Rotary Bearing Locking for RCD Seal Integrity Under Pressure
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Solution Overview
Problem
Conventional rotating control devices (RCDs) face issues with seal failure due to poor structural integrity, loose clamping, and manual installation challenges, particularly during high-pressure wellbore operations, leading to inefficiencies and safety concerns.
Innovation Solution
A rotating control device with a latched interlocking interface between the bearing assembly and the bowl, utilizing an electrically powered rotary guide and alignment profile for secure coupling, allowing remote operation and reducing the need for hydraulic systems, and featuring a retention assembly to maintain the sealing element's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional flexible seals are used in RCDs, then the sealing element can conform to irregular tubular surfaces, but the seal has poor structural integrity and rolls up inwardly during tripping out under high pressure
Solution Approach 1:
The sealing element uses a flexible membrane structure that can conform to irregular tubular surfaces while maintaining integrity. The membrane is designed with appropriate thickness and material properties to resist rolling up inwardly during high-pressure tripping operations, combining flexibility for adaptation with sufficient structural strength.
2Reliability
If axial or radial cap screws are used to secure the sealing element, then the sealing element is attached to the bearing assembly body, but the screws can become damaged or damage the bowl during installation
Solution Approach 1:
The design eliminates cap screws and safety wires from the sealing element attachment system. Instead, the sealing element is secured through integrated mechanical features such as retention ribs, snap-fit mechanisms, or interference fits that attach the seal directly to the bearing assembly body without requiring separate fastening components, thereby removing the source of installation damage.
3Force
If bolted clamps are used to retain the bearing assembly, then clamping force can be provided, but installation and removal requires personnel on site and bolts may loosen due to vibration
Solution Approach 1:
The bearing assembly retention system uses self-latching mechanisms or friction-fit interfaces that automatically secure the bearing assembly in place without requiring external bolting or clamping. The design incorporates features such as tapered surfaces, elastic retention rings, or interlocking geometries that provide sufficient clamping force through the assembly process itself, eliminating the need for separate fastening operations and reducing vulnerability to vibration loosening.
4Extent of automation
If hydraulic clamps are used to retain the bearing assembly, then remote operation is possible, but hydraulic power units and long pressurized hoses are required and any power outage or leakage can cause loosening
Solution Approach 1:
The design eliminates hydraulic clamps, power units, and pressurized hoses from the bearing assembly retention system. Instead, passive mechanical retention features such as interference fits, retention ribs, or spring-loaded latches are used that require no external power source or fluid supply, thereby removing the complexity of hydraulic systems while maintaining secure retention through purely mechanical means.
5Reliability
If safety wires are used to tie together the screws, then loosening of screws is prevented, but the installation is time consuming and quality varies with technician skill level
Solution Approach 1:
The design removes screws and safety wires from the sealing element attachment system. The sealing element is secured through integrated mechanical retention features such as molded-in retention ribs, snap-fit edges, or interference fit geometries that are built into the seal and bearing assembly structure, eliminating the need for separate fastening components and the time-consuming process of installing and wire-tying screws.
Data Source
AI summary
A rotating control device wherein the bearing assembly can be secured to the bowl by rotationally coupling the bearing assembly with the bowl. When the bearing assembly is rotated in a first direction about a longitudinal axis relative to the bowl, an interlocking interface is formed between the inner surface of the bowl and the outer surface of the bearing assembly. The interlocking interface can be released by rotating the bearing assembly in a second direction relative to the bowl. The bowl comprises a rotary guide for engaging and rotating the bearing assembly. The rotary guide and the bearing assembly have an alignment profile for facilitating alignment of the bearing assembly with the bowl. The bearing assembly has a sealing element with axially extending fingers to provide internal structural support for the seal.