Abstract: In the technique of dual-string steam injection in hori- zontal well,the steam is injected through internal and exter- nal strings at the forward end and the dead end,with the double four channels and the double hangers as matching rig tool.Meanwhile,the equal-dryness dispenser is used to control the steam flow rate in the dual strings and to distrib- ute the dryness,with the thermal insulation mode as nitro- gen insulation.The successful manufacturing of dual-string steam injection suggests that the technique can be used to dynamically adjust the steam injection flow,thus increasing the availability of steam injection.