System and method for placement and retrieval of a subsurface diverting tool used in drilling and completing wells

摘要

A diverting tool having a deflecting surface is equipped with an anchor that secures the tool at a desired subsurface location within the casing of a primary well bore to divert drilling equipment used to drill a lateral bore. An annular cup-type seal on the tool seals with the casing. A passage through the tool permits fluid bypass across the seal as the tool is lowered through the casing. The passage is closed from the well surface when the tool is anchored. After the lateral bore is drilled, the tool is used to divert a liner into the lateral bore. The upper end of the liner extends into the casing where it is centralized. The liner is cemented in the lateral bore and in the casing with the cement placed to effect sealing of the intersection of the liner and casing. A tubular mill removes the cement and liner from the casing above the diverter tool leaving a flush opening from the casing into the liner. The mill then telescopes over the deflecting surface, mills the swab-cup seal to disrupt the tool's seal with the casing, locks on to the tool and releases the tool from the casing for retrieval of the combined assembly to the well surface. The tool may be repositioned within the casing to divert tools into the liner.