Surface Casing Head with Retractable Flange for Single-Trip Installation
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Solution Overview
Problem
Conventional surface casing heads are too large to pass through conventional rotary tables and diverters, requiring complex and costly installation methods that involve multiple trips and pose safety risks due to the need for significant manual handling, especially when the casing head is pressurized.
Innovation Solution
The surface casing head design includes an outer tubular member with an annular recess and a snap ring that can be moved between extended and retracted positions, allowing axial movement relative to an inner tubular member, and a segmented landing ring that can be actuated to form a shoulder, enabling the casing head to be run-in through rotary tables and diverters with reduced manual handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the surface casing head is designed with a large flange for BOP coupling, then the BOP coupling capability is improved, but the ability to pass through rotary tables and diverters deteriorates
Solution Approach 1:
The patent applies the dynamics principle by making the flange movable rather than fixed. The flange can be retracted into the casing head body during installation to reduce outer diameter, allowing passage through rotary tables and diverters. After installation, the flange is extended to provide the necessary BOP coupling capability. This dynamic transformation resolves the contradiction between needing a large flange for BOP coupling and needing a small outer diameter for installation.
2Adaptability or versatility
If the conventional installation method is used with large flange, then the BOP can be coupled, but the installation complexity and time increase
Solution Approach 1:
The dynamic flange design allows the casing head to be installed in a single trip through rotary tables and diverters by retracting the flange during installation. After installation, the flange is extended to enable BOP coupling. This eliminates the need for multiple trips and complex manual handling operations, significantly reducing installation time while maintaining BOP coupling capability.
3Ease of operation
If manual handling is performed on pressurized casing head, then the components can be manipulated, but the safety risk increases
Solution Approach 1:
The patent replaces manual mechanical handling with hydraulic actuation. The flange extension and retraction, as well as the lock sleeve operation, are performed using hydraulic cylinders that can operate safely on pressurized casing heads. This substitution eliminates the safety risks associated with manual handling of pressurized components while maintaining the necessary component manipulability for proper installation and engagement.
Data Source
AI summary
An outer casing string, including a surface casing head, and associated installation method. In some embodiments, the surface casing head includes an outer tubular member insertable through a diverter of an installed conductor system, an inner tubular member at least partially disposed within and moveable relative to the outer tubular member, and a sleeve ring rotatably coupled to the inner tubular. The outer tubular member has an annular recess. The sleeve ring includes a snap ring that is displaceable between an extended position and a retracted position. In the extended position, at least a portion of the snap ring is received within the annular recess, and the outer tubular member is axially immovable relative to the inner tubular member. In the retracted position, no portion of the snap ring is received within the annular recess, and the outer tubular member is axially moveable relative to the inner tubular member.