Fig. 4: National estimate of low production well site CH4 emissions.
From: Methane emissions from US low production oil and natural gas well sites
a Comparison with Alvarez et al.16 assessment of total national CH4 emissions from all O&G production sites (Low prodn. = low production sites). Error bars represent the 95% confidence intervals (Methods). The blue bubbles represent the production-normalized CH4 loss rates for low production well sites (this study) and for all O&G sites16. b Regional estimates of low production well site CH4 emissions (see Fig. 1), with error bars representing the 95% confidence intervals on the mean (Methods). “Other” means total estimates for sites in other locations outside of regions 1–5 in Fig. 1. Symbols are sized by CH4 loss rates relative to gross CH4 production in each region, which are shown as % against each symbol. c Modeled distribution of mean site-level CH4 emissions (brown lines) and CH4 loss rates (blue lines). The thick solid lines represent the mean distribution while the thin lines are the results of the 500 simulated distributions for uncertainty assessment (Methods). For visualization, results are shown for the 99% of sites with modeled site-level emissions of up to 100 Mg/year and 100% CH4 loss rates. Additional results in tabular form can be found in Supplementary Tables 5–7. 1 Mg = 1000 kg.
