Comparative study of laboratory and portable spot permeability measurements in bioturbated carbonate strata.

In bioturbated strata, defining and obtaining a representative elementary volume for permeability measurements presents significant challenges. To address this, spot permeability is often used as an alternative method to estimate the bulk permeability of these complex strata. However, laboratory measurements of spot permeability require steady-state nitrogen gas injection and careful sample preparation including slab cutting which makes the process both time-consuming and resource-intensive. Alternatively, field measurements using portable devices offer a more cost-effective, straightforward, and real-time approach for assessing permeability in situ. To evaluate the accuracy of portable devices in measuring spot permeability in bioturbated strata, we compare and contrast permeability measurements on the same rock samples (from the Hanifa Formation in central Saudi Arabia) using two different techniques: the sophisticated laboratory-based AutoScan system and the portable TinyPerm 3 field device both from New England Research (NER). Two sets of permeability data comprising 64 measurements were obtained and analyzed graphically using Whisker Box Plots, Bland-Altman Plot, Curve Matching, and Cross Plots, as well as statistically through correlation analysis and analysis of variance (ANOVA). The graphical analysis revealed no substantial difference in permeability measured by the two methods, a finding further supported by ANOVA results, which indicated no statistically significant difference (P-value > 0.05). Additionally, the correlation plot between the permeability measurements from the two methods yielded a straight line with an R[Formula: see text] value greater than 0.9, demonstrating a strong agreement. This study highlights the potential of using portable handheld permeameters to measure spot permeability of bioturbated strata in the field, offering a cost-effective, accurate, and real-time alternative to laboratory-based techniques in estimating their bulk permeability.