Fig. 1: Map of study area showing locations of the Olla and Nebo-Hemphill oil fields as well as the Black Lake Oil Field, from which the injected CO2 was sourced.
From: Rapid microbial methanogenesis during CO2 storage in hydrocarbon reservoirs

Only the Olla Oil Field contains injected CO2. The inset on the right shows an expanded view with individual sample locations (nearby urban areas are denoted by stars) and a stratigraphic column showing the relevant lithologic units9.