Trajectory control for directional drilling using azimuthal gamma ray measurements

A system comprising:

• a processor;
• and
• a non-transitory memory device communicatively coupled to the processor comprising instructions that are executable by the processor to cause the processor to perform operations comprising:
• receiving a real-time azimuthal gamma log;
• generating an inverse model using at least one drilling parameter, the real-time azimuthal gamma log, and a formation model;
• generating actual formation gamma-ray activity using the inverse model;
• and
• outputting a command using the actual formation gamma-ray activity for steering a drill bit in directionally drilling a wellbore through a subterranean formation;
• receiving at least one drilling parameter, tool characterization parameter, and a formation model;
• generating a forward model of a tool response at a bed boundary using the at least one drilling parameter, the tool characterization parameter, and the formation model;
• predicting at least two gamma logs using the forward model;
• determining that a difference between the at least two gamma logs generates a confidence level that is greater than a confidence threshold;
• in response to determining that the difference between the at least two gamma logs generates a confidence level that is greater than the confidence threshold, generating a well plan;
• and
• wherein steering the drill bit is performed using the well plan.

A non-transitory computer-readable medium that includes instructions that are executable by a processing device to perform operations comprising:

• receiving at least one drilling parameter, tool characterization parameter, and a formation model;
• generating a forward model of a tool response at a bed boundary between a target formation and a neighboring formation using the at least one drilling parameter, the tool characterization parameter, and the formation model;
• predicting at least two gamma logs using the forward model;
• determining that a difference between the at least two gamma logs generates a confidence level that is greater than a confidence threshold;
• and
• in response to determining that the difference between the at least two gamma logs generates the confidence level that is greater than the confidence threshold, generating a well plan.