Systems and methods for sensorless state estimation, disturbance estimation, and model adaption for rotary steerable drilling systems

A rotary steerable drilling system exhibiting a state, comprising:

• a system simulator comprising a mathematical model of the rotary steerable drilling system, the mathematical model usable by a processing unit to generate an estimated output and an estimated state of the rotary steerable drilling system in response to a control input to the rotary steerable drilling system and without a sensing device in the rotary steerable drilling system to directly measure the state;
• a simulator controller configured to receive an actual output of the rotary steerable drilling system and the estimated output from the system simulator, and, using the processing unit, generate an error compensation signal based on a difference between the actual output and the estimated output;
• an error source detection module comprising a filter, comprising a low pass filter, a band pass filter and a high pass filter,
• wherein the error source detection module is operable to receive the error compensation signal and, using the processing unit, detect one or more sources of error by applying the electronic filter to the error compensation signal,
• wherein the filter passes a signal indicative of an error source,
• wherein the low pass filter is used to identify mathematical modeling errors, the band pass filter is used to identify physical disturbances including stick slip and the high pass filter is used to identify high frequency noise and disturbances;
• wherein the error compensation signal is an input to the mathematical model;
• and
• wherein the rotary steerable drilling system is steerable by adjusting a toolface angle based on the estimated state.

A rotary steerable drilling system with state estimation, comprising:

• a rotary steerable drilling tool configured to receive a control input and exhibit a sensed output and a state;
• a processing unit providing:
• a rotary steerable drilling tool simulator, wherein the rotary steerable drilling tool simulator comprises a mathematical model of the rotary steerable drilling tool, the rotary steerable drilling tool simulator configured to receive the control input and generate an estimated output and an estimated state of the rotary steerable drilling tool in response to the control input and without a sensing device in the rotary steerable drilling tool to directly measure the state;
• and
• a simulator controller configured to receive the sensed output of the drilling tool and the estimated output from the drilling tool simulator, and generate an error compensation signal based on a difference between the sensed output and the estimated output;
• wherein the rotary steerable drilling tool simulator is configured to receive the error compensation signal as an input to the mathematical model and generate the estimated output and the estimated state in response to the control input and the error compensation signal;
• wherein the error compensation signal is configured to drive the difference between the sensed output and the estimated output towards zero and
• wherein the processing unit further comprises a filter, comprising a low pass filter, a band pass filter and a high pass filter,
• wherein the error source detection module is operable to receive the error compensation signal and, using the processing unit, detect one or more sources of error by applying the filter to the error compensation signal,
• wherein the filter passes a signal indicative of an error source,
• wherein the low pass filter is used to identify mathematical modeling errors, the band pass filter is used to identify physical disturbances including stick slip and the high pass filter is used to identify high frequency noise and disturbances;
• and
• wherein the rotary steerable drilling system is steerable by adjusting a toolface angle of the rotary steerable drilling tool based on the estimated state.