Single-shaft three-well surface layer drilling method adopting space-occupying drilling tool method

The invention discloses a single-shaft three-well surface layer drilling method adopting a space-occupying drilling tool method. The single-shaft three-well surface layer drilling method comprises thefollowing steps that S1, a 36-inch single-shaft three-well base plate is installed above a marine riser casing; S2, a derrick is sequentially moved to a well B and a well C, and space-occupying drilling tools are tripped into the well B and the well C respectively; S3, the derrick is moved to a well A, and well opening and cementing operation is conducted on the well A; S4, the height of the cement surface of the well A is determined by using a fishing line hanging measurement method; S5, the derrick is moved to the well B, and well opening and cementing operation is conducted on the well B;S6, the height of the cement surface of the well B is determined by using a fishing line hanging measurement method; and S7, the derrick is moved to the well C, and well opening and cementing operation is conducted on the well