Milling assembly for drilling a multilateral wellbore

A system for creating a lateral wellbore from a parent wellbore, the system comprising:

• a whipstock to be positioned in the parent wellbore;
• a workstring to be positioned in the parent wellbore, wherein the workstring comprises a lead mill and a secondary mill positioned behind the lead mill along the workstring, wherein the whipstock is to deflect the workstring to drill the lateral wellbore into a casing of the parent wellbore through a mill window using the lead mill and the secondary mill;
• milling sensors to be positioned at at least two locations in the parent wellbore, wherein the at least two locations comprise the lead mill and a position along the workstring that is closer to a surface of the parent wellbore as compared to the lead mill;
• a processor;
• and
• one or more computer-readable media including instructions that, when executed by the processor, cause the processor to perform operations, the instructions comprising,
• instructions to monitor the deflecting based on sensor measurements of the milling sensors;
• instructions to determine a difference in a first value of a deflection attribute measured by a first sensor measurement of the sensor measurements at the lead mill and a second value of the deflection attribute measured by a second sensor measurement of the sensor measurements at the position along the workstring that is closer to the surface of the parent wellbore as compared to the lead mill, wherein the deflection attribute comprises at least one of torque, direction, force, strain, or vibration;
• and
• instructions to adjust the deflecting of the workstring based on the difference in the first value and the second value of the deflection attribute.

One or more computer-readable media including instructions that, when executed by one or more processors, cause the one or more processors to perform operations, the instructions comprising:

• instructions to receive data that comprises data from sensor measurements of milling sensors at at least two locations in a parent wellbore, wherein the at least two locations comprise the lead mill and a position along the workstring that is closer to a surface of the parent wellbore as compared to the lead mill, wherein the sensor measurements are to occur during deflecting of the workstring with a whipstock to drill a lateral wellbore through a milling window of a casing of the parent wellbore;
• instructions to determine a difference in a first value of a deflection attribute measured by a first sensor measurement of the sensor measurements at the lead mill and a second value of the deflection attribute measured by a second sensor measurement of the sensor measurements at the position along the workstring that is closer to the surface of the parent wellbore as compared to the lead mill, wherein the deflection attribute comprises at least one of torque, direction, force, strain, or vibration;
• and
• instructions to adjust the deflecting of the workstring based on the difference in the first value and the second value of the deflection attribute.