(147d) Implementing and Validating Active Reservoir and Brine Management Strategies for the Enhancement of the Geologic Storage of Carbon Dioxide: An Update

The Energy & Environmental Research Center (EERC) is conducting a multiyear field demonstration to evaluate active reservoir management (ARM) strategies that have the potential to improve the commercial viability of the geologic storage of carbon dioxide (CO₂) by managing reservoir pressure, reducing stress on sealing formations, controlling the footprint of the injected fluid within a formation, and improving overall injection performance. This effort, the brine extraction and storage test (BEST), is being funded by the U.S. Department of Energy (DOE) National Energy Technology Laboratory, in partnership with Nuverra Environmental Solutions (Nuverra), Schlumberger, and Computer Modelling Group, and is being implemented at a field site located in North Dakota.

The BEST consists of two complementary components: 1) an ARM test and 2) a brine treatment test bed. Simultaneous injection and extraction of brine combined with a monitoring program will be used to evaluate ARM as a means of enhancing the geologic storage of CO₂ in a deep saline formation (DSF). The treatment of the formation fluids extracted as part of the ARM test will take place in a pilot-scale brine treatment test bed facility to investigate the capability of emerging water treatment technologies to treat high-salinity brine for beneficial use. Together, these two components will serve as a proxy for future saline CO₂ storage projects employing ARM to manage formation pressure plumes, subsurface CO₂ migration, and the extracted subsurface brine.

Phase 1 of the BEST project, which focused on final site selection and development of a field implementation plan, was completed in 2016 and yielded the following results:

• ARM testing will occur in the Inyan Kara Formation, a regionally extensive DSF previously identified as a prime target for commercial-scale CO₂ storage because of its superb geologic properties. This fact, combined with the presence of commercial brine injection operations at the Johnsons Corner site (Watford City, North Dakota) that emulate commercial-scale CO₂ storage (volumetrically equivalent to the injection of >250,000 tons/yr CO₂), makes the results of ARM in the Inyan Kara directly applicable to widespread adoption by carbon capture and storage (CCS) projects in DSFs.

• Recent and ongoing salt water disposal (SWD) operations at the Johnsons Corner site have created an ideal reservoir environment for conducting a BEST. Long-term operations at the site via two Class II underground injection control (UIC) injection wells have created a differential plume that can be modified through ARM, and the established injection history allows for confident simulated predictions.

• A four-well design, using the two existing SWD wells, provides operational flexibility and monitoring capability to test ARM scenarios through a range of injection and extraction rates. Injection can be independently controlled into both SWD wells, and the extraction rate, via a newly installed extraction well, can be varied. A new disposal well will also be installed into a lower geologic horizon for disposal of extracted water as a parallel to ARM implementation at CCS sites.

• While the native brine is expected to have salinities below 180,000 mg/L TDS, the produced water brines being delivered to the test site have a salinity typically greater than 300,000 mg/L TDS. Thus integration of the extracted brine treatment test bed facility with the operations of the Johnsons Corner SWD operations provides the ability to generate tailored brine concentrations and achieve the DOE target level of 180,000 mg/L TDS for the extracted brine treatment technology demonstrations.

Phase II of the project is now under way at the Johnson Corner site and consists of the execution of the field implementation plan, which comprises a site infrastructure design and implementation plan, a site operation plan, a monitoring plan, and a water treatment technology evaluation, design, and implementation plan. Currently, the necessary permits have been secured from the state of North Dakota and McKenzie County and the installation of an extraction well completed in the Inyan Kara Formation; an extracted brine disposal well completed in the Broom Creek Formation; and the brine test bed facility, brine-handling equipment (e.g., storage tanks, pipeline, etc.), and support infrastructure (e.g., additional power lines, access roads, etc.) are in progress. The brine test bed facility will provide a controlled environment to evaluate brine treatment technology performance for a range of beneficial use applications on a range of tailored brine compositions. Treatment rates ranging from 1 to 25 gallons per minute will be maintained over extended operating periods of 30 to 60+ days, with a desired minimum period sufficient to encompass a minimum of two maintenance cycles. Monitoring of all chemical and energy requirements will be performed along with the generation of all secondary residuals, sufficient to close a system energy and material balance.

The selection of the brine treatment technologies for Phase II testing is under way using a screening and selection process developed during Phase 1. This process consists of a scoring system that weights the areas of treatment cost, readiness level, safety considerations, and waste generation on a scale of 1 to 10. The selection process will give priority to those technologies associated with DOE-funded projects awarded for the development of innovative high-TDS (total dissolved solids) brine pretreatment and desalination technologies (DOE Funding Opportunity Announcements 0001095 and 0001238) that successfully satisfy technology screening criteria.

This presentation will provide an overview of the BEST Phase 1 project results and an update of the status of the Phase II ARM and brine treatment technology tests.