Subsea ProfilersControl and Monitoring of Subsea SeparatorsControl and Monitoring of Subsea Separators

Magne K. HusebøMay 2008

Content:

Introduction to the Subsea Profiler

Content:

Introduction to the Subsea Profiler

Conceptual Requirements for Subsea Instruments

Tracerco Subsea Profiler technology

TORDIS Subsea application

Subsea Profiler experience

Target: Transperant Subsea Separation

Graphics: FMC Technologies

1958 - 200850 Years

Core business: industrial radioisotope technology applicationsProvides a variety of process diagnostics methodsProvides a variety of process diagnostics methods World-leading top-side separation measurement supplier20 years experience in sub-sea applications

Background

Subsea comes calling:

g

2002 - Heightened interest in radioisotope technology for Subsea separation

2004 - FMC Kongsberg Subsea engaged Tracerco to develop2004 - FMC Kongsberg Subsea engaged Tracerco to develop a Subsea Density Profiler

Statoil Tordis SSBI requirements established:Statoil Tordis SSBI requirements established:Design, Build, Qualify and Test Subsea Profiler by end of 2006

Technology based on well-proven Tracerco Profiler™ concept (top-side)

Design basis - reliability:Prior use in 100+ topside applications (2000-04)Muliple detector systemRedundant signal handlingg g

Subsea Conceptual Requirements

20 year design life

Subsea Conceptual Requirements

20-year design lifeRadioisotope technologyNo moving partsP l t t bl d t t l tProven long term stable detector elementsProven low maintenance requirements

Non invasive & retrievableNon-invasive & retrievableDetector system isolated from the processComponents retrievable via running tool

Dynamic process mappingReal time – less than 1 sec update of all detectorsMonitoring of all process phasesMonitoring of all process phasesProcess diagnostics capabilities

Subsea Profiler – design challenges

Marinisation challengesD bl HP b i t d > thi k ll

g g

Double HP barriers; water and process -> thick wallsTopside Profiler materials not acceptable sub-seaIsotope used topside to ”weak” for high pressure barriers E t i bilit lti t tiEnsure retrievability – ultimate contingency

Qualification for Subsea use:Expensive prototypeExpensive prototypeFull qualification and testing of prototype required:

- temperature, shock & vibration acc. to ISO 13628-6 EMC testing- EMC testing

- Leak & Hyperbaric tests

Provision for Factory AcceptanceProvision for Factory AcceptanceExpensive Test Rig requirementFunction & ESS testing

Transperant Subsea Separation by Tracerco Subsea ProfilerGraphics: FMC Technologies

Transperant Subsea Separation by Tracerco Subsea Profiler

Principle of Operation – System Overviewp p y

Profiler source and detector array housings placed into vessel ”dip pipes”:µP

µP

Gamma transmission

• 2 Vertical detector Geiger arraysµ µ arrays

• 1 Source array

• Heavy alloy collimation

E h i di t 2• Each source irradiates 2 tubes detectors

Principle of Operation – System Overview

µP

µP

Topsides

Tracerco PLCSubsea

Control

Module

(Modbus)

Client Control System

• Raw signals conditioned and counted in field device• Information passed to dedicated PLC providing signal handling,

configuration alarms/daignostics and data transfer to DCSconfiguration, alarms/daignostics and data transfer to DCS• Count rates from each detector are plotted as a function of elevation

Principle of Operation – System Overview

Retriveable detector system

System acceptance testing

• Full scale process lab set up to mimic separator fluids• Calibration and functionality testing• Sand/Water/Emulsion/Oil simulation • Detector probe inter-changeability testDetector probe inter changeability test

– Demonstration of system operation during detector replacement– Demonstration of successful operation upon replacement

• Intervention tool performance test• Intervention tool performance test

Tracerco Subsea Profiler, graphic outputGas

F ( )Tracerco Subsea Profiler, graphic output Foam (none)

Oil

E l iEmulsion

Water

SandSand

Real-time process profile

Process profile trend

TORDIS Subsea Improved Oil Recovery SeparationTORDIS Subsea Improved Oil Recovery Separation

Tracerco contribution:

• 1 dual detector Profiler for main separator control

• 3 single detector Profiler for sand management

• 1 single detector system to be held as spare

• Profilers delivered to test site Dec 2006Profilers delivered to test site Dec 2006• Site Integration Test carried out with FMC 2007• Subsea deployment of separation system Sept 2007

TORDIS SSBI Subsea Profiler Specification

• Depth 1500m (pressure tested to 188Bar)• 1 source array / 2 detectors

M t i l 25C D l ( d T t d i t lli t )• Material: 25CrDuplex (and Tungsten radoisotope collimators)• Length: 2m measurement range• Process distance, isotope vs detector: 300mm• Resolution: 28mm (56mm pitch)• Density accuracy better than 10 kg/m3

• Temperature: -10 °C to 125°C

• Supply 24 volts, 200mA per detector• Subsea comms Modbus RTU – 2 wire RS485 - to client SCU• Topsides PLC Modbus RTU from Client• Topsides PLC to client control system – Modbus TCP/IP• Design Life 20 years

TORDIS IOR SSBI Systemy

Process Control aspects:Process Control aspects:

P fil idProfiler provides:

• Liquid level measurement• Water level measurement• Sand level measurement

Process Shut-down measurement:Process Shut down measurement:

P fil idProfiler provides:

• Liquid level shut-down measurement (SIL2 compliant)• Water level shut-down measurement (SIL2 compliant)

Process monitoring aspects:Process monitoring aspects:

P fil idProfiler provides:

• Foam height / trending• Liquid level height / trending• Emulsion band development and trending• Water level height and trendingg g• Sand level and trending• Density profile for input to production calculation

Process monitoring aspects:Process monitoring aspects:

Process Graphic interface:

Profiler technology benefitsProfiler technology benefits

(compared to traditional level measurement)

Application benefitsppReliable, repeatable, information rich measurementsMeasures all phases over full range of instrument – caters for operational changesNot adversely affected by pressure & density variations or foamingy y p y gDesigned for ”zero” operational maintenance, no moving parts, non-contactBuilt-in redunndancy features and diagnostics

2 detector arraysTube loss compensation

Retrievable via ROV without affecting Process

Profiler technology benefitsProfiler technology benefits

(compared to traditional level measurement)

Process benefits – ‘Insight’ into process conditions:Throughput optimisation through improved controlSand jetting optimisation; timing and duration.j g p ; gMonitoring effect of chemical additives: emulsion breaker / anti-foam *)Allows evaluation of changing operating regimes (well behaviour)Avoids accidental oil discharge in produced waterAvoids accidental oil discharge in produced water

*) if applicable subsea

Development project – learning / experience

Lengthy design process:– client requirements, tooling, access preferences

N d d t d dNew codes and standards:– fabrication learning curve, establish supply chain.

Seek standard piping components; cost / lead time4 man years spent on design, engineering & project admin for the marinisation process

Summary

Fruitful cooperation cooperation with FMC Technologies resulted in successful ‘marinisation’ of the Tracerco ProfilerTM

Th S b T P fil i l d ll biliti f f lThe Subsea Tracerco Profiler includes all capabilities of successful topsides unit; all in a ISO13628 designSubsea Profilers Operating successfully at Tordis SSBINext project with FMC Technologies: Total Pazflor (West-Africa)

Insight OnsiteInsight Onsite

Thank You for Your attention!