Hydrodynamic Journal Bearing Flow Control Bushing for Rotating Control Devices
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Solution Overview
Problem
Rotating control devices for wellbore pressure management face challenges in withstanding high pressures and rotational speeds, leading to component wear and frequent maintenance needs during drilling operations.
Innovation Solution
A rotating control device design featuring a hydrodynamic journal bearing between the inner housing sleeve and flow bushing, utilizing a viscous lubricant and bushing springs to create a hydrodynamic journal bearing, which reduces wear and pressure fluctuations, and includes an annular sealing assembly with elastomeric elements for effective sealing engagement with the tubular.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bearings are used in rotating control devices, then the device can operate under high pressure and rotational speed, but component wear increases and maintenance frequency increases
Solution Approach 1:
The patent applies hydrodynamic lubrication principles by introducing a lubricant into the bearing assembly. The lubricant creates a fluid film between the bearing surfaces, separating the inner housing and outer housing components. This hydraulic separation reduces direct metal-to-metal contact, minimizing wear and enabling continuous operation under high pressure and rotational speed without frequent maintenance interruptions.
2Reliability
If high pressure is applied to maintain wellbore pressure, then sealing effectiveness improves, but component wear and damage increase
Solution Approach 1:
The lubricant acts as an intermediary substance between the high-pressure environment and the bearing components. It transmits the hydraulic pressure needed for sealing while simultaneously protecting the mechanical components from direct exposure to extreme pressures that would cause wear and damage. The lubricant film distributes and absorbs pressure loads, preserving component integrity.
3Productivity
If rotational speed is increased to improve drilling efficiency, then productivity increases, but bearing wear and component damage increase
Solution Approach 1:
The hydrodynamic lubrication system generates a pressure-bearing fluid film through the relative rotational motion itself. As the inner housing rotates at high speed, the lubricant is dragged into the converging gap between bearing surfaces, creating hydrodynamic pressure that supports the load. This allows high rotational speeds to be maintained for improved drilling efficiency while the lubricant film prevents wear and extends component lifespan.
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 solution enhances the durability and performance of rotating control devices by minimizing wear and pressure fluctuations, allowing for continuous operation under high wellbore pressures and rotational speeds without frequent maintenance.
Implementation Method 1
A rotating control device design featuring a hydrodynamic journal bearing between the inner housing sleeve and flow bushing, utilizing a viscous lubricant to create a hydrodynamic journal bearing, which reduces wear and pressure fluctuations
Data Source
Figure 1
Figure 2~3
AI summary
A rotating control device (10) comprises an outer housing (12) having a bore (32) for receiving a tubular member. An inner housing (38) and a piston assembly (56) are rotatably disposed within the outer housing (12). An annular sealing assembly (46) is disposed between the piston assembly (56) and the inner housing (38) so that axial movement of the piston assembly (56) moves the annular sealing assembly (46) into sealing engagement with the inner housing (38) and the tubular member. A plurality of bearings (40, 76, 84) is disposed between the inner housing (38) and the outer housing (12). At least one of the plurality of bearings is a hydrodynamic journal bearing.