Composition and Origin of Surface Casing Fluids in a Major US Oil- and Gas-Producing Region.

ABSTRACT: Fluids leaked from oil and gas wells often originate from their surface casing─a steel pipe installed beneath the deepest underlying source of potable groundwater that serves as the final barrier around the well system. In this study, we analyze a regulatory dataset of surface casing geochemical samples collected from 2573 wells in northeastern Colorado─the only known publicly available dataset of its kind. Thermogenic gas was present in the surface casings of 96.2% of wells with gas samples. Regulatory records indicate that 73.3% of these wells were constructed to isolate the formation from which the gas originated with cement. This suggests that gas migration into the surface casing annulus predominantly occurs through compromised barriers (e.g., steel casings or cement seals), indicativ

SUBMITTER: Lackey G 

PROVIDER: S-EPMC9731267 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature