Wellhead Stabilization via Suction Substructure Load Distribution
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Solution Overview
Problem
The installation of wellhead elements, particularly blowout preventers, on seabed casings is prone to fatigue due to sideways forces from riser drift, leading to deformation and potential failure, as existing solutions do not adequately address the bending strains caused by the weight and displacement of these heavy components.
Innovation Solution
A stabilization method and device using a suction substructure with multiple supporting elements arranged between the blowout preventer and the suction substructure, allowing for adjustable and remotely operable support to distribute loads and reduce bending moments, enabling the blowout preventer to be positioned and secured independently of the wellhead casing's central axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the blowout preventer is positioned away from the wellhead casing central axis to facilitate installation and operation, then the ease of operation is improved, but the bending strain on the wellhead casing increases leading to fatigue
Solution Approach 1:
A support structure is introduced as an intermediary element between the blowout preventer and the wellhead casing. This support structure carries the weight of the blowout preventer and transfers it to the seabed, preventing the weight and bending moments from being transmitted to the wellhead casing, thus allowing the blowout preventer to be positioned away from the central axis without compromising casing strength
Solution Approach 2:
The support structure is divided into multiple supporting elements arranged around the wellhead casing. These elements distribute the load to the seabed at multiple points, reducing the bending strain on the wellhead casing while providing stable support for the blowout preventer positioned away from the central axis
2Reliability
If the blowout preventer weight is increased to ensure adequate sealing and control capability, then the reliability is improved, but the bending strain on the wellhead casing increases due to displaced center of gravity
Solution Approach 1:
The support structure acts as a mediator that carries the increased weight of the blowout preventer directly to the seabed through multiple supporting elements, preventing this weight from creating bending moments on the wellhead casing. This allows the use of heavier, more reliable blowout preventers without compromising casing integrity
Solution Approach 2:
The support structure provides a counterbalancing effect by distributing the blowout preventer weight to the seabed, creating a stable support system that offsets the gravitational load and prevents it from translating into bending strain on the wellhead casing
3Stability of the object's composition
If multiple supporting elements are added to support the blowout preventer away from the central axis, then the stability is improved, but the device complexity increases
Solution Approach 1:
The support structure serves multiple functions: it supports the blowout preventer weight, provides lateral stability, enables positioning away from the central axis, and distributes loads to the seabed. By combining these functions into a single integrated structure, the overall device complexity is managed while achieving high stability
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 effectively reduces the risk of wellhead casing fatigue by distributing horizontal loads and allowing for flexible positioning and securement of the blowout preventer, thereby enhancing the stability and longevity of the wellhead installation.
Implementation Method 1
a suction substructure formed by a polygonal or cylindrical substructure element which in an upper end portion is essentially closed by an end cover arranged to be able to take up a vertical load and to transfer a horizontally directed load component
Data Source
AI summary
A stabilization device is for a wellhead wherein an upper portion of a wellhead casing extends up above a seabed, the upper wellhead casing portion being sideways supported in a suction substructure. A blowout preventer extending up from the upper portion of the wellhead casing is provided with multiple supporting elements abutting supportingly an edge portion of an end cover on the suction substructure. A method is for stabilizing a wellhead wherein an upper portion of a wellhead casing extends up above a seabed and is sideways supported in a suction substructure surrounding the wellhead casing portion and extends downward in an uncompacted material.