When the displacement is finished, the valve on the on board storage tank will be closed and {HEAD ~ the pressure} in the annulus released back to {TAIL ~ the surge tank} 
released back to
When the displacement is finished , the valve on the on board storage tank will be closed and { HEAD ~ the pressure } in the annulus released back to { TAIL ~ the surge tank }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL