The injection of hydrogen is carried out under a pressure sufficient to cause the injected hydrogen to become absorbed within {HEAD ~ the matrix} of {TAIL ~ the carbonaceous formation} 
of
The injection of hydrogen is carried out under a pressure sufficient to cause the injected hydrogen to become absorbed within { HEAD ~ the matrix } of { TAIL ~ the carbonaceous formation }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL