Probabilistic Determination of the Role of Faults and Intrusions in Helium‐Rich Gas Fields Formation

Halford DT, Karolytė R, Andreason MW, Cathey B, Cathey M, Dellenbach JT, Cuzella JJ, Sonnenberg SA, Cheng A, McCaffrey KJW, Gluyas JG, Ballentine CJ

Natural gas fields with economic helium (>0.3 He %) require the radioactive decay of crustal uranium (U) and thorium (Th) to generate He and tectonic/structural regimes favorable to releasing and concentrating He. An unknown is determining the role of faults and structural features in focusing deep‐seated He sources on shallow accumulations. We tested the correlation between high‐He wells (n = 94) and structural features using a new high‐resolution aeromagnetic survey in the Four Corners area, USA. A depth‐to‐basement map with basement lineaments/faults, an intrusion map, and a flattened basement structural high map were created using Werner deconvolution algorithms by combining magnetic, gravity, and topography data with magnetic and gravity depth profiles. We show quantitatively (via analysis of variance) that a non‐random process controls the relationship between He (>0.3%) and both basement faults and intrusions: 88% of high‐He wells occur

Keywords:

geochemistry

,

intrusions

,

faults

,

geophysics

,

helium exploration

,

statistics