Subsea Manifolds

Documentation for subsea production manifold equipment in NeqSim.

Table of Contents

• Overview
• SubseaManifold Class
• Manifold Types
• Valve Skid Configuration
• Well Routing
• Usage Examples
• Design Standards
• Related Documentation

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Overview

Location: neqsim.process.equipment.subsea

A subsea manifold gathers production from multiple wells and routes it to flowlines for transport to the host facility. The SubseaManifold class models:

• Production headers for well gathering
• Test headers for individual well testing
• Service/utility headers for chemicals and hydraulics
• Valve skids with production and isolation valves
• Flowline connections to export pipelines

Class	Description
SubseaManifold	Multi-slot production manifold
SubseaManifoldMechanicalDesign	Mechanical design calculations

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SubseaManifold Class

Class Hierarchy

ProcessEquipmentBaseClass
└── SubseaManifold
    ├── enum: ManifoldType
    ├── static class: ValveSkid
    └── contains: Mixer (production/test headers)

Key Features

• Multi-Slot Design: Support for 2-12 well connections
• Production/Test Routing: Switchable flow paths
• Valve Skid Modeling: Individual well control
• Header Sizing: Based on total flow capacity
• Pigging Integration: Launcher/receiver connections

Constructor

import neqsim.process.equipment.subsea.SubseaManifold;

// Create 6-slot manifold
SubseaManifold manifold = new SubseaManifold("Manifold-A", 6);

// Configure design parameters
manifold.setWaterDepth(380.0);
manifold.setDesignPressure(350.0);
manifold.setDesignTemperature(120.0);
manifold.setHasTestHeader(true);

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Manifold Types

ManifoldType Enumeration

Type	Description	Application
PRODUCTION_ONLY	Single production header	Simple gathering
PRODUCTION_TEST	Production + test headers	Standard design
FULL_SERVICE	Production + test + injection	Complex fields
INJECTION	Water/gas injection only	IOR projects

Selecting Manifold Type

// Standard production with testing capability
manifold.setManifoldType(SubseaManifold.ManifoldType.PRODUCTION_TEST);

// Full service for complex operations
manifold.setManifoldType(SubseaManifold.ManifoldType.FULL_SERVICE);

// Injection manifold for water injection wells
SubseaManifold injManifold = new SubseaManifold("Injection Manifold", 4);
injManifold.setManifoldType(SubseaManifold.ManifoldType.INJECTION);

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Valve Skid Configuration

ValveSkid Inner Class

Each well slot has a valve skid with:

Component	Function
Production Valve (PV)	Route to production header
Test Valve (TV)	Route to test header
Crossover Valve (XV)	Header crossover capability
Isolation Valve (IV)	Emergency isolation

Configuring Valve Skids

// Get valve skid for slot 1
SubseaManifold.ValveSkid skid = manifold.getValveSkid(1);

// Configure well connection
skid.setWellName("Well-A1");
skid.setActive(true);
skid.setRouting("production");  // or "test"

// Connect stream
skid.setConnectedStream(well1Stream);

Valve Positions

Routing	PV	TV	Status
Production	Open	Closed	Normal production
Test	Closed	Open	Well testing
Shut-in	Closed	Closed	Well isolated

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Well Routing

Adding Wells to Manifold

// Add well streams to manifold
manifold.addWellStream(well1Stream);
manifold.addWellStream(well2Stream);
manifold.addWellStream(well3Stream);
manifold.addWellStream(well4Stream);

// Check well count
int connectedWells = manifold.getConnectedWellCount();
System.out.println("Connected wells: " + connectedWells + "/" + manifold.getNumberOfSlots());

Routing Wells to Test

// Route well 2 to test header
manifold.routeWellToTest(2);

// Route well back to production
manifold.routeWellToProduction(2);

// Route all wells to production
manifold.routeAllToProduction();

Getting Output Streams

// Run manifold
manifold.run();

// Get output streams
StreamInterface productionStream = manifold.getProductionStream();
StreamInterface testStream = manifold.getTestStream();

System.out.println("Production rate: " + productionStream.getFlowRate("kg/hr") + " kg/hr");
System.out.println("Test rate: " + testStream.getFlowRate("kg/hr") + " kg/hr");

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Usage Examples

Example 1: Basic Manifold Setup

import neqsim.thermo.system.SystemSrkEos;
import neqsim.process.equipment.stream.Stream;
import neqsim.process.equipment.subsea.SubseaManifold;

// Create well fluids
SystemSrkEos fluid1 = new SystemSrkEos(353.15, 180.0);
fluid1.addComponent("methane", 75.0);
fluid1.addComponent("ethane", 10.0);
fluid1.addComponent("propane", 5.0);
fluid1.addComponent("n-heptane", 10.0);
fluid1.setMixingRule("classic");

// Create well streams
Stream well1 = new Stream("Well-A1", fluid1.clone());
well1.setFlowRate(20000.0, "kg/hr");
well1.run();

Stream well2 = new Stream("Well-A2", fluid1.clone());
well2.setFlowRate(25000.0, "kg/hr");
well2.run();

Stream well3 = new Stream("Well-A3", fluid1.clone());
well3.setFlowRate(18000.0, "kg/hr");
well3.run();

// Create 6-slot manifold
SubseaManifold manifold = new SubseaManifold("Manifold-A", 6);
manifold.setWaterDepth(380.0);
manifold.setDesignPressure(350.0);
manifold.setHasTestHeader(true);

// Add wells
manifold.addWellStream(well1);
manifold.addWellStream(well2);
manifold.addWellStream(well3);

// Run manifold
manifold.run();

// Get commingled production
StreamInterface production = manifold.getProductionStream();
System.out.println("Total production: " + production.getFlowRate("kg/hr") + " kg/hr");

Example 2: Well Test Operation

// Create manifold with wells
SubseaManifold manifold = new SubseaManifold("Manifold-B", 4);
manifold.addWellStream(wellA);
manifold.addWellStream(wellB);
manifold.addWellStream(wellC);
manifold.addWellStream(wellD);

// Normal production mode
manifold.routeAllToProduction();
manifold.run();
System.out.println("Production mode:");
System.out.println("  Production: " + manifold.getProductionStream().getFlowRate("kg/hr") + " kg/hr");

// Test Well C individually
System.out.println("\nTesting Well C:");
manifold.routeWellToTest(3);  // Well C is slot 3
manifold.run();

StreamInterface testStream = manifold.getTestStream();
System.out.println("  Well C rate: " + testStream.getFlowRate("kg/hr") + " kg/hr");
System.out.println("  Well C GOR: " + calculateGOR(testStream) + " Sm3/Sm3");

// Return to normal production
manifold.routeAllToProduction();

Example 3: Manifold with Header Sizing

// Create manifold
SubseaManifold manifold = new SubseaManifold("Main Manifold", 8);
manifold.setWaterDepth(500.0);
manifold.setDesignPressure(400.0);
manifold.setDesignTemperature(130.0);

// Set header sizes (inches)
manifold.setProductionHeaderSize(12.0);  // 12" production header
manifold.setTestHeaderSize(8.0);         // 8" test header
manifold.setServiceHeaderSize(4.0);      // 4" service header

// Configure slot piping
manifold.setSlotPipeSize(6.0);  // 6" from each well slot

// Get mechanical design
SubseaManifoldMechanicalDesign design = manifold.getMechanicalDesign();
design.setMaterialGrade("6Mo");
design.calcDesign();

System.out.println("Manifold weight: " + design.getWeight() + " tonnes");

Example 4: Complex Field Development

import neqsim.process.processmodel.ProcessSystem;

// Create process system
ProcessSystem subsea = new ProcessSystem("Subsea System");

// Create two manifolds
SubseaManifold manifoldNorth = new SubseaManifold("North Manifold", 6);
SubseaManifold manifoldSouth = new SubseaManifold("South Manifold", 6);

// Configure both
for (SubseaManifold m : Arrays.asList(manifoldNorth, manifoldSouth)) {
    m.setWaterDepth(450.0);
    m.setDesignPressure(380.0);
    m.setHasTestHeader(true);
}

// Add wells to north manifold
manifoldNorth.addWellStream(wellN1);
manifoldNorth.addWellStream(wellN2);
manifoldNorth.addWellStream(wellN3);

// Add wells to south manifold
manifoldSouth.addWellStream(wellS1);
manifoldSouth.addWellStream(wellS2);
manifoldSouth.addWellStream(wellS3);
manifoldSouth.addWellStream(wellS4);

// Run manifolds
subsea.add(manifoldNorth);
subsea.add(manifoldSouth);
subsea.run();

// Get total field production
double northRate = manifoldNorth.getProductionStream().getFlowRate("kg/hr");
double southRate = manifoldSouth.getProductionStream().getFlowRate("kg/hr");
System.out.println("Field production: " + (northRate + southRate) + " kg/hr");

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Design Standards

Applicable Standards

Standard	Title
API RP 17G	Completion/Workover Risers
API RP 17N	Subsea Production System Reliability
DNV-ST-F101	Submarine Pipeline Systems
NORSOK U-001	Subsea Production Systems

Design Parameters

Parameter	Typical Range	Unit
Number of Slots	2-12	-
Water Depth	50-3000	m
Design Pressure	345-1034	bar
Design Temperature	-29 to 175	°C
Design Life	20-30	years

Material Selection

Component	Material	Application
Headers	25Cr SDSS	Sour, high pressure
Valves	Inconel 625	Corrosion resistant
Structure	Carbon steel	Non-wetted
Piping	6Mo, 25Cr	Sour service

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Header Sizing Guidelines

Production Header

\[D_{header} = \sqrt{\frac{4 \cdot Q_{total}}{\pi \cdot v_{max}}}\]

Where:

• $Q_{total}$ = Total volumetric flow rate
• $v_{max}$ = Maximum allowable velocity (typically 15-20 m/s for gas)

Typical Sizes

Wells Connected	Header Size
2-4	8-10”
4-6	10-12”
6-8	12-14”
8-12	14-16”

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Related Documentation

• Subsea Trees - Christmas tree modeling
• Subsea Boosters - Subsea pumping
• Umbilicals - Control and chemical supply
• Subsea Equipment Overview - All subsea equipment

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API Reference

SubseaManifold

// Constructors
SubseaManifold(String name)
SubseaManifold(String name, int numberOfSlots)

// Configuration
void setManifoldType(ManifoldType type)
ManifoldType getManifoldType()
void setWaterDepth(double depth)
void setDesignPressure(double pressure)
void setDesignTemperature(double temperature)
void setHasTestHeader(boolean hasTest)

// Header sizing
void setProductionHeaderSize(double inches)
void setTestHeaderSize(double inches)
void setServiceHeaderSize(double inches)
void setSlotPipeSize(double inches)

// Well connections
void addWellStream(StreamInterface wellStream)
int getConnectedWellCount()
int getNumberOfSlots()

// Valve skids
ValveSkid getValveSkid(int slotNumber)

// Well routing
void routeWellToProduction(int slotNumber)
void routeWellToTest(int slotNumber)
void routeAllToProduction()

// Output streams
StreamInterface getProductionStream()
StreamInterface getTestStream()

// Mechanical design
SubseaManifoldMechanicalDesign getMechanicalDesign()

// Run simulation
void run()
void run(UUID id)

ManifoldType Enum

enum ManifoldType {
    PRODUCTION_ONLY,
    PRODUCTION_TEST,
    FULL_SERVICE,
    INJECTION
}

ValveSkid Class

class ValveSkid {
    int getSlotNumber()
    String getWellName()
    void setWellName(String name)
    boolean isActive()
    void setActive(boolean active)
    String getRouting()
    void setRouting(String routing)
    StreamInterface getConnectedStream()
    void setConnectedStream(StreamInterface stream)
}