about 58 scf bbl water as a worse case assume cold water solubility to be similar so if 140 scf of co needs to be removed 2 4 bbls of water needs to be contacted and saturated this limit can be extended by changing oxygen steam ratios or by increasing system pressures in any case undissolved co should either be controllable or should not build up to levels that inhibit injectivity because co 2 need not be removed using separate vent wells or a segregated well section the preferred geometry for deep sagdox processes can be simplified to three preferred cases the basic sagdox process with twin horizontal wells 2 4 can be simplified by removing the vent gas 22 annulus in fig3 similarly the thsagdox version is also simplified as shown in fig3 the swsagdox version is also simplified as shown in fig3 some of the differences between the prior art sagdox and the sagdox for deep reservoirs include sagdox has at least one vent gas well to remove non condensable combustion gases sagdox for deep reservoirs does not require same the target is deep high pressure reservoirs gt 500 m average depth or gt 800 psia average pressure and non condensable gas preferably co 2 is dissolved in bitumen sagdox prefers venting of said gas no vent wells required to remove non condensable combustion gases pressure and oxygen steam ratios can be.