Compact In-Line Pipeline Accessory With Foldable Mudmat Support

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Solution Overview

Problem

Current marine pipelaying techniques face challenges in integrating large in-line accessory structures into pipelines, particularly due to space constraints on pipelaying vessels and the need for stable mudmat foundations on soft seabeds, which limits the size and stability of accessories that can be deployed.

Innovation Solution

The design of a compact in-line accessory structure with a subsea foundation, a frame, and elongate pipe sections, featuring inclined branches and foldable mudmats that expand for stability, allowing for reduced size and lower center of gravity, enabling easier passage through vessel constraints and stable deployment on the seabed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If large in-line accessory structures are integrated into pipelines, then operational flexibility and field layout capabilities are improved, but space constraints on pipelaying vessels and stability on soft seabeds worsen

Engineering Contradiction:

Improveoperational flexibilityVSAvoidstructure size

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The structure is divided into separate components: the pipeline with accessory is fabricated separately with a reduced envelope, then the mudmat foundation is added independently during installation. This segmentation allows the pipeline portion to fit vessel constraints while the foundation provides seabed stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mudmat foundation extends the structure into the horizontal plane on the seabed, providing stability through lateral spread rather than vertical height. This dimensional change allows large accessories to be supported without increasing the vertical envelope required during pipelaying operations.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If accessories are made larger to provide operational flexibility, then field layout capabilities are improved, but stability on soft seabeds worsens

Engineering Contradiction:

Improvefield layout capabilitiesVSAvoidstability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mudmat foundation acts as an intermediary between the large accessory and the soft seabed, distributing the load over a larger area to prevent excessive settlement while allowing the accessory itself to maintain its large size for operational flexibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If accessories are constrained to smaller sizes to fit vessel space, then ease of installation is improved, but operational flexibility deteriorates

Engineering Contradiction:

Improveease of installationVSAvoidoperational flexibility

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pipeline and accessory are fabricated together in advance with a compact envelope suitable for vessel installation, then the mudmat foundation is added during the installation process. This preliminary fabrication ensures the structure fits vessel space constraints while still achieving the required operational flexibility.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If mudmats are made larger to support heavy accessories, then stability on soft seabeds is improved, but vessel space requirements and installation complexity worsen

Engineering Contradiction:

ImprovestabilityVSAvoidinstallation complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mudmat is designed to be deployable during the installation process, transitioning from a compact state during transport to a fully deployed stable foundation on the seabed. This dynamic deployment allows large mudmats to be used without permanently increasing vessel space requirements.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11448341B2Pipelaying

Publication Date: 2022.09.20 SUBSEA 7 DO BRASIL SERVICOS LTDA

AI summary

An in-line accessory structure for a subsea pipeline has an elongate pipe section arranged to be integrated into the pipeline, hence defining a flow axis through the structure. A branch has a lower end in fluid communication with the pipe section and an upper end in fluid communication with a connector hub. The structure further has a subsea foundation such as a mudmat, arranged to support the structure installed orientation. When the structure is in that orientation, the branch inclines inwardly from its lower end toward its upper end in a transverse direction, toward an upright longitudinal plane containing the flow axis.