Fail-Safe Valve Hydraulics for Compact Subsea Well Control

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Solution Overview

Problem

Conventional modular safety valves in subsea oilfield operations face challenges in providing sufficient actuation force for closure and cutting of interventional access lines while maintaining a low profile, which can lead to hydrocarbon leaks and safety hazards, and require additional space for actuators to reopen the valve for well-killing operations.

Innovation Solution

A fail-safe valve arrangement utilizing dual accumulators for actuating the valve to open and close positions, with a monolithic piston that can cut through obstructions, and a dedicated hydraulic line for reopening, allowing for compact and cost-effective design without the need for large spring-driven actuators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a conventional spring-driven mechanical actuator is used to provide sufficient closing force, then the valve can reliably close and cut through obstructions, but the overall footprint and size of the valve assembly increases

Engineering Contradiction:
Improveclosing forceVSAvoidvalve footprint
Core Design Contradiction:
ForceVSArea of stationary object

Solution Approach 1:

The patent employs hydraulic actuators instead of conventional spring-driven mechanical actuators to provide the necessary closing force. The hydraulic system uses fluid pressure to actuate the valve closure mechanism, enabling sufficient cutting and closing forces to be generated within a more compact footprint. This hydraulic actuation system includes hydraulic lines connecting to the valve mechanism and utilizes the incompressibility of hydraulic fluid to transmit force efficiently.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the physical parameters of the actuation system by transitioning from elastic spring force to hydraulic pressure. This parameter change allows for more compact design because hydraulic systems can generate high forces in smaller volumes compared to spring mechanisms. The hydraulic pressure can be controlled and adjusted to provide the required closing force without the large mechanical dimensions of spring actuators.

Inventive Principle:
Principle #35Parameter changes

2Length of stationary object

If the valve is designed with a low profile to reduce footprint, then transport and installation costs decrease, but sufficient actuation force for closure and cutting cannot be ensured

Engineering Contradiction:
Improvevalve heightVSAvoidvalve closure reliability
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The low-profile valve design incorporates hydraulic actuators that deliver reliable closing forces despite the reduced overall height. The hydraulic system compensates for the compact dimensions by using high-pressure fluid to generate the necessary actuation force. The hydraulic lines and actuator mechanisms are arranged within the constrained vertical space while maintaining sufficient force output for reliable valve closure and obstruction cutting.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent redistributes the actuation system components in alternative spatial arrangements to achieve the low-profile configuration. Instead of vertical stacking that increases height, the hydraulic components are arranged horizontally or in compact three-dimensional configurations that maintain actuation force while reducing overall valve height. This dimensional reconfiguration allows reliable force generation within a compact footprint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If space is minimized for modular valve design, then transport and installation become more efficient, but room for additional actuators for reopening operations is unavailable

Engineering Contradiction:
Improveinstallation efficiencyVSAvoidactuator configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The hydraulic actuation system is designed with multi-functionality to handle both initial valve closure and subsequent reopening operations. The same hydraulic infrastructure, including lines and pressure sources, serves dual purposes: providing closing force for the primary safety function and providing reopening force when needed for well-killing operations. This eliminates the need for separate, space-consuming actuator systems for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the closing and reopening actuation capabilities into a single integrated hydraulic system. Rather than installing separate spring-driven actuators for closure and reopening functions, the design combines these functions into one hydraulic actuation mechanism. This consolidation reduces the overall space requirement while maintaining the capability to perform both closing and reopening operations as needed.

Inventive Principle:
Principle #5Merging (Combining)

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 reliable closure and reopening of the valve to prevent hydrocarbon leaks and ensure well control, maintaining safety and efficiency in subsea operations while minimizing the overall footprint and cost of the safety valve system.

Implementation Method 1

a first accumulator for actuating the valve to the closed position

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

a second accumulator for actuating the valve to the open position

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 3

a monolithic piston that can cut through obstructions

Methodology Applied
Scientific EffectHydraulic force: Pressure Increase

Data Source

PatentEP3578750B1Fail-safe valve arrangement
Publication Date: 2021.04.28 ONESUBSEA IP UK LTD
  • EP3578750B1 patent drawingFigure 1
  • EP3578750B1 patent drawingFigure 2
  • EP3578750B1 patent drawingFigure 3A~3C

AI summary

A hydraulic arrangement for a fail-safe valve (100). The arrangement allows for compact actuation of a fail-safe valve through accumulators. The arrangement supports automatic closure of the valve in the emergent circumstance of any loss of hydraulic control above the valve. Additionally, the arrangement (100) also allows for a technique of re-opening the vale for long term killing of a well (280) in direct response to the introduction of kill fluid without requiring any added complex interventional measures.