Carbon Dioxide in the Subsurface of Northeastern New Mexico
— Ronald F. Broadhead

Two naturally occurring subsurface accumulations of carbon dioxide (CO₂) gas, the Bravo Dome field and the Des Moines field, have been discovered in northeastern New Mexico. The Bravo Dome field is located on Bravo Dome, a southeast-plunging extension of the Sierra Grande Uplift. The field is formed by a combination of structural and stratigraphic elements with the Tubb Sandstone (Permian) as the main reservoir. Cumulative production is 3.3 trillion ft³ (TCF) CO₂, which is used almost entirely for enhanced oil recovery in the Permian Basin. Isotopic studies by several workers indicate the CO₂ originated in the mantle. Age dates of extrusive basalts in the Bravo Dome area appear to bracket the timing of basaltic magmatism and major CO₂ emplacement to between 1.46 and 5.29 Ma. The Des Moines field is located near the axial crest of the Sierra Grande Uplift. It is a small accumulation that produced CO₂ from Abo (Permian) sandstones and was abandoned circa 1966. Exploratory wells drilled elsewhere on the Sierra Grande Uplift have encountered shows of CO₂ and indicate the uplift is a CO₂ province and not a hydrocarbon province. The wide distribution of CO₂ and presence of CO₂ updip of confining seals in the Bravo Dome field require either multiple migration pathways from the mantle or widespread seepage from deep magmatic sources. Gases in adjacent basins are dominantly hydrocarbon except where reservoirs are associated with Tertiary-age intrusives or are not stratigraphically associated with petroleum source rocks.