Method and apparatus for transitioning between rotary drilling and slide drilling while maintaining a bit of a bottom hole assembly on a wellbore bottom

A method of transitioning from slide drilling to rotary drilling while maintaining a bit on a wellbore bottom, which method comprises:

• (a) identifying an off-bottom rotating hook load;
• (b) lowering the bit to the wellbore bottom;
• (c) performing slide drilling at a first hook load while the bit remains on the wellbore bottom;
• (d) reducing the first hook load to a target hook load while the bit remains on the wellbore bottom;
• (e) rotating drill string at an introductory RPM while the bit remains on the wellbore bottom;
• (f) lowering drill string to reach an introductory WOB while the bit remains on the wellbore bottom;
• and
• (g) performing rotary drilling at introductory WOB and introductory RPM while the bit remains on the wellbore bottom.

An apparatus adapted to transition a bit of a bottom hole assembly from a rotary drilling operation to a slide drilling operation while maintaining the bit on a wellbore bottom, the apparatus comprising:

• a non-transitory computer readable medium having stored thereon a plurality of instructions, wherein the instructions are executed with at least one processor so that the following steps are executed:
• (a) recording a first measured toolface value of the bottom hole assembly, wherein the bottom hole assembly is coupled to a drill string;
• (b) identifying a correlation between the first measured toolface value and a first quill position of a quill coupled to the drill string;
• (c) identifying a breakover torque for the drill string;
• (d) performing rotary drilling;
• (e) recording a second measured toolface value while the bit remains on the wellbore bottom;
• (f) receiving, while the bit remains on the wellbore bottom, a target toolface value;
• (g) calculating, while the bit remains on the wellbore bottom, an unwind amount to unwind the drill string;
• and
• (h) unwinding the drill string by the unwind amount to bring the second measured toolface value closer to the target toolface value while the bit remains on the wellbore bottom.