471125 Lessons Learned in Near-Surface Monitoring for Large-Scale CO2 Storage

Thursday, November 17, 2016: 9:58 AM
Van Ness (Hilton San Francisco Union Square)
Leroux Kerryanne M., Kyle A. Glazewski, Nicholas S. Kalenze, Barry W. Botnen, Daniel J. Stepan, Ryan J. Klapperich and John A. Hamling, Energy & Environmental Research Center, University of North Dakota, Grand Forks, ND

A 5-year near-surface monitoring program was developed and conducted by the Energy & Environmental Research Center as part of the Plains CO2 Reduction Partnership’s large-scale (>1,000,000 tons CO2/yr injection) CO2 storage demonstration site. The purpose of the program was to establish baseline (preinjection) conditions and variability of surface water, soil, and shallow groundwater aquifer chemistries in the vicinity of geologic CO2 injection that can be used in conjunction with continued assurance monitoring to 1) provide a scientifically defensible source of data to show that near-surface environments remain unaffected by fluid or gas migration and 2) identify and evaluate anomalies that could be indicative of an out-of-zone migration event should they occur during assurance monitoring. 

The near-surface monitoring program implemented consists primarily of acquisition and analysis of soil gas and water chemistry data. This program comprised three parts: sampling of surface water features, sampling of shallow groundwater aquifers, and sampling of soil gas in the shallow vadose zone. Assessment of the analysis data indicated that a high degree of natural variability within these systems is possible, especially at select sampling locations. However, the techniques proved to generate sufficient data to both detect and attribute anomalies to natural processes within these environments.

The lessons learned from execution of the program encompass proper establishment of baseline site conditions, effective and efficient assurance monitoring following the start of CO2 injection operations, and critical data management of monitoring results. Baseline activities included site characterization and reconnaissance, establishment of sampling locations and techniques, and evaluation of results to determine natural variation. Assurance monitoring allowed for protocols to be developed to address any potential anomaly detection and for prioritizing near-surface sampling frequency, types of samples and analyses conducted, and client/landowner relations. Data management required strict organization in preserving raw data, processing data during evaluation, and database development for housing and accessing results. Extensive quality assurance/quality control practices were also developed and integrated throughout all aspects of the monitoring program. The methodology developed and lessons learned will allow future carbon capture, utilization, and storage operators to make informed decisions regarding site-specific monitoring programs at other commercial-scale injection sites throughout the region.    

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