Double-Walled Subsea Storage for Barrier Fluid Separation Control

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Solution Overview

Problem

Existing subsea storage systems for water miscible fluids face challenges in maintaining effective separation between the fluid and seawater, requiring costly disassembly or retrieval to the surface for maintenance, and lack efficient monitoring of fluid phases and barrier integrity.

Innovation Solution

A subsea storage system with a double-walled design using a barrier fluid to separate storage fluid from seawater, equipped with remote-controlled valves and a monitoring system comprising nucleonic, acoustic, inductive, and capacitive sensors to maintain phase separation and enable in situ maintenance, allowing for real-time monitoring and management of fluid levels and emulsified barriers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a barrier fluid is used to separate storage fluid from seawater in subsea storage, then separation effectiveness is improved, but maintenance complexity increases due to emulsification and barrier integrity monitoring requirements

Engineering Contradiction:

Improveseparation effectivenessVSAvoidmaintenance complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a monitoring system with sensors that continuously detect barrier fluid conditions, emulsification levels, and interface positions. This feedback enables real-time assessment of barrier integrity and triggers maintenance operations only when necessary, resolving the contradiction by making the complex monitoring system intelligent and condition-based rather than continuous and manual.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system uses automatic valve control and monitoring that enables the barrier fluid system to self-regulate and self-diagnose conditions. The remote-operated valves and sensors allow the system to maintain itself without requiring frequent manual intervention or complex maintenance procedures, reducing maintenance complexity while preserving separation effectiveness.

Inventive Principle:

Principle #25Self-service

2Ease of repair

If remote-operated valves and monitoring systems are installed for in situ maintenance, then maintenance accessibility is improved, but system complexity and cost increase

Engineering Contradiction:

Improvemaintenance accessibilityVSAvoidsystem complexity

Core Design Contradiction:

Ease of repairVSDevice complexity

Solution Approach 1:

The maintenance system is divided into modular components: remote-operated valves at specific positions, distributed sensors for different parameters, and a centralized control system. This segmentation allows each component to be independently optimized and maintained, reducing overall system complexity while improving maintenance accessibility through targeted, component-level operations.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If the subsea storage system uses a single-walled design without barrier fluid, then device complexity is reduced, but separation between water miscible fluid and seawater cannot be maintained

Engineering Contradiction:

Improvestructure simplicityVSAvoidphase separation

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The barrier fluid acts as an intermediary substance between the water miscible storage fluid and seawater. It creates a physical and chemical barrier that prevents mixing and emulsification, enabling phase separation in a system that would otherwise be incompatible. This intermediary approach maintains reliability without requiring complex mechanical separation devices.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effective separation and monitoring of fluid phases, facilitating in situ maintenance without the need for costly subsea disassembly, ensuring reliable operation and efficient management of the storage system.

Implementation Method 1

A subsea storage system with a double-walled design using a barrier fluid to separate storage fluid from seawater

Methodology Applied

Scientific EffectFluid immiscibility:

Implementation Method 2

equipped with remote-controlled valves and a monitoring system comprising nucleonic, acoustic, inductive, and capacitive sensors

Methodology Applied

Scientific EffectNucleonic detection:

Implementation Method 3

equipped with remote-controlled valves and a monitoring system comprising nucleonic, acoustic, inductive, and capacitive sensors

Methodology Applied

Scientific EffectAcoustic detection: Acoustics

Implementation Method 4

equipped with remote-controlled valves and a monitoring system comprising nucleonic, acoustic, inductive, and capacitive sensors

Methodology Applied

Scientific EffectInductive detection: Electromagnetic Induction

Implementation Method 5

equipped with remote-controlled valves and a monitoring system comprising nucleonic, acoustic, inductive, and capacitive sensors

Methodology Applied

Scientific EffectCapacitive detection: Capacitance

Implementation Method 6

Subsea storage offers the benefit of an environment where ammonia may be kept in liquid form by the natural pressure and temperature of the ambient sea

Methodology Applied

Scientific EffectPressure equalization:

Data Source

PatentEP4050248B1Subsea storage of a water miscible storage fluid

Publication Date: 2026.04.15 GRANT PRIDECO LP

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AI summary

The present invention relates to a subsea storage system for storing a water miscible storage fluid and methods related thereto.