Potential for heat production by retrofitting abandoned gas wells into geothermal wells Mehmood, Asif ; Yao, Jun ; Fan, Dongyan ; Bongole, Kelvin ; Liu, Junrong ; Zhang, Xu Abstract Publication: PLoS ONE Pub Date: August 2019 DOI: 10.1371/journal.pone.0220128 Bibcode: 2019PLoSO..1420128M