MCE Deepwater Development 2016

Subsea Produced Water Separation with SpoolSep: A Robust and Efficient Pipe Solution for a Wide Range of Deepwater Applications

Sadia SHAIEK R.HALLOT, S. ANRES

PAU, FRANCE • 5-7 APRIL 2016

MCE Deepwater Development 2016

AGENDA  Subsea Oil/Water Separation  SpoolSep Principles  Installation and Maintenance  Qualification tests  Conclusion

MCE Deepwater Development 2016

Subsea Oil/Water Separation  Subsea Produced Water Separation and Re-Injection

Subsea PWRI station Wells

• Increase recovery • Debottleneck topsides • Allow new tie-back to existing facility

 SpoolSep for Subsea Bulk Water Removal

• Made of several horizontal pipes working in parallel • Dedicated to deep/ultra-deep waters & high internal pressure applications • High flowrates

To surface facility Oil & Gas

To reservoir network

WD (m) 2000

Troll Pilot 340m WD 60 kbpd

SpoolSep

1500

Tordis 210m WD 100 kbpd

1000

500

0

50

100

Flowrate (kbpd)

Marlim 900m WD 20 kbpd

MCE Deepwater Development 2016

SpoolSep Principles  Main incentives

• Gravity-based Separation (field proven & robust process ) • Made of long parallel pipes with reduced thickness compared to large pressure vessels to cope with Deep & Ultra Deepwaters • Higher interfacial areas / lower rising distance for oil droplets (improved efficiency) • Good slug handling capabilities • Modular system : based on deepwater spools design • Flexible design to cope with wide range of inlet parameters

 Design principles

• Ensure equal fluid distribution • Same Process control philosophy as per single vessel • Provide required residence time for efficient oil/water separation

Typical spool installation sequence

MCE Deepwater Development 2016

SpoolSep Principles Typical Performances Spool outlet : several options  Independent outlet for each phase  Oil and gas recombination (stand pipe) + water outlet

Separation in mainpipe Gas

Stand pipe for • Oil level regulation • Gas & Oil recombination

Oil

Design Process criteria: • Phase velocity • Residence time / Cut-off diameter Selection of: • Number of spools • Spool diameter • Spool length

Water

Downstream bulk separator • Maximum OiW: 1000-2000 ppm • Maximum WC in oil stream: 15% Re-injection requirements • OiW: 20-100 ppm • TSS: 1 to 10 ppm • Solid particle size: 1-50µm

Water

Feedline

Base case stand pipe

Gas+ Oil

All individual outlets are commingled into a single outlet by phase Flow Splitter

Multiphase production from wells

Heavy Collector

Water Injection Pumps (O/W interface control)

Light Collector

Inlets & Outlets in the same area

Oil and Gas exported to surface (MPP) or separately

MCE Deepwater Development 2016

Subsea Station Design  Subsea Station Architecture • 1 or 2 foundations • •

1 for the station with all the process 1 smaller for pipes support (if needed)

• 1 subsea station with connecting all the equipments • •

All active parts gathered on same structure Standard integration and test principle

 Separation spools modules

• Within typical spool size envelop • Optimization of layout with compact connection • Retrievable by IMR vessels

Artistic view of SpoolSep Separation Station

MCE Deepwater Development 2016

Separation Spool Module Separator Outlet Height 4 to 6 m

Spool Outlet Feed Line OD 8” typ.

Separator Inlet

Spool Overview

1 off 3-bores clamp connector Or 1 off dual-bore clamp connector + 1 off single bore clamp connector

Pipe separator OD 18” to 50” typical

Spool Inlet

Aker Solutions

MCE Deepwater Development 2016

Installation and Maintenance

 Typical subsea module handling  Optimized connection for easier ROV operation  Standard installation sequence  Easy Spool recovery

MCE Deepwater Development 2016

Qualification Tests

Testing Flow loop

 Phase 1: Design Feasibility

• Fluid distribution & level symmetry • Gravity separation efficiency o o o

Tests loop built with 4 spools at reduced scale (200mm ID, 18m long) Model oils/Tap Water/Air Flows at ambient conditions for visualization Variation of operating conditions: flowrates / WC/ GVF/ shear level

Annular Outlet

• Sand settling & flushing characterization Separation spool

 Phase 2 : Design improvements & process criteria validation • Comparison of several geometries to further improve performances o o

Tests on each spool arranged with specific outlet Internals

Separated outlets

Feedline size

Perforated Plates

Return zone

MCE Deepwater Development 2016

MCE Deepwater Development 2016

Qualification Tests  Characterization of Horizontal Flow Patterns  Gas/Liquid Flows

Slug Flow Stratified Smooth Flow Stratified Wavy Flow

• • •

Stratified Flows • ST & MI • D O/W & W •

Gas / liquid horizontal flow patterns

1.E-01 1.E-02 1.E-03 1.E-04

Feedline mainpipe

1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+02 Spools Feedline N°1 1.E+01 1.E+00

1.50

Dispersion

1.25

1.E-05

ST & MI

1.00 0.75 0.50 0.25 0.00 0.0

Feedline Slug Flow mainpipe

Stratified Smooth Flow mainpipe

D W/O D O/W D W/O & O/W

1.75

Gas Froude number (-)

Vsliquid (m/s)

Slug Flow

Stratified Wavy Flow

Liquid Froude number (-)

• • •

 Liquid/Liquid Flows

0.2

0.4

WC

0.6

0.8

1.0

 Symetrical behaviour whatever the flow regimes  Assessment of flow regimes impact on performances and level control requirements  Definition of velocity criteria to ensure separated phases with required quality

MCE Deepwater Development 2016

Qualification Tests Rw (-)

 Validation of Flow Distribution / Level Symmetry & Stability 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00

Spool1 Spool3

0

spool2 Spool4

Spool1

Spool2

Spool3

Spool4

• Equal fluid distribution and balanced phase composition inside each spool • Symmetrical behavior of spools: validation of the base principle for level control philosophy • High level stabilty at separation conditions

10 20 30 Injected water flowrate (m3/h)

5000 5000

2.4

4500 4500

2.2

4000 4000

2.0

Ratios dv50/dst & dv90/dst

OiW Canty (ppmv)

 Design Criteria for SpoolSep Sizing 3500 3500 3000 3000 2500 2500 2000 2000 1500 1500 1000 1000

8 8

10 10

Water real velocity Spool N°1 (cm/s)

12 12

• Assessment of design criteria for the range of 100 to 2000 ppmv Oil in Water contents

1.2 1.0 0.8 0.6 0.4 0.0

6 6

Dv90 125µm

1.4

00

4 4

Dv90 63µm

1.6

0.2 2 2

dv90/dstokes

1.8

500 500 0 0

dv50/dstokes

0.0

2.0

4.0

6.0

8.0

Water real velocity

10.0

12.0

 Tests have confirmed separator operability giving design criteria to achieve required performance

MCE Deepwater Development 2016

Qualification Tests

 Tests conditions:

 Sand transport depends on: o

Liquid velocity and viscosity (Re)

 Critical velocity, Vc  Vc increases with increased viscosity

o

Sand granulometry

 Pre-installation of a sand bed in a 110 mmID pipe  2 particle sizes: d50 64µm & 248µm - 2650 kg/m3  Oil or water wetted sand  2 sand bed heights (10%-30% HU)  Flowing with different fluids Fluid velocity

 Vc increases with increased particle size

o

Carrier fluid flow pattern

 At low velocity, no impact of gas (if stratified flow)  At high velocity, easier transport under slugging flows

Suspensions

Moving Bed

Stationary flow

o

Pipe slope has a significant impact on sand transport

No motion

 Sand handling optimization (no need for internals)

Solid-Liquid Flow patterns

MCE Deepwater Development 2016

CONCLUSION  As part of Subsea Processing systems, the SpoolSep brings robust solution to PWRI applications in deepwater

SpoolSep Subsea Station

 Each separation spool can be installed and retrieved easily by subsea connectors  Confirmation of stability and symmetry of flows within separation spools  Reliable design to achieve required performances for water re-injection  Better understanding of criteria for efficient sand transport by fluid flowing  SpoolSep design flexibility (spool number, diameter and length) allows to accommodate wide range of requirements and conditions  On-going JIP with TOTAL & PETROBRAS

SpoolSep Model