Subsea Storage Unit Buoyancy Control for Stable Cargo

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Solution Overview

Problem

Offshore storage space limitations in subsea environments hinder timely maintenance and equipment delivery to subsea hydrocarbon production sites, leading to costly delays and safety risks due to the inefficiency of current storage solutions, such as floating containers that are unsuitable for extended use due to exposure to wind, waves, and currents.

Innovation Solution

A subsea storage unit with a pressure hull, ballast compartments, and remotely controlled ballasting pumps, allowing controlled buoyancy and anchoring, combined with a seabed facility and automated connection systems for efficient deployment and retrieval, enabling stable and secure storage of cargo containers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If floating containers are used for offshore storage, then storage space is provided, but the containers are exposed to wind, waves and currents making them unsuitable for extended storage

Engineering Contradiction:
Improvestorage spaceVSAvoidstorage stability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The storage system is divided into separate functional components: floating containers for storage, independent anchoring systems for stability, and mooring lines for positioning. This segmentation allows each component to be optimized independently - the containers provide storage volume while the anchoring system ensures stability during extended storage periods

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The anchoring system acts as a counterweight mechanism, with anchors weighing 50-100 kg providing downward force to counteract the buoyant floating containers. This creates a balanced system where the containers remain stable at the water surface despite exposure to environmental forces like wind and waves

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Ease of operation

If supply boats are used to transfer articles, then delivery is possible, but the operation is costly and dependent on weather

Engineering Contradiction:
Improvearticle transfer capabilityVSAvoiddelivery time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The floating containers are pre-positioned near the offshore unit before maintenance is needed. Spare parts and tools are loaded onto the containers in advance and kept ready for immediate transfer. When maintenance is required, the containers can be quickly moved to the offshore unit without waiting for supply boats or weather conditions

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The floating containers serve as an intermediary storage platform between the shore and the offshore unit. Instead of direct supply boat transfers, articles are first loaded onto the containers which then serve as a mobile warehouse, enabling faster and more flexible delivery to the offshore unit

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If the subsea vessel collects articles from onshore location, then storage needs are met, but this is a costly and undesirable operation

Engineering Contradiction:
Improvearticle storageVSAvoidoperational cost
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The storage system moves from a single-dimension approach (shore-based storage) to a multi-dimensional solution by deploying floating containers in the water column near the offshore unit. This creates a new spatial dimension for storage that is closer to where articles are needed, eliminating the need for expensive vessel trips to collect spare parts

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

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

The solution provides a stable, secure, and efficient means to store and deploy maintenance equipment, reducing logistical challenges and ensuring timely delivery of critical supplies to subsea sites, enhancing operational safety and reducing costs associated with delayed deliveries.

Implementation Method 1

the storage unit buoyancy is controllable by the plurality of ballast compartments and ballasting pumps

Methodology Applied
Scientific EffectBuoyancy control through ballasting: Archimedes' Principle (Buoyancy)

Data Source

PatentEP3524541B1A subsea storage unit, system and method therewith
Publication Date: 2023.08.30 SUBSEA LOGISTICS
  • EP3524541B1 patent drawingFigure 1~2
  • EP3524541B1 patent drawingFigure 3~4
  • EP3524541B1 patent drawingFigure 5~7

AI summary

A subsea storage unit (15; 15'; 15") comprises a pressure hull (1) having a cargo hold (5) configured for storing cargo (3, 7). The pressure hull has a movable hatch (4), providing access to the cargo hold; and a base (2; 8) configured for supporting the storage unit on a seabed (B). The unit also comprises suspension means (11a, b, 35), whereby the storage unit may be lifted and lowered in a body of water, and ballasting means. A seabed facility (30), configured for receiving and accommodating at least one subsea storage unit, is also provided.