Subsea Hydrate Removal via Pressure Modulator Vacuum

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Solution Overview

Problem

Conventional methods for removing hydrate plugs in subsea equipment are costly and complex, often requiring depressurization of entire flow lines, which can damage components and are inefficient.

Innovation Solution

A fluid system with a pressure modulator and pump configuration that creates a vacuum pressure to dislodge hydrate blockages, followed by a positive pressure to ensure removal, using a hydrate skid and jumper conduits to selectively communicate pressures to subsea equipment, allowing for targeted treatment and minimizing system disruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional depressurization methods are used to remove hydrate plugs, then hydrate removal can be achieved, but the entire flow line must be depressurized which increases system complexity and risks damaging components

Engineering Contradiction:
Improvehydrate removal effectivenessVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system segments the flow line by using a packer to isolate the hydrate-affected section from the rest of the flow line. This allows localized depressurization and hydrate removal in the isolated section without requiring depressurization of the entire flow line, thereby reducing system complexity and protecting components from pressure fluctuations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The packer acts as an intermediary device that creates a sealed isolation between the hydrate plug and the rest of the flow line. This intermediary element enables controlled access to the hydrate section for removal operations while maintaining pressure integrity in the remaining system, avoiding the need for full system depressurization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If full flow line depressurization is performed to remove hydrates, then hydrate plugs can be removed, but operational time increases and productivity decreases

Engineering Contradiction:
Improvehydrate removal effectivenessVSAvoidoperational efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

By segmenting the flow line with a packer to isolate only the hydrate-affected section, the system enables localized hydrate removal operations. This segmentation allows the rest of the flow line to remain pressurized and operational, significantly reducing the operational time required compared to full line depressurization and thereby improving overall productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The packer is positioned and the flow line is isolated before hydrate removal operations begin. This preliminary isolation action ensures that only the necessary section requires depressurization, allowing hydrate removal to be performed quickly and efficiently without shutting down the entire system, thus maintaining higher operational efficiency.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If hydrate inhibitors are added to remove hydrate plugs, then hydrate removal can be achieved, but the cost and complexity of the fluid system increases

Engineering Contradiction:
Improvehydrate removal effectivenessVSAvoidfluid system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system extracts and removes the hydrate plug physically through isolation and depressurization of the affected section, rather than relying on chemical inhibitors to prevent or dissolve hydrates. This extraction approach eliminates the need to manage hydrate inhibitor dosing, monitoring, and interaction with other fluid system components, thereby reducing fluid system complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system replaces chemical hydrate removal methods (using inhibitors) with a mechanical approach involving packer isolation and controlled depressurization. This mechanical substitution avoids the complexity of chemical fluid management, allowing for simpler fluid system operation while achieving reliable hydrate removal.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This method effectively removes hydrate blockages without the need for full depressurization, reducing damage and operational costs by applying precise pressure differentials to dislodge and eliminate hydrate plugs, ensuring efficient fluid flow and equipment operation.

Implementation Method 1

the pump is configured to provide a continuous fluid flow through a continuous fluid loop comprising the injection conduit, pressure modulator, and return conduit, wherein the pressure modulator comprises a reduced diameter section disposed between the inlet and the outlet, and wherein, in response to the provision of continuous fluid flow through the pressure modulator by the pump, a vacuum pressure is communicated to the piece of subsea equipment from the reduced diameter section of the pressure modulator to remove a hydrate blockage

Methodology Applied
Scientific EffectVacuum pressure differential: Pressure Gradient

Implementation Method 2

the pump is configured to communicate a positive pressure greater than the vacuum pressure to the piece of subsea equipment

Methodology Applied
Scientific EffectPositive pressure differential: Pressure Gradient

Data Source

PatentEP3287592B1Systems and methods for hydrate removal
Publication Date: 2021.05.12 ONESUBSEA IP UK LTD
  • EP3287592B1 patent drawingFigure 1
  • EP3287592B1 patent drawingFigure 2
  • EP3287592B1 patent drawingFigure 3

AI summary

A method for treating the formation of hydrates in a fluid system includes pumping a fluid at a substantially constant fluid flow rate through a hydrate removal system including a pressure modulator, communicating a vacuum pressure to a piece of subsea equipment from a pressure port of the pressure modulator, closing a valve in the hydrate removal system to cease the fluid flow through the hydrate removal system at the substantially constant fluid flow rate, and communicating a positive pressure greater than the vacuum pressure to the piece of subsea equipment in response to closing the valve of the hydrate removal system.