Distinguishing drilling-induced artifacts from naturally occurring hydrogen in soil gas surveys: Insights from sub-circular depressions

Natural hydrogen is emerging as a promising low-carbon energy source. However, its detection remains challenging due to the difficulty of distinguishing naturally occurring hydrogen from drilling-induced artifacts. This challenge is particularly evident in sub-circular depressions (SCDs), which are often the focus of exploration. This study investigates whether SCDs exhibit consistent areal patterns in soil properties and how they influence drilling-induced hydrogen artifacts in soil gas surveys. Soil properties were measured across 24 SCDs in the Yilgarn Craton and Perth Basin, Western Australia. In total, 83 holes were drilled for hydrogen soil gas analysis, with repeated measurements performed without redrilling. Drilling induced hydrogen artifacts were measured at up to 464 ppm in 85% of locations, primarily in high-strength, low-moisture soils, while only 15% represented naturally occurring hydrogen. Consistent patterns in soil properties correlated with artifact generation. Refined sampling techniques, including repeated measurements and expanded soil property analysis, are essential for distinguishing genuine hydrogen seepage from artifacts, enhancing exploration accuracy. • 85% of hydrogen anomalies measured in this study interpreted as drilling-induced artifacts. • High-strength, low-moisture soils are prone to artifact hydrogen generation during drilling. • Soil property measurements enhance interpretation of natural vs. drilling-induced hydrogen. • Sub-circular depressions show consistent soil strength and moisture patterns.