Subsea Actuator Control with a Flexible Drive Shaft

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Solution Overview

Problem

Existing subsea control systems for wellheads are inefficient and require complex hydraulic controls, which can be cumbersome and prone to failure, especially in deep-sea environments.

Innovation Solution

A subsea control unit that utilizes a single electrically-powered drive source to control multiple actuators via a flexible drive shaft and mechanical transmission, eliminating the need for hydraulic systems and allowing for flexible angular transitions and simultaneous or sequential actuation of multiple actuators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic control systems are used for subsea actuators, then actuation capability is achieved, but system complexity and susceptibility to failure increase

Engineering Contradiction:

Improvesystem reliabilityVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces hydraulic control systems with an electrically-powered drive source that uses a flexible drive shaft and mechanical transmission to actuate subsea valves. This substitution eliminates hydraulic fluid, pumps, and associated control infrastructure, thereby reducing system complexity and potential failure points while maintaining actuation capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention extracts and removes the hydraulic system components from the subsea control architecture. By eliminating hydraulic fluid reservoirs, pumps, valves, and associated piping, the system achieves lower complexity and improved reliability while the electric motor with flexible drive shaft provides the necessary mechanical actuation force.

Inventive Principle:

Principle #2Taking out (Extraction)

2Adaptability or versatility

If multiple separate drive sources are used for multiple actuators, then each actuator can be controlled independently, but system complexity and space requirements increase

Engineering Contradiction:

Improveactuator control flexibilityVSAvoiddrive system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple actuator control functions into a single electrically-powered drive source. The flexible drive shaft distributes mechanical power to multiple actuators, allowing independent control of each actuator while using one consolidated drive unit. This reduces the number of separate motor assemblies and simplifies the overall drive system architecture.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single electric motor serves multiple functions by controlling multiple subsea actuators through the flexible drive shaft mechanism. This multi-functional drive source can selectively engage different actuators as needed, providing versatile control capability without requiring separate dedicated motors for each actuator.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Power

If rigid mechanical linkages are used for drive transmission, then mechanical power is transmitted efficiently, but angular transitions and flexibility are limited

Engineering Contradiction:

Improvemechanical power transmissionVSAvoidangular transition capability

Core Design Contradiction:

PowerVSAdaptability or versatility

Solution Approach 1:

The patent employs a flexible drive shaft instead of rigid mechanical linkages for power transmission. This flexible shaft can bend and articulate through angular transitions while still efficiently transmitting mechanical torque from the electric motor to the actuators. The flexibility allows the drive system to adapt to varying spatial configurations and angular positions.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible drive shaft introduces dynamic adaptability to the mechanical power transmission system. Rather than fixed rigid connections, the flexible shaft can dynamically adjust its configuration to accommodate angular movements and position changes, enabling the system to operate in varied spatial arrangements while maintaining efficient power transfer.

Inventive Principle:

Principle #15Dynamics

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 efficient, reliable, and flexible control of subsea actuators, reducing complexity and enhancing reliability in deep-sea operations by using a single power source and mechanical transmission, facilitating simultaneous or sequential actuation of multiple actuators.

Implementation Method 1

A subsea control unit that utilizes a single electrically-powered drive source to control multiple actuators via a flexible drive shaft and mechanical transmission

Methodology Applied

Scientific EffectFlexible mechanical transmission:

Implementation Method 2

A subsea control unit that utilizes a single electrically-powered drive source

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP4172458B1Subsea control, actuator and associated methods

Publication Date: 2025.09.10 ONESUBSEA AS

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AI summary

Method and apparatus for controlling a subsea actuator, particularly controlling at least two subsea actuators associated with a wellhead. The method comprises controlling the subsea actuators with a single subsea control unit. A mechanical output is provided and mechanical drive is transferred to the actuator/s, such as via a mechanical connector. The actuator can control a valve, such as to selectively open or close access to a bore below a Xmas tree associated with a hydrocarbon wellbore.