Subsea Support Isolating Wellhead Loads
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Solution Overview
Problem
Conventional subsea drilling systems face challenges in managing increasing mechanical loads due to larger equipment and deeper water pressures, leading to fatigue damage in wellhead components, as these loads are directly transmitted to the pressure-containing sections, exceeding the operational window and risking catastrophic failure.
Innovation Solution
A subsea support system that decouples external mechanical loads from pressure-containing components by transmitting them to the seabed, using compliant elements and modular structures to absorb and distribute loads, thereby isolating critical well components from stress and allowing them to remain fixed relative to the pressure conductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional subsea drilling systems are used with larger equipment and deeper water operations, then drilling capability and water depth range are improved, but mechanical loads on wellhead components increase leading to fatigue damage and operational window limitations
Solution Approach 1:
A subsea support structure is introduced as an intermediary component between the drill rig and the wellhead system. This support structure absorbs and distributes mechanical loads, preventing direct transmission of stresses to the pressure-containing wellhead components. The intermediary structure includes support legs anchored to the seabed and compliant connectors that accommodate movement while isolating the wellhead from excessive loads.
Solution Approach 2:
The subsea support system divides the load-bearing function into separate segments: the support structure handles mechanical loads from the drill rig, while the wellhead system maintains pressure containment. This segmentation allows each component to be optimized for its specific function without being overloaded by combined demands.
2Device complexity
If mechanical loads are directly transmitted to pressure-containing wellhead components, then structural support is simplified, but fatigue damage occurs and operational window is exceeded
Solution Approach 1:
The subsea support structure serves as a mediator that takes on the role of handling mechanical loads, allowing the wellhead system to focus on pressure containment. This intermediary function extends the operational window by preventing cumulative fatigue damage while maintaining necessary structural support.
3Adaptability or versatility
If larger equipment is used to handle deeper water operations, then water depth range is improved, but mechanical loads increase causing fatigue damage to wellhead components
Solution Approach 1:
The subsea support structure acts as a protective intermediary that shields the wellhead components from harmful mechanical loads generated by larger equipment and deeper water operations. The support structure's legs are anchored to the seabed and equipped with compliant connectors that absorb load variations while maintaining system stability.
Solution Approach 2:
The system converts the potentially harmful effect of increased mechanical loads into a beneficial outcome by using the support structure to absorb and distribute these loads. The compliant connectors transform load variations into controlled movements, protecting the wellhead while enabling deeper water operations.
4Reliability
If compliant support is used to isolate wellhead from loads, then structural integrity is improved, but device complexity increases
Solution Approach 1:
The subsea support structure provides compliant support through intermediary components including support legs with compliant connectors. These connectors allow controlled movement and rotation while maintaining isolation between the drill rig and wellhead, protecting structural integrity through deliberate compliance rather than rigid connection.
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
This solution reduces the risk of damage to pressure elements by absorbing and distributing mechanical loads, enabling the use of smaller pressure conductor casings and extending the operational window for subsea drilling operations, while maintaining the structural integrity of critical well components.
Implementation Method 1
A subsea support for a component which is fixedly connected to a pressure conductor in a seabed, the subsea support being configured to compliantly support the component
Implementation Method 2
substantially all of an external mechanical load which is applied to the subsea support is transmitted by the subsea support to the seabed
Data Source
AI summary
A subsea support system comprises: at least one component (501) which is configured to be fixedly connected to a pressure conductor (101) in a seabed; and a subsea support (601) which is configured to compliantly support the at least one component (501); wherein, when the at least one component (501) is fixedly connected to the pressure conductor (101), substantially all of a mechanical load (T) which is applied to the subsea support (601) is transmitted by the subsea support (601) to the seabed while the at least one component (501) is substantially free of the mechanical load and remains fixed relative to the pressure conductor (101).