Downhole tool including a two part drilling and running tool that couples its smaller assembly to a conveyance

A method, comprising:

• providing a downhole tool, the downhole tool including:
• a larger bit assembly having a first larger bit assembly end, a second opposing larger bit assembly end, a length (LLB), and an outer width (WLB), the first larger bit assembly end having a larger bit assembly coupling configured to engage with and axially fix to a conveyance coupling of a conveyance;
• and
• a smaller assembly having a first smaller assembly end, a second opposing smaller assembly end, a length (LSA), and an outer width (WSA), the smaller assembly at least partially positioned within the larger bit assembly, wherein the smaller assembly and the larger bit assembly form at least a part of a two part drilling and running tool;
• and
• retracting the smaller assembly within the larger bit assembly to form a combined bit assembly while the larger bit assembly is axially fixed to the conveyance.

A well system, including:

• a wellbore extending through one or more subterranean formations;
• and
• a downhole tool positioned within the wellbore, the downhole tool including:
• a larger bit assembly having a first larger bit assembly end, a second opposing larger bit assembly end, a length (LLB), and an outer width (WLB), the first larger bit assembly end having a larger bit assembly coupling configured to engage with and axially fix to a conveyance coupling of a conveyance;
• and
• a smaller assembly having a first smaller assembly end, a second opposing smaller assembly end, a length (LSA), and an outer width (WSA), the smaller assembly at least partially positioned within the larger bit assembly, wherein the smaller assembly and the larger bit assembly form at least a part of a two part drilling and running tool, the smaller assembly configured to retract within the larger bit assembly to form a combined bit assembly while the larger bit assembly is axially fixed to the conveyance.