Shaft used for reducing heat loss

The utility model discloses a shaft used for reducing heat loss. The shaft comprises a casing and an oil pipe arranged in the casing in a penetrating mode, and the casing and the oil pipe extend into an oil layer from the ground. The shaft is characterized in that an annular space is formed between the casing and the oil pipe, the shaft further comprises a pithead element on the ground, the pithead element is provided with a first flow channel used for being communicated with the oil pipe and a second flow channel used for being communicated with the annular space, the first flow channel is spaced with the second flow channel, the shaft further comprises a packer arranged above the oil layer and located in the annular space and a steam and water separation device arranged above the packer, the steam and water separation device is provided with a first separation opening used for separating saturated water and a second separation opening used for separating dry steam, the first separation opening is communicated with the annular space, and the second separation opening is used for being communicated with the oil layer. By means of the structure, energy of the saturated water offsets heat loss of the shaft, so that steam energy in the shaft is protected, and steam injection quality and shaft bottom steam dryness are improved.