Stick-Slip Mitigation via Stability Model Parameter Adjustment

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing drilling systems face challenges in effectively mitigating higher-order stick-slip torsional oscillations, as current surface-based damping mechanisms often focus on low-order models, neglecting the interplay between control parameters and higher-order dynamics, leading to drill string fatigue and reduced performance.

Innovation Solution

A method and system that utilize a stability model to adjust top drive speed controller parameters, considering the interplay between proportional and integral components, to mitigate stick-slip vibrations across multiple modes of torsional oscillations, ensuring consistent and effective damping without adversely affecting the drilling system's dynamics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If surface-based damping mechanisms are used with low-order models to mitigate stick-slip vibration, then first-order torsional oscillations are reduced, but higher-order torsional oscillations are not effectively mitigated and can become highly detrimental to the drill string and BHA

Engineering Contradiction:

Improvemitigation of first-order stick-slip vibrationVSAvoidhigher-order torsional oscillations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the control parameters of the speed controller based on a stability model that accounts for higher-order dynamics. The processor dynamically adjusts proportional and integral controller parameters to mitigate both first-order and higher-order torsional oscillations, resolving the contradiction by expanding the model's parameter scope rather than adding physical components.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system continuously monitors drill string operation and uses feedback from the stability model to adjust speed controller parameters in real-time. This closed-loop feedback mechanism allows the system to respond to both first-order and higher-order oscillations dynamically, preventing higher-order oscillations from becoming detrimental while maintaining effectiveness against first-order stick-slip.

Inventive Principle:

Principle #23Feedback

2Speed

If control parameters are changed based on reduced-order models when stick-slip is observed, then immediate response to first-order oscillations is achieved, but the model does not capture all deformation mechanisms and higher-order oscillations occur

Engineering Contradiction:

Improveresponse speed to stick-slip detectionVSAvoidcompleteness of deformation mechanism capture

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The stability model is pre-computed to include higher-order mode shapes and deformation mechanisms before drilling operations begin. This preliminary preparation allows the system to immediately access comprehensive deformation information when stick-slip is detected, achieving both fast response and complete mechanism capture without real-time computational delays.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The reduced-order model is enhanced by incorporating additional parameters representing higher-order mode shapes and deformation mechanisms. This parameter expansion allows the model to capture all relevant deformation mechanisms while maintaining the computational efficiency needed for real-time control parameter adjustment.

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If top drive control uses PI/PID controllers to minimize reflection coefficient around the first natural frequency, then first-order oscillations are dampened, but higher-order oscillations induced by the top drive are not addressed and cause detrimental effects

Engineering Contradiction:

Improvedamping of first-order oscillationsVSAvoidhigher-order oscillations from top drive

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The stability model and control parameter adjustment mechanism are designed to handle multiple oscillation modes simultaneously. The same control framework that dampens first-order oscillations also addresses higher-order oscillations, making the system multi-functional without requiring separate control systems for each oscillation mode.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses feedback from the stability model to adjust control parameters in a way that addresses both first-order and higher-order oscillations. The feedback mechanism monitors for signs of higher-order oscillations and automatically adjusts parameters to mitigate them, preventing the top drive from inducing detrimental higher-mode vibrations while maintaining effective first-order damping.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11156075B2Advisory system for stick-slip mitigation in drilling systems

Publication Date: 2021.10.26 HALLIBURTON ENERGY SERVICES INC

AI summary

The disclosure addresses mitigating stick-slip in drilling systems. In one example, a method of operating a drill string is disclosed for stick-slip mitigation. The method can include: 1) monitoring operation of a drill string, wherein the drill string is rotated via a top drive that is controlled by a speed controller, and (2) changing the value of at least one speed controller parameter of the speed controller in response to torsional oscillations of the drill string during the operation, wherein the value is based on a stability model for the drill string. A stick-slip mitigation advisor for drilling systems is also disclosed herein.