System and method for controlling a drilling path based on drift estimates

A surface steerable system for use with a drilling rig comprising:

• a network interface;
• a processor coupled to the network interface;
• and
• a non-transitory memory coupled to the processor, the memory storing a plurality of instructions for execution by the processor, the plurality of instructions including:
• instructions for receiving, by a surface steerable system coupled to a drilling rig, BHA information from a bottom hole assembly (BHA) located in a borehole, wherein the BHA information corresponds to a first location of the BHA within a geological formation;
• instructions for determining, by the surface steerable system, whether the first location of the BHA is not within a predetermined amount from a target drilling path;
• instructions for receiving geological drift information for the geological formation indicating a trajectory bias within the geological formation observed while drilling along a straight path;
• instructions for calculating, by the surface steerable system, if the first location of the BHA is not within the predetermined amount from the target drilling path, a drift vector corresponding to the trajectory bias for the BHA within the geological formation, and a toolface vector or a convergence path from the first location of the BHA to the target drilling path that compensates for the drift vector such that the BHA will converge with the target drilling path by drilling in accordance with the toolface vector;
• instructions for causing, by the surface steerable system, at least one control parameter to be modified in order to alter a drilling direction of the BHA based on the calculated toolface vector;
• and
• instructions for transmitting the at least one control parameter to the drilling rig drill in accordance with the calculated toolface vector.

A drilling system, comprising:

• a bottom hole assembly (BHA) for drilling a borehole through a geological formation responsive to steering control signals;
• a drilling rig for driving the bottom hole assembly through a drill string;
• a surface steerable system for generating the steering control signals to control the BHA, wherein the surface steerable system (a) receives BHA information from the BHA wherein the BHA information comprises a first location of the BHA, wherein the first location is within a geological formation, (b) receives geological drift information for the geological formation indicating a trajectory bias within the geological formation observed while drilling along a straight path, (c) determines if the distance from a first location of the BHA to a target drilling path exceeds a predetermined amount and, if so, (d) calculates a drift vector corresponding to the trajectory bias for the BHA within the geological formation, and a toolface vector to create a convergence path from the first location of the BHA to the target drilling path that compensates for the drift vector, such that the BHA will converge with the target drilling path by drilling in accordance with the toolface vector, (e) causes at least one control parameter to be modified in order to alter a drilling direction of the BHA based on the calculated toolface vector, and (f) transmits the at least one control parameter to the drilling rig to drill in accordance with the calculated tool face vector.