Mud Motor Vibration Modeling via Section Segmentation
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Solution Overview
Problem
Current drilling technologies lack effective modeling of vibration effects introduced by mud motors, which are crucial for enhancing drilling operations but are complex and costly to simulate accurately, especially when considering transient aspects and higher frequency vibrations.
Innovation Solution
A method and apparatus that model vibration effects by computing separate vibration effects for each section of the mud motor, interacting sections, and controlling drilling aspects based on these modeled effects, using sensors and computational models to refine drilling plans and operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If highly complex multi-physics numerical methods such as finite elements with fluid-structure interaction are used to obtain accurate prediction of mud motor behavior, then measurement precision is improved, but device complexity and computational cost increase prohibitively
Solution Approach 1:
The mud motor is divided into multiple discrete sections (stator, rotor, bearings, seals) with each section modeled separately using simplified assumptions. This segmentation allows the complex fluid-structure interaction to be broken down into manageable components that can be computed efficiently while maintaining adequate prediction accuracy for drilling applications.
Solution Approach 2:
The patent employs computationally inexpensive models that can be rapidly executed for thousands of different motor configurations during time-transient simulations. Rather than using expensive finite element models for each configuration, simplified models are used that provide sufficient accuracy for the specific application of predicting vibration effects in drilling operations.
2Device complexity
If simplified models are used to reduce computational cost, then device complexity is reduced, but measurement precision and ability to capture transient aspects deteriorate
Solution Approach 1:
Different levels of modeling complexity are applied to different sections of the mud motor based on their specific characteristics and contribution to vibration. Critical sections where transient effects are most significant are modeled with higher fidelity, while less critical sections use simpler models, optimizing the balance between computational efficiency and prediction accuracy.
Solution Approach 2:
The model incorporates key parameters such as mud pressure, mud flow rate, torque, and relative motor RPM that directly influence vibration behavior. By focusing computational resources on accurately modeling these critical parameters rather than all physical aspects, the system achieves adequate prediction accuracy with reduced complexity.
3Measurement precision
If comprehensive modeling of all vibration components is attempted, then measurement precision is improved, but loss of time and computational resources increase
Solution Approach 1:
The model pre-identifies and focuses computational effort on the primary vibration mechanisms specific to mud motors (lateral vibrations from rotor whirling, coupled dynamics of pressure-flow-torque-RPM) rather than attempting to model all possible vibration sources. This preliminary identification of critical mechanisms reduces computation time while maintaining accuracy for mud motor-specific vibrations.
Solution Approach 2:
The model captures the most significant vibration effects that dominate mud motor behavior (lateral vibrations, coupled dynamics) without attempting to model every minor vibration component. This partial action approach focuses computational resources on the critical few mechanisms that have the greatest impact on drilling operations.
Data Source
AI summary
Torsional, axial and lateral vibrations introduced when a mud motor is used with a drilling tool to drill a borehole are calculated using a model. The model includes different computational modules for each of three distinct motor sections: power, transmission and bearing. The resulting calculated vibration effects are used to enhance the drilling tool and drilling operation.