Elastically Deformable Lobes for Drilling Motor Sealing
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Solution Overview
Problem
Conventional metal-metal mud motors suffer from inefficiency due to lack of sealing between the rotor and stator, leading to reduced performance in drilling operations, especially in deviated and horizontal boreholes.
Innovation Solution
The implementation of a metallic stator and rotor with an interference seal provided by elastically deformable lobes, which create a tight seal between the rotor and stator, enhancing the sealing efficiency and operational performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a clearance is designed between the rotor and stator to allow assembly of the mud motor, then ease of manufacture is improved, but efficiency deteriorates as drilling fluid flows across the clearance
Solution Approach 1:
The patent applies parameter changes by transitioning from a rigid metal-metal clearance design to an elastic metal-metal interference seal design. The elastic rotor lobes are designed with specific material properties (modulus of elasticity between 100,000 and 500,000 psi) and geometric parameters (radial thickness, length, and interference fit dimensions) that allow them to deform and seal against the stator, eliminating the clearance while maintaining assembly capability through controlled elastic deformation.
Solution Approach 2:
The patent employs composite material principles by combining metal rotor lobes with elastic properties. The rotor lobes are made of elastic metal material that exhibits both structural integrity and elastic deformation characteristics, creating a composite behavior between rigid metal and elastic sealing elements. This allows the rotor to maintain its shape while deforming elastically to seal the clearance, reducing fluid flow loss across the rotor-stator interface.
2Loss of energy
If an interference seal is implemented between the rotor and stator, then efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies dynamics by designing the rotor lobes to be elastic rather than rigid, allowing them to dynamically adapt to the stator surface during rotation. The elastic lobes deform under pressure to create and maintain the interference seal, then return to their original shape, enabling continuous sealing action throughout the rotation cycle. This dynamic sealing mechanism achieves efficient sealing without complex additional sealing components.
Solution Approach 2:
The elastic rotor lobes perform self-service by automatically adjusting their deformation to maintain the interference seal. The material elasticity allows the lobes to self-regulate the contact pressure and sealing interface position based on operating conditions, eliminating the need for external adjustment mechanisms or complex control systems to maintain sealing effectiveness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The metal-metal mud motor with an interference seal achieves improved efficiency and operational reliability, capable of handling higher downhole temperatures and maintaining performance in drilling fluids, overcoming the limitations of conventional metal-metal designs.
Implementation Method 1
the rotor includes a lobe member that provides an interference seal between the stator and the rotor
Data Source
AI summary
In an aspect, a drilling motor is provided that in one embodiment includes a stator and a rotor configured to be disposed in the stator, wherein the rotor includes a lobe member having an elastically deformable surface configured to provide an interference seal between the stator and the rotor.