Vol 2 Chapter 3: Natural CO2 Fields as Analogs for Geologic CO2 Storage
Scott H. Stevens
Abstract: Our study evaluated three underground gas fields in the USA that have been effective CO2 traps for millions of years: the Jackson, McElmo, and St. Johns Domes. Together, these fields stored 2.4 billion t of CO2, equivalent to more than 1 year of USA power plant emissions. Because CO2 in these fields has been commercially extracted for industrial uses, the fields offer data on natural CO2 reservoirs, cap rocks, and production operations. M0cElmo Dome, the largest and most important field, originally stored 1.6 billion t of supercritical CO2 within a carboniferous carbonate reservoir at a depth of 2300 m. Carbon isotope data indicate the CO2 originated from a nearby igneous intrusion dated to 70 Ma. Its cap rock is a 400-m thick sequence of salt (halite), which is finely layered and unperturbed by faults which cut the underlying reservoir; there is no evidence of CO2 leaking into the overlying strata. McElmo Dome has two decades of safe operational history. It currently produces 15 million t/year (800 MMcfd) of 99%-pure CO2, which is transported 900 km via pipeline to depleted oil fields for re-injection and enhanced recovery. However, the three fields in our study represent a small sampling of geologic situations, insufficient for defining universal criteria for cap rock integrity. Building scientific and public acceptance for geologic CO2 storage may be facilitated if proposed projects each had a local or regional natural analog.
Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture
Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA
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