Drill String Optimization for Stick-Slip Vibration Reduction
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Solution Overview
Problem
Current drill string designs are not optimized for minimizing stick-slip vibrations during drilling operations, leading to inefficiencies, equipment damage, and increased costs due to the need for frequent adjustments and replacements.
Innovation Solution
A method for predicting and optimizing drill string configurations and parameters based on initial drilling data, using Torsional Severity Estimates (TSE) and theoretical specific surface torque swings to select modified drill strings and parameters that reduce stick-slip vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed cutter bit is used to drill at faster rates, then productivity increases, but stick-slip vibrations increase causing equipment damage
Solution Approach 1:
The patent applies parameter changes by modifying drill string physical properties (mass distribution, stiffness, damping characteristics) to alter the system's dynamic response. Specifically, it changes the mass ratio between drill collars and drill pipe, adjusts stiffness parameters of the drill string components, and modifies damping characteristics to shift the stick-slip vibration threshold and reduce vibration severity at high drilling rates.
Solution Approach 2:
The patent employs dynamics by transitioning from static drill string design to dynamic optimization. It considers the time-varying nature of drilling parameters (weight on bit, rotational speed, rate of penetration) and designs the drill string to maintain optimal dynamic characteristics throughout the drilling process. The solution accounts for the coupled axial-torsional vibrations and their interaction with the drilling system's boundary conditions.
2Device complexity
If drill string assembly is designed without vibration optimization, then device complexity is reduced, but equipment failure rate increases
Solution Approach 1:
The patent applies preliminary action by performing comprehensive vibration analysis and drill string optimization during the design phase, before the actual drilling operation begins. It calculates optimal mass ratios, stiffness parameters, and damping characteristics in advance, allowing the drill string to be pre-configured to resist stick-slip vibrations under expected drilling conditions, thereby preventing equipment failure without adding operational complexity.
3Ease of manufacture
If traditional drill string design is used, then manufacturing cost is reduced, but non-productive time increases due to frequent trips and replacements
Solution Approach 1:
The patent modifies key design parameters including increasing the mass ratio of drill collars to drill pipe (optimizing inertial properties), adjusting the stiffness distribution along the drill string, and incorporating damping elements. These parameter changes enhance the drill string's resistance to stick-slip vibrations, reducing equipment fatigue and failure, thereby extending drill string life and reducing non-productive time for trips and replacements.
Data Source
AI summary
The present disclosure relates generally to the field of drilling operations. More particularly, the present disclosure relates to methods for drilling wells utilizing drilling equipment, more particularly drill string assemblies, and predicting modified drilling operation conditions based on proposed changes to the drill string configuration and/or the drilling parameters. Included are methods for drilling wells utilizing a method for the selection of modified drill string assemblies and/or modified drilling parameters.