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Upstream Research
Design and Performance Testing of an Integrated, Subsea Compact Separation System for Deep-water Applications
Ed GraveFractionation & Separation Advisor Houston, TX USA
MCE Deepwater DevelopmentApril 8 & 9, 2014Madrid, Spain
Upstream Research
Global Liquids Supply By Type
Oil Sands
NGLs
Deepwater
Tight Oil
BiofuelsOther Liquids
Business IncentivesM
illio
ns o
f oil-
equi
vale
nt b
arre
ls p
er d
ay
2005 Deepwater ~ 3%
2040 Deepwater ~ 12%
Source: 2013 The Outlook for Energy: A View to 2040 (www.exxonmobil.com)
ExxonMobil Resource Base Distribution In Percent Oil-Equivalent Barrels
About 11% of Resources
Source: 2013 Financial & Operation Review(www.exxonmobil.com)
2040 Deepwater Contribution
= ~ 14 MBDOE
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Please refer to disclaimer note regarding forward projections within the referenced sources below:
ExxonMobil Subsea Compact Separation SystemExxonMobil Upstream Research Company (URC) designed and is testing a compact separation system for application in 3000m water depth and internal pressures up to 690 barEM qualification philosophy is to qualify for a wide range instead of specific field conditions to reduce timeline of applicationRobust, flexible to inlet fluids, and scalable
API Gravity: 19˚‐38˚Oil Rate: 60 kBPD/trainGas Rate: 1250 – 4000 Sm3/dayWater Cut: 0‐90%Slug Size: 5m3
Currently being qualified at ProlabNL(3) Crudes with API 19˚, 28˚ & 38˚Scaled to 10‐15 kBPDMethane Gas at 45 barsGas Rate: 33‐497 Am3/hrWater cuts 10‐70%Slug Tests: 0.2 to 0.6m3 Upstream Research
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Simplified Schematic of ExxonMobil Subsea Compact Separation System
being tested at ProLabNL.
ExxonMobil Subsea Compact Separation System
OilURC Inlet Gas/Liquid Slug‐Catcher
URC Liquid/Liquid Pipe Separator and Level Controls
Inlet
Gas
Water
ASCOM Inline De‐sander
ASCOM Hiper™ MixedFlow 2‐stage de‐oiling Hydrocyclones and Canty Oil/Water Monitors
Cyclonic Inline Gas Polisher
Reject
Fast‐Acting MokveldSubsea Control Valve
Liquid Slug Generator
FMC‐CDS IEC tested at FMC separately
Aker CEC™
OiWMonitors
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High-Pressure Testing at Steady-State Conditions
ExxonMobil Multitube/Subsea Slug-Catcher
Test Results/Findings:• Minimal liquid carry-over in majority of test points; gas outlet quality improved at lower liquid levels• Liquid outlet quality improved at higher temperature (i.e., lower viscosity in oil phase) and lower oil flow rates• Determined optimum liquid level and control scheme to minimize both liquid carryover and gas carryunder
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Liquid velocity (m/s)
Effect of Water Cut, Temperature, and Liquid Velocity on Gas Carry-under
20% WC at 50C 70% WC at 50C
20% WC at 70C 70% WC at 70C
Tested at high-pressure (45 barg) in ProLabNL’s HP flow loop facility with natural gas, crude & water; test parameters included liquid level, fluid properties, crude type and flow variations (flow rate, GLR, slugging)
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Effect of Liquid Level on Gas Carry-under
GVF Slug Catcher Level Slug CatcherAdditional CFD analysis performed prior to tests at ProLabNL
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High-Pressure Testing at Steady State Conditions
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• A compact, in-line cyclonic separation device for liquid removal from gas-dominated streams; rated for 3000 m water depth and high internal pressures
• Applicable for liquid loading between 0-15 vol%
Results/Findings:• Better separation efficiency during high-pressure tests at higher liquid loadings (> 1.7 vol%) and gas rates (>
200 m3/hr)• Gas carry-under from ASCOM Monoline boot observed during high-pressure tests when liquid residence time
was low; degassing in vertical boot is not sufficient
ASCOM Monoline – Gas Polisher
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Effic
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LVF (%)
Medium Crude (All Test Runs)
100-150 m3/h 150-200 m3/h 200-250 m3/h 300-350 m3/h
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All data generated by or on behalf of ExxonMobil
Courtesy of Ascom Advanced Separation Company
Gas Carryunder- High Pressure Testing
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• Gas carry-under from ASCOM Monoline boot observed during high-pressure tests increased overall gas carryunder in the oil and increased emulsion height in the downstream pipe separator.
• Evaluated horizontal boot in low-pressure, model fluid tests; improves degassing at the same liquid residence time; no effect on liquid carry-over
Results/Findings:• Evaluated horizontal boot in low-pressure, model fluid tests; improves degassing at the same liquid residence
time; no effect on liquid carry-over• Horizontal boot requires fast response level instrument due to limited span length.• The horizontal boot design has not yet been tested in the high pressure loop
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Residence time (sec)
Medium Crude (All Test Runs)
Design Optimization-Low Pressure
ASCOM Monoline – Optimization
Vertical Boot
Horizontal Boot
All data generated by or on behalf of ExxonMobil
Courtesy of Ascom Advanced Separation Company
High-Pressure Testing at Steady-State Conditions
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Results/Findings:• Oil/water qualities highly dependent upon interface level; small changes in interface level lead to significant
changes in Oil in Water (OiW), as emulsion layer is pulled into water outlet• Oil/water qualities improved at higher temperature (i.e., lower viscosity in oil phase, less stable emulsion
layer), low or high water cuts, and lower liquid flow rates
Pipe separator tested at high-pressure (45 barg) in ProLabNL’s HP flow loop facility with natural gas and crude; test parameters included liquid level, fluid properties, and flow variations (flow rate, GLR, slugging)
WIO/OIW Along Pipe Separator LengthCrude with 40%WC at 35˚C
WIO/OIW Along Pipe Separator LengthCrude with 40%WC at 70˚C
Mixing w/ U-bend pipe separator studied for the large scale unit
ExxonMobil Pipe Separator
All data generated by or on behalf of ExxonMobil
Pipe Separator High-Pressure Testing at Steady-State Conditions NO Aker CEC™
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Heavy oil separation is challenging in compact separation system• Testing has shown that oil and water quality targets are difficult to meet –
requires reduced flow and/or additional heat or chemicals• Incorporating electrostatic coalescence in compact separation system is
expected to enhance performance. Aker CEC™ testing at ProlabNL on going• Aker CEC™ previously tested at Porsgrunn, Norway for the Hebron
qualification tests (2009) with a conventional separator Demonstrated increased separation efficiencies by factor of 5, reducing
residence times from 60 to 10 minutes Data limited to 10% WC and 80-100˚C
WiO/OiW for 2x velocity in Pipe SeparatorLighter Crude with 20%WC at 70˚C
WiO/OiW for 1x velocity vs Sample Points in Pipe SeparatorHeavier Crude with 20%WC at 70˚C
Aker CEC™ & ExxonMobil Pipe Separator
All data generated by or on behalf of ExxonMobil
ConclusionsThe ExxonMobil Subsea Compact Separation System proved to be very robust for a wide range of operating conditionsAs expected performance decreased significantly with heavy oilSlug Catcher ‐ Small variations in liquid level control in slug catcher affects both liquid carryover and gas carryunder. Gas carryunder increased emulsion in Pipe Separator
Horizontal boot in ASCOM Monoline enhanced degassingPipe Separator ‐ OiW concentration highly dependent on liquid level controlClosed most of the gaps with ExxonMobil Compact Separation System
ExxonMobil Multitube Slug CatcherASCOM Monoline Gas PolisherASCOM Inline De‐sander
Control system dynamic simulation can not be validated in a closed loop systemOil in Water monitors is still an open gap. Working with a number of vendors.
ExxonMobil Pipe SeparatorASCOM Deoiling SystemTracerco’s Profiler™
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Thank You!! Questions?
Upstream Research
Thank You! Questions?
Ed GraveFractionation & Separation Advisor [email protected]‐713‐289‐4770Houston, TX USA