Subsea Cooler Segmented Cooling Sections for Hydrate and Salt Management

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Solution Overview

Problem

Subsea coolers for hydrocarbons face issues with temperature regulation, leading to hydrate formation, waxing, scaling, and uneven fluid distribution, which can cause operational problems and reduce production efficiency, and existing technologies do not effectively address these challenges, including capacity regulation, sand and debris accumulation, and fouling detection.

Innovation Solution

A subsea cooler design with multiple cooling sections, inclined distributing pipes, and a bypass line, equipped with valve devices and temperature/pressure sensors for capacity regulation and fluid distribution, along with features like diffusers and mixers to ensure even fluid distribution and prevent fouling, and self-draining capabilities to manage sand and debris.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the process temperature is lowered to prevent hydrate formation and waxing, then hydrate and wax formation is prevented, but normal soluble salts may be deposited due to decreased solubility

Engineering Contradiction:
Improvehydrate and wax preventionVSAvoidsalt deposition
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The cooler is divided into multiple cooling sections (first cooling section, second cooling section, etc.) with different temperature zones. The first cooling section operates at a lower temperature to prevent hydrate and wax formation, while the second cooling section operates at a higher temperature to prevent salt deposition, thus resolving the contradiction between preventing hydrates/wax and avoiding salt precipitation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the cooler are assigned different thermal characteristics and operating temperatures. The first cooling section is designed for aggressive cooling to prevent hydrates and wax, while the second cooling section provides milder cooling to prevent salt deposition, allowing each local region to address specific problems appropriately

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If multiple cooling sections are added to achieve temperature regulation and prevent salt deposition, then salt deposition is prevented, but device complexity increases

Engineering Contradiction:
Improvesalt deposition preventionVSAvoidcooler structure complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The cooler is segmented into multiple cooling sections that can be independently controlled. Each section has its own temperature control capabilities, allowing precise regulation of the cooling process to prevent salt deposition while maintaining manageable complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooler incorporates dynamic temperature control across different sections, allowing the operating parameters to be adjusted based on process conditions. This dynamic capability enables the system to adapt to varying requirements and prevent salt deposition without requiring overly complex fixed-structure designs

Inventive Principle:
Principle #15Dynamics

3Reliability

If cooling capacity is increased to maintain lower process temperature, then hydrate formation is prevented, but energy consumption increases

Engineering Contradiction:
Improvehydrate formation preventionVSAvoidcooling energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

By dividing the cooling process into multiple sections with different temperature targets, the system avoids the excessive energy consumption that would result from uniformly aggressive cooling throughout the entire process. The first section provides intensive cooling where needed to prevent hydrates, while subsequent sections use milder cooling, thereby reducing overall energy consumption while maintaining hydrate prevention

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cooling temperature parameters are optimized and varied across different sections of the cooler. The first cooling section operates at lower temperatures to prevent hydrate formation, while the second cooling section operates at higher temperatures to prevent salt deposition, achieving effective hydrate prevention with optimized energy consumption

Inventive Principle:
Principle #35Parameter changes

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 design ensures efficient temperature regulation, prevents hydrate and wax formation, maintains even fluid distribution, and provides early warning signs of fouling, enhancing the operational reliability and efficiency of subsea compressor/pump stations.

Implementation Method 1

The cooling pipes are exposed to the surrounding sea water whereby the fluid flowing through the subsea cooler exchanges heat with the surrounding sea water

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

the fluid flowing through the subsea cooler exchanges heat with the surrounding sea water

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

The distributing pipes are inclined relative to a horizontal plane when the subsea cooler is installed on the seabed such that the fluid flows downwards from the primary distribution point toward the cooling sections

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2411625B1Subsea cooler
Publication Date: 2020.11.25 ONESUBSEA PROCESSING AS
  • EP2411625B1 patent drawingFigure 1
  • EP2411625B1 patent drawingFigure 2~4
  • EP2411625B1 patent drawingFigure 5~7

AI summary

There is disclosed a subsea cooler for the cooling of a fluid flowing in a subsea flow line. The subsea cooler comprises an inlet and an outlet which are connectable to the subsea flow line and at least two cooling sections arranged in fluid communication with the inlet and the outlet of the subsea cooler. Each cooling section includes a plurality of cooling pipes which are configured such that they exchange heat energy with the surrounding sea water when the subsea cooler is in use. The subsea cooler is further provided with valve means such that the flow of fluid through the cooling sections may be regulated individually. There is also disclosed a method for removal of accumulated wax, hydrates and sand and debris which has accumulated in the subsea cooler wherein separate cooling section are shut off whereby the temperature of the fluid flowing through the subsea cooler is increased thereby melting the wax and hydrates, and whereby the speed of the fluid flow through the subsea cooler is increased thereby jetting out sand and debris.