics and advanced processing help detect low signal-to-noise ratio microseismic events and screen out background noise. A digital traffic light warning system uses real-time seismic data to provide both audible and visual warnings of a downhole event exceeding predetermined conditions. The data sets are presented in a visual format that allows the operator to respond to an alarm, make informed decisions based on the current conditions, and take proper corrective action to mitigate any risks.  

This unique combination of real-time monitoring, OPEX reduction, and digitally driven optimization has helped operators around the world de-risk their MMV programs and ensure the long-term integrity of sequestration projects.   

Ensuring long-term storage integrity with permanent monitoring arrays. An operator in southwestern France conducted a pilot project to capture and store CO2 from an industrial power plant in Lacq, with injection occurring near the town of Rousse and several kilometers from an old gas field. A lithology survey of the area pinpointed a dolomitic formation in the Rousse reservoir as a suitable site for the sequestration pilot. The reservoir contained a horst bordered by normal faults and was heavily depleted, which raised the risk of geomechanical instability.  

The site was only 2 km (1.24 mi) away from the Meillon/Saint-Faust fault and was in close proximity to population centers. Neighboring communities voiced concerns about the pilot plant’s safety and its potential for creating damaging seismic events. As a result, the regulatory authority charged with approving the project closely scrutinized the permitting process and required the operator to continually monitor reservoir seal integrity and seismic activity over a six-year period.  

The operator asked Baker Hughes to develop a reservoir monitoring plan that satisfied regulatory requirements. The service company simulated seismic source propagation to predict the optimal monitoring configuration. The company also drew upon its decades of field execution experience to select and install the optimal permanent seismic recording equipment.  

The proposed multi-scale monitoring solution included a regional network of geophones installed at a depth of 4,400 m (14,436 ft) to monitor reservoir and regional seismicity. The solution also included a highly sensitive, shallow-buried geophone array installed at 200 m (656 ft) near the injection site to monitor long-term injection processes. This combined solution would allow the operator to simultaneously monitor caprock integrity and fault reactivation for 30 years or more, with minimal operating costs. 

The monitoring system provided real-time data to update and refine the reservoir model. The data also afforded an early warning of any events that may be associated with induced seismicity, enabling appropriate mitigation measures to be implemented.  

Prior to injection, the reservoir monitoring solution characterized the natural seismicity of the reservoir and surrounding region. Documenting the baseline seismic activity of the area gave the operator critical supporting evidence to help discern between naturally occurring events and future potential induced seismicity from injection operations. 

Once the sequestration project commenced, the regional network of deep geophone arrays detected seismic activity within the storage reservoir during injection, but it confirmed that the caprock maintained integrity at all times, Fig. 1. The network also confirmed that any seismic activity on the pre-existing local fault was not caused by CO2 injection.  

Fig. 1. A map of microseismic events located with the regional SBA and borehole networks. Most data collected from the regional network were outside the expected injection zone. Much of these data were found to lie on a neighboring fault existing on the perimeter of the network.

The consistency and reliability of the results allowed the operator to continue injecting CO2 in the culturally sensitive area with greater confidence. Over the six-year pilot period, the reservoir monitoring solution achieved the operator’s goals for proper risk management, community assurance, and injection volume while maintaining subsurface integrity. 

Improving subsurface CO2 monitoring with autonomous stations advances. As the pace of CO2 sequestration project planning accelerates, Baker Hughes continues innovating to lower the risks, costs and uncertainty of long-term CO2 monitoring. The latest development, the CarbonWatch autonomous CO2 monitoring service, combines an array of monitoring stations and field-proven sensors to capture a wide range of field measurements—without an intervention operation and at 30% lower OPEX than traditional measurement techniques.  

Subsurface data are collected, analyzed and mapped in near-real time to assure operators that their reservoirs safely contain CO2 while conforming to regulatory requirements. By providing continuous insights from the site’s existing digital ecosystem, the service helps operators respond to anomalous monitoring measurements with greater speed and accuracy.   

Ultimately, ongoing monitoring advances like this will help operators achieve new levels of operational efficiency and risk management to meet their business objectives while providing local communities, regulators, and investors with the peace of mind of safe and durable CO2 storage. 

REFERENCE 

1. Global CCS Institute, “Global Status of CCS 2023,” https://www.globalccsinstitute.com/wp-content/uploads/2023/11/GSR23-Executive-Summary_PDF.pdf