At least one common well is used for recovery of methane from the formation and introduction of {HEAD ~ hydrogen} into {TAIL ~ the formation} 
At least one common well is used for recovery of methane from the formation and introduction of { HEAD ~ hydrogen } into { TAIL ~ the formation }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL