Pressure Joint Telescopic Assembly High-Pressure Seal
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Solution Overview
Problem
Conventional marine slip joints used in drilling operations are limited by low pressure capabilities, making them unsuitable for high-pressure workover operations, and require complex and costly dynamic sealing systems, which increase complexity and cost, and pose safety hazards during human intervention.
Innovation Solution
A pressure joint apparatus comprising a low-pressure slip joint with a telescopic assembly fitted with a non-dynamic high-pressure seal, where the telescopic assembly is housed within the slip joint in its non-extended configuration, allowing normal operation without dynamic sealing, and can be extended for high-pressure operations, eliminating the need for additional dynamic seals and reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dynamic seal is provided in the telescopic connector to accommodate relative motion, then motion compensation is achieved, but the cost and complexity of the system significantly increase
Solution Approach 1:
The patent extracts the sealing function from the telescopic connector itself and relocates it to the rig floor level. The rig floor is made pressure-retaining instead of the connector, so the dynamic seal is eliminated from the moving telescopic joints. This resolves the contradiction by removing the complex dynamic sealing requirement while preserving motion compensation through the telescopic mechanism.
Solution Approach 2:
The patent introduces an intermediary pressure-retaining barrier at the rig floor level that mediates between the pressurized wellbore environment and the atmospheric rig environment. This intermediary barrier allows the telescopic connector to move freely without requiring dynamic seals, as the pressure containment function is performed by the static rig floor structure instead.
2Stress or pressure
If higher pressure telescopic connectors are provided with dynamic seals, then workover pressure capability is achieved, but the cost and manufacturing difficulty increase significantly
Solution Approach 1:
The patent extracts the high-pressure containment function from the telescopic connector and assigns it to the rig floor and wellhead assembly. This allows the telescopic connector to be manufactured without complex high-pressure sealing surfaces, as the pressure containment is performed by separately manufactured pressure-retaining components at static locations.
Solution Approach 2:
The patent applies pressure-retaining properties locally at specific locations (rig floor and wellhead) rather than requiring the entire telescopic connector to be pressure-retaining. This allows different parts of the system to have different manufacturing requirements, with only the static pressure-containing components needing high manufacturing precision.
3Productivity
If conventional low pressure slip joints are used, then drilling operations are supported, but they cannot withstand high pressures during workover operations
Solution Approach 1:
The patent creates a universal pressure joint system that can handle both low-pressure drilling and high-pressure workover operations. The system uses a telescopic connector for motion compensation during drilling, and can be configured with pressure-retaining modifications (such as a pressure-retaining rig floor or wellhead assembly) to handle high-pressure workover operations, eliminating the need for separate systems.
Solution Approach 2:
The patent makes the pressure containment configuration dynamic rather than fixed. The system can transition between a non-pressure-retaining configuration for drilling operations and a pressure-retaining configuration for workover operations, allowing the same physical infrastructure to adapt to different operational requirements and pressure levels.
Data Source
AI summary
A pressure joint is provided for use with a floating installation (1) that is connected to a stiff riser (3, 12). A low pressure slip joint (5) connects the installation (1) to the stiff riser (3, 12). A telescopic assembly (13, 14) fitted with a high pressure seal (15) is arranged to be fitted within the low pressure slip joint (5) when in a non-extended configuration, such that normal operation of the low pressure slip joint (5) is not impeded.