Potential CO2 and brine leakage through wellbore pathways for geologic CO2 sequestration using the National Risk Assessment Partnership tools: Application to the Big Sky Regional Partnership

Journal Article · Fri Feb 01 00:00:00 EST 2019 · International Journal of Greenhouse Gas Control

DOI:https://doi.org/10.1016/j.ijggc.2018.12.002· OSTI ID:1489716

Onishi, Tsubasa; Nguyen, Minh C. ; Carey, J. William ; Will, Bob; Zaluski, Wade; Bowen, David W.; Devault, Bryan C.; Duguid, Andrew; Zhou, Quanlin; Fairweather, Stacey H.; Spangler, Lee H.; Stauffer, Philip H.

Geologic CO₂ sequestration (GCS) has received high-level attention from the global scientific community as a response to climate change due to higher concentrations of CO₂ in the atmosphere. However, GCS in saline aquifers poses certain risks including CO₂/brine leakage through wells or non-sealing faults into groundwater or to the earth's surface. Understanding crucial reservoir parameters and other geologic features affecting the likelihood of these leakage occurrences will aid the decision-making process regarding GCS operations. In this study, we develop a science-based methodology for quantifying risk profiles at geologic CO₂ sequestration sites as part of US DOE's National Risk Assessment Partnership (NRAP). We apply NRAP tools to a field scale project in a fractured saline aquifer located at Kevin Dome, Montana, which is part of DOE's Big Sky Carbon Sequestration Partnership project. Risks associated with GCS injection and monitoring are difficult to quantify due to a dearth of data and uncertainties. One solution is running a large number of numerical simulations of the primary CO₂ injection reservoir, shallow reservoirs/aquifers, faults, and wells to address leakage risks and uncertainties. However, a full-physics simulation is not computationally feasible because the model is too large and requires fine spatial and temporal discretization to accurately reproduce complex multiphase flow processes. We employ the NRAP Integrated Assessment Model (NRAP-IAM), a hybrid system model developed by the US-DOE for use in performance and quantitative risk assessment of CO₂ sequestration. The IAM model requires reduced order models (ROMs) developed from numerical reservoir simulations of a primary CO₂ injection reservoir. The ROMs are linked with discrete components of the NRAP-IAM including shallow reservoirs/aquifers and the atmosphere through potential leakage pathways. A powerful stochastic framework allows NRAP-IAM to be used to explore complex interactions among a large number of uncertain variables and to help evaluate the likely performance of potential sequestration sites. Using the NRAP-IAM, we find that the potential amount of CO₂ leakage is most sensitive to values of permeability, end-point CO₂ relative permeability, hysteresis of CO₂ relative permeability, capillary pressure, and permeability of confining rocks. In addition to demonstrating the application of the NRAP risk assessment tools, this work shows that GCS in the Kevin Dome has a higher probability of encountering injectivity limitations during injection of CO₂ into the Middle Duperow formation than previous studies have calculated. Finally, we estimate very low risk of CO₂ leakage to the atmosphere unless the quality of the legacy well completions is extremely poor.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC02-05CH11231; FC26-05NT42587
• OSTI ID: 1489716
• Alternate ID(s): OSTI ID: 1571966
• Journal Information: International Journal of Greenhouse Gas Control, Journal Name: International Journal of Greenhouse Gas Control Vol. 81 Journal Issue: C; ISSN 1750-5836
• Publisher: Elsevier
• Country of Publication: Netherlands
• Language: English

Related Subjects

58 GEOSCIENCES
Geologic CO2 sequestration
Uncertainty assessment
Risk assessment
Reservoir simulation
Design of experiment