providing {TAIL ~ fuel}, via a fuel conduit, to a plurality of oxidizers coupled in series in an opening in the formation, wherein an oxidizer that first receives fuel from {HEAD ~ the fuel conduit} is a first oxidizer 
providing { TAIL ~ fuel } , via a fuel conduit , to a plurality of oxidizers coupled in series in an opening in the formation , wherein an oxidizer that first receives fuel from { HEAD ~ the fuel conduit } is a first oxidizer
OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 HEAD OTH OTH OTH OTH