Subsea Centralization Tool Radial Seal for Angular Deviation
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Solution Overview
Problem
Existing subsea drilling technologies face challenges in achieving a fluid-tight seal against the drill stem and surrounding seawater, particularly during top hole drilling, while also centralizing the drill stem effectively to manage angular deviations.
Innovation Solution
A centralization and running tool with a rotary packing housing and seals that move radially to accommodate angular deviations, housed in an outer housing with additional seals and a support seal, allowing for rotation and axial alignment with the drill stem, providing a fluid-tight seal against both the drill stem and seawater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed seal structure is used against the drill stem, then sealing is achieved, but the drill stem cannot accommodate angular deviations
Solution Approach 1:
The patent applies the dynamics principle by making the seal structure movable rather than fixed. The seal assembly is designed to move radially in response to angular deviations of the drill stem, allowing the sealing surface to track and maintain contact with the drill stem even when it deviates from the vertical axis. This dynamic adjustment capability resolves the contradiction between maintaining a reliable seal and accommodating angular movements.
Solution Approach 2:
The patent employs parameter changes by allowing the seal assembly to change its radial position dynamically. When the drill stem experiences angular deviations, the seal assembly moves radially to adjust its position, thereby maintaining effective sealing contact. This parameter adjustment enables the system to adapt to varying drill stem orientations while preserving sealing integrity.
2Adaptability or versatility
If a radial movement mechanism is added to accommodate angular deviations, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent applies the merging principle by combining the sealing function with the angular deviation accommodation function into a single integrated seal assembly. Rather than adding a separate radial movement mechanism to an existing fixed seal, the design merges these functions so that the seal structure itself is capable of radial movement. This integration reduces overall device complexity while maintaining adaptability.
Solution Approach 2:
The seal assembly is designed as a multi-functional component that simultaneously provides sealing and accommodates angular deviations through radial movement. This universal design eliminates the need for separate mechanisms for each function, thereby reducing device complexity while achieving both sealing reliability and angular deviation accommodation.
3Reliability
If multiple seals are used to ensure fluid-tight sealing, then sealing reliability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies segmentation by dividing the sealing system into multiple discrete seal elements arranged in series around the drill stem. Each seal element contributes to the overall fluid-tight sealing, and the segmented structure allows each seal to be optimized independently while working together as a system. This segmentation approach enhances sealing reliability without requiring an overly complex integrated structure.
Solution Approach 2:
The patent employs nesting by arranging multiple seal elements within a compact, hierarchical structure. The seals are nested within the seal assembly housing, with each seal positioned in a specific radial and axial location. This nested arrangement achieves fluid-tight sealing through multiple barriers while maintaining a compact and manageable device structure, reducing overall complexity.
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 effectively centralizes and seals the drill stem, preventing fluid leakage and accommodating angular movements, ensuring reliable drilling operations in subsea environments.
Implementation Method 1
the packing housing, in accordance with the movement of the drill stem, is arranged for radial movement to take up angular deviations of the drill stem
Implementation Method 2
said packing housing with seals is arranged to rotate in the outer housing together with the drill stem
Implementation Method 3
The outer housing preferably comprises a support seal, preferably incorporating a lip-seal, for the packing housing, arranged to function as a scraper and seal
Data Source
AI summary
The invention relates to a centralization and running tool (CTR) in a subsea installation in connection with offshore related oil and gas exploration, where the subsea installation (SCM) is arranged to be placed on the ocean bottom or a drilling template and comprises a pipe-formed body (10), at least partially open at the top and extended, arranged to receive and carry through a drill stem (12) from a drilling rig or a drilling vessel. The centralization and running tool (20) is arranged to surround the drill stem (12) and to be placed in the pipe-formed body (10), and the centralization and running tool (20) comprises, together with the drill stem (12), a rotary packing housing (22) with a number of seals (24,26) that lie against the drill stem (12), and the packing housing (22), in accordance with the movements of the drill stem (12), is arranged for radial movement to take up angular deviations of the drill stem (12). The invention also relates to a method to provide a fluid-tight seal against a drill stem (12) and against the surroundings in a subsea installation.