The application discloses a method suitable for
hydrogen production in situ in an oil reservoir underground, and belongs to the technical field of oil and gas development. The method comprises the following steps: arranging three
horizontal wells, i.e., upper, middle and lower
horizontal wells, and a temperature detection well in the same reservoir, the temperature detection well is used for detecting the temperature of the middle horizontal well, and a
hydrogen gas filter membrane is arranged at the upper horizontal well; a heating device is arranged at the middle horizontal well, a close
cutting volume fracturing is carried out around the well, and a
reaction zone is formed by filling a catalyst and a heat-conducting agent; in-situ ignition is carried out at the lower horizontal well, and an
oxygen-containing gas is injected, so that the
oxygen-containing gas is incompletely combusted to generate CO and CO2 and form a gasification zone; a heating device is used for heating to above 450 DEG C, when the gas in the gasification zone enters the
reaction zone,
water vapor is injected to carry out high-efficiency
hydrogen production; and the upper horizontal well is opened, and the hydrogen gas filter membrane is used for extracting hydrogen gas. The
hydrogen production block is separated, the underground
hydrogen production efficiency is greatly improved, the energy
utilization rate is improved, and therefore the method has good application value.