HR: 1340h
AN: H33F-0531    [Abstracts]
TI: Coupled Fluid-Heat Flow Model Analysis to Explain the Origin and Accumulation of Subsurface Carbon Dioxide: McElmo Dome Case Study
AU: * McPherson, B J
EM: brian@nmt.edu
AF: Hydrology Program, New Mexico Institute of Mining and Technology, Socorro, NM 87801 United States
AU: Heath, J
EM: jheath@nmt.edu
AF: Hydrology Program, New Mexico Institute of Mining and Technology, Socorro, NM 87801 United States
AU: Han, W S
EM: wshan@nmt.edu
AF: Hydrology Program, New Mexico Institute of Mining and Technology, Socorro, NM 87801 United States
AU: Koonce, J
EM: jkoonce@nmt.edu
AF: Hydrology Program, New Mexico Institute of Mining and Technology, Socorro, NM 87801 United States
AB: McElmo Dome contains a very large reservoir of natural carbon dioxide. Located within the Paradox Basin, southwestern Colorado, McElmo is among several large carbon dioxide reservoirs in the southwestern U.S. Estimates of total carbon dioxide in the reservoir exceed 2 gigatons, and over 14 megatons are piped annually from McElmo to petroleum fields in the west Texas Permian Basin, for enhanced oil recovery operations. This and other carbon dioxide accumulations in the region have been the subject of many studies since the 1930s, with several hypotheses offered for the origin of McElmo's carbon dioxide. The most cited explanation is thermal degradation of the Mississippian Leadville Formation, a carbonate system that extends over much of the western U.S. The Ute Mountain laccolith is only a few miles from McElmo. This large igneous intrusion penetrates the Leadville carbonates at McElmo, providing the setting for the thermal degradation mechanism. The purpose of this study is to evaluate quantitatively this conceptual model of carbon dioxide origin. We developed mathematical simulation models of coupled heat and fluid flow of the McElmo system. Thermal data suggest that temperatures were probably sufficient for thermal degradation (metamorphism) to generate carbon dioxide. However, uncertainties associated with the intrusion's properties and timing hinder efforts to evaluate whether other mechanisms may play a significant role as well. For instance, coupled fluid-heat flow history model results suggest carbon dioxide may also have been generated as a byproduct of hydrocarbon catagenesis in Mississippian strata.
DE: 8130 Heat generation and transport
DE: 1829 Groundwater hydrology
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting