Figure 5.
Methanogenic pathways and biogenic methane production potential of deep shale-gas wells after hydraulic fracturing. a. The proposed methanogenetic pathways and related genes detected in shale-gas wells. Genes shown in red colour are involved in the hydrogenotrophic pathway, blue colour in the methylotrophic pathway, yellow color in the acetoclastic pathway. b. Quantification of dsrB and mcrA genes (bar), and methane generation (green dot) from produced water samples supplemented with deionized water (Control), acetate, methanol, H2 + CO2, and sodium molybdate (Molybdate) on the day of 110.