reacting {HEAD ~ the oxidant} and fuel in the oxidizers to produce heat to heat a portion of {TAIL ~ the formation}; and 
reacting { HEAD ~ the oxidant } and fuel in the oxidizers to produce heat to heat a portion of { TAIL ~ the formation } ; and
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH