CPC E21B 44/08 (2013.01) [E21B 1/38 (2020.05); E21B 49/003 (2013.01); E21B 2200/22 (2020.05)] | 17 Claims |
1. A method for autonomously controlling a drilling system comprising:
applying a predetermined force setpoint to a first controller; applying a predetermined rotary speed to a second controller;
applying a first controller output and a second controller output to a drilling process module; measuring a plurality of outcome parameters of the drilling process module;
receiving drilling process inputs from downhole sensor data and processing and process outcome parameters;
estimating a plurality of rock parameters associated with a rock type;
comparing the estimated rock parameters with a database of rock profiles; determining whether a change in the outcome parameters have occurred which indicate that a change in the drilled material has occurred;
searching the database rock profiles for optimal operating conditions in response to determining that a change in the material being drilled is indicated;
generating an updated set of drilling parameters corresponding to the optimal operating conditions rock parameters in response to the comparing of database rock profiles by executing machine-executable instructions stored in a computer;
transmitting the updated set of drilling parameters comprising the force setpoint and rotary speed setpoint;
adjusting the drilling parameters by subtracting measured drilling parameters from the updated set of drilling parameters; and
generating adjusted drilling parameter setpoints for predetermined force and predetermined angular velocity; and
determining whether the adjusted drilling parameter setpoints are approaching stall conditions;
wherein the step of determining stall conditions further comprises:
monitoring the torque;
determining that the torque exceeds a predetermined torque;
reducing the target weight on bit by an amount determined by a barrier function configured to respond more rapidly to material changes.
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