Drilling State Determination for Trajectory Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current trajectory control methods during directional drilling are hindered by dynamic conditions such as axial vibration, sensor response delays, and inability to distinguish between drilling states like active drilling and back-reaming, leading to reduced accuracy in wellbore trajectory.
Innovation Solution
A method to determine the drilling state of a downhole tool by establishing threshold values for drilling parameters, comparing actual values measured by sensors, and adjusting the operation of integral controllers based on these states to improve trajectory control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a proportional controller is used for trajectory control, then the control system is simple, but steady-state error increases due to dynamic conditions like axial vibration and sensor response delay
Solution Approach 1:
The patent implements dynamic adaptation of controller parameters based on real-time drilling state detection. The system transitions from static proportional control to dynamic control that adjusts gain values according to detected drilling conditions (bit rotation, weight on bit, drill string movement), thereby maintaining trajectory accuracy across varying operational conditions without requiring complex reconfiguration.
Solution Approach 2:
The patent introduces feedback mechanisms by continuously monitoring drilling parameters (bit rotation speed, weight on bit, drill string position and movement) and using this information to adjust controller behavior. The feedback loop detects drilling state changes and modifies control responses accordingly, compensating for dynamic conditions and reducing steady-state error while maintaining system simplicity.
2Manufacturing precision
If a PI controller with integrator is used to account for dynamic conditions and sensor delay, then trajectory control accuracy improves, but the integrator cannot distinguish between different drilling states (active drilling, back-reaming, circulating on bottom), leading to inhibited control during certain states
Solution Approach 1:
The patent segments the drilling operation into distinct states (active drilling, back-reaming, circulating on bottom) based on detected drilling parameters. By dividing the operational spectrum into discrete states with specific characteristics, the system can apply state-specific control strategies rather than using a single unified control mode, thereby maintaining accuracy across diverse drilling conditions.
Solution Approach 2:
The system dynamically adapts controller behavior based on real-time drilling state detection. When back-reaming or circulating on bottom is detected, the control system adjusts its response characteristics accordingly, allowing the integrator to function effectively only when appropriate (during active drilling) while suppressing or modifying control actions during non-drilling states, thus preventing control inhibition.
3Manufacturing precision
If the integrator is used continuously to account for sensor response delay, then steady-state error is reduced, but control effectiveness is reduced during back-reaming and circulating on bottom operations
Solution Approach 1:
The patent implements periodic evaluation of drilling states and conditional activation of control modes. The system periodically assesses drilling conditions and activates the integrator only during active drilling phases when trajectory control is most critical, while suppressing or modifying control actions during back-reaming and circulating periods, thereby optimizing the balance between accuracy and operational effectiveness.
Solution Approach 2:
The system dynamically changes control parameters (integrator gain, proportional gain) based on detected drilling state. During active drilling, the integrator operates with full gain to eliminate steady-state error. During back-reaming or circulating, the control parameters are modified (reduced or zeroed) to prevent ineffective or harmful control actions, thus adapting the control strategy to match the current operational phase.
Data Source
AI summary
Methods are provided for determining the drilling state of a downhole tool and controlling the trajectory of the downhole tool in a wellbore during a drilling operation. One method may include identifying a drilling parameter indicative of the drilling state of the downhole tool in the wellbore. The method may also include determining the drilling state based on the identified drilling parameter. The identified drilling parameter may be obtained from a sensor communicatively coupled with a processor and disposed in the wellbore. The method may further include adjusting the operation of an integral controller based on the determined drilling state to control the trajectory of the downhole tool in the wellbore during the drilling operation.