The invention discloses a radial horizontal
drilling system using
supercritical carbon dioxide and a drilling method thereof. The
drilling system comprises a
liquid carbon dioxide supplying device, a drilling device, an in-well
pressure control device, a
solid, liquid and gas three-phase separating device and a
carbon dioxide recycling device, wherein the drilling device is arranged in a shaft, and includes an oil
pipe, a steering gear mounted at the bottom of the oil
pipe, and a flexible
drill stem sleeved in the oil
pipe; the flexible
drill stem passes through the steering gear and then realizes steering; the flexible
drill stem has a hollow drill stem channel; a
supercritical carbon dioxide jet drill is mounted at the end of the part, in a horizontal direction, of the flexible drill stem; a
nozzle, which is communicated with the drill stem channel, is formed on the jet drill; the in-well
pressure control device is disposed at the opening of a well; the
solid, liquid and gas three-phase separating device and the
carbon dioxide recycling device are disposed on the ground. The radial horizontal
drilling system disclosed by the invention uses
supercritical carbon dioxide fluid as
rock breaking fluid, thus avoiding
pollution to oil reservoir
layers, effectively protecting the oil reservoir
layers, greatly increasing
rock breaking efficiency, and realizing cyclic utilization of the
carbon dioxide; and the radial horizontal drilling
system using supercritical carbon dioxide and the drilling method thereof have important application value to increase of production of old wells and to development of
unconventional oil-gas reservoir.