Subsea Winch Tension Assembly for Conductor Straightening

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Solution Overview

Problem

Subsea primary conductors often become permanently bent due to excessive bending loads exceeding the yield strength of their material, complicating the alignment and engagement of remedial devices during well maintenance, and existing methods for straightening them are cumbersome and prone to uncontrolled loads.

Innovation Solution

A system comprising an adapter and tension assembly mounted to a subsea anchor, which applies a controlled tensile load to the primary conductor using a flexible tension member to straighten it back to a vertical orientation, with mechanisms to secure and lock the conductor in place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a surface vessel is used to apply lateral loads on the LMRP and BOP to straighten the primary conductor, then the conductor can be pulled back to vertical orientation, but the vessel drift and uncontrolled loads may cause plastic deformation and permanent bending of the conductor

Engineering Contradiction:

Improvevertical orientation of primary conductorVSAvoidstructural integrity of primary conductor

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

A subsea winch system acts as an intermediary between the surface vessel and the primary conductor. The winch is coupled to the LMRP via a wire rope and provides controlled tensile loads to straighten the conductor without the vessel needing to directly pull on it, thereby eliminating uncontrolled loads and vessel drift issues

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the direct mechanical pulling system (vessel to conductor) with a controlled subsea mechanical system (winch to LMRP via wire rope). This substitution allows precise control of the loading process and eliminates the harmful effects of vessel movement and uncontrolled forces

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If the primary conductor is pulled back to vertical orientation using external forces, then alignment for remedial devices is improved, but excessive or uncontrolled loads may exceed the yield strength and cause permanent deformation

Engineering Contradiction:

Improvealignment precision for remedial devicesVSAvoidyield strength of primary conductor material

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The system incorporates monitoring of the tensile loads applied by the subsea winch, allowing real-time feedback control to ensure that forces remain within the yield strength of the conductor material. This prevents plastic deformation while achieving the desired vertical alignment

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent uses a dynamic winch system that can adjust tensile loads in real-time during the straightening process. The winch can apply controlled forces to bend the conductor back to vertical while monitoring and adjusting the load to stay below the yield strength threshold, preventing permanent deformation

Inventive Principle:

Principle #15Dynamics

3Ease of manufacture

If traditional surface vessel methods are used for straightening, then the process can be performed with existing equipment, but the methods are cumbersome and prone to uncontrolled loads

Engineering Contradiction:

Improvesimplicity of straightening processVSAvoidcontrol precision of loading process

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The subsea winch system is self-contained and can operate independently once deployed. The winch, coupled to the LMRP, provides self-controlled tensile loading without requiring continuous surface vessel intervention, making the process simpler and more controllable

Inventive Principle:

Principle #25Self-service

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

Enables precise and controlled straightening of bent subsea conductors without the need for surface vessel intervention, reducing the risk of further damage and simplifying the installation of remedial devices by applying carefully managed loads.

Implementation Method 1

A flexible tension member can be coupled to the primary conductor... The tension assembly is configured to apply a tensile load to the tension member

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS9284806B2Systems and methods for pulling subsea structures

Publication Date: 2016.03.15 BP CORP NORTH AMERICA INC

AI summary

A system for pulling a subsea structure includes an adapter configured to be mounted to an upper end of a subsea pile. In addition, the system includes an interface assembly fixably coupled to the adapter. The interface assembly includes a first channel configured to receive a flexible tension member and a first chuck disposed in the first channel. The tension assembly includes a second channel configured to receive the flexible tension member and a second chuck disposed in the second channel. Each chuck is configured to pivot about a horizontal axis between an unlocked position allowing the flexible tension member to move in a first axial direction and a locked position preventing the tension member from moving in a second axial direction that is opposite the first axial direction.