The method 1, wherein {TAIL ~ about 0.005 to about 0.4 pore volumes} of solution containing a sacrificial agent is injected into {HEAD ~ the formation} 
The method 1 , wherein { TAIL ~ about 0.005 to about 0.4 pore volumes } of solution containing a sacrificial agent is injected into { HEAD ~ the formation }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD