In-situ combustion layered ignition method

The invention provides an in-situ combustion layered ignition method. The method includes the steps that a casing pipe is landed into an oil well and extends to the well bottom; a thermal insulation pipe is landed into the casing pipe and a first annular space is formed between the thermal insulation pipe and the casing pipe; the first annular space is sealed through a first packer and a second packer, so that an upper-layer gas injection space and a lower-layer gas injection space are formed; an upper-layer gas distribution device located in the upper-layer gas injection space is arranged on the thermal insulation pipe; a Pupin oil pipe is landed into the thermal insulation pipe, a second annular space is formed between the Pupin oil pipe and the thermal insulation pipe, and an enhanced heat transfer device is arranged in the second annular space; an electric ignition device is landed in an inner cavity of the Pupin oil pipe; air is injected in the inner cavity and the second annular space and nitrogen is injected into the first annular space; the electric ignition device is started; heated gas in the thermal insulation pipe is injected into the upper-layer gas injection space through the upper-layer gas distribution device and an upper oil layer is heated and ignited; heated gas in the Pupin oil pipe is injected into the lower-layer gas injection space through the tail end of the Pupin oil pipe and a lower oil layer is heated and ignited.