High-pressure methane and carbon dioxide sorption on coal and shale samples from the Paraná Basin, Brazil

►CH4 and CO2 sorption measured on coal from first CBM well in Paraná Basin, Brazil. ►Sorption capacity up to 0.47 mmol/g for CH4 and up to 0.81 mmol/g for CO2. ►Significant CO2 sorption on mineral matter of high-ash coal and shale. ►CO2 storage potential estimated to be up to 15.4 Gt in 20 × 20 km2 study area.