Multi-outer-diameter coiled tubing oil and gas well shaft operation method

The invention relates to the technical field of oil-gas field development downhole operation methods, in particular to a multi-outer-diameter coiled tubing oil-gas well shaft operation method which comprises the steps that (1) according to coiled tubing optimization criteria, a coiled tubing combination is selected according to the trafficability of an operation shaft; (2) a blowout preventer group configuration method, wherein the blowout preventer group configuration mode is related to the outer diameter specification type of the continuous oil pipe, and N sections of continuous oil pipe combinations with different outer diameter specifications are provided with N matched blowout preventer groups; and (3) after the continuous oil pipe combination and the blowout preventer group are determined, the butt joint process of the continuous oil pipes with different pipe diameters is carried out. According to the invention, the continuous oil pipe efficient operation of an ultra-deep and variable-diameter shaft (a