MCE Deepwater Development 2016

PAU, FRANCE • 5-7 APRIL 2016

Extreme HP/HT well control

- Closing the technology gap

Chris Morrissey

MCE Deepwater Development 2016

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Introduction

With the continuing challenge to develop hydrocarbon fields which are deeper and hotter, closing the many technology gaps to provide safe and reliable operation remains an industry priority

Focus for this presentation

1. Hydraulic control of HP/HT wells – present experience & future challenges

2. Review limiting factors of hydraulic fluids and interactions with key

hardware

3. Environmental considerations

4. Power of collaboration

5. Technical recommendations and summary

HPHT Categories500 oF

260oC

Ultra HPHT

450 oF

232oC

Ultra HPHT

400 oF

204oC

Extreme HPHT

350 oF

177oC

HPHT

300 oF

149oC

10,000 psi 15,000 psi 20,000 psi 25,000 psi 30,000 psi

690 bar 1,034 bar 1,379 bar 1,724 bar 2,068 bar

CurrentLimit

AcknowledgementsThanks to Susannah Linington (Environmental Toxicologist) and Ashley Woods (Environmental Modelling Advisor)for environmental impact assessment and modelling

MCE Deepwater Development 2016

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Canyon Express

Akpo

Thunder Horse Kristin ErskineÅsgard Elgin Franklin West Franklin

Water-glycol Synthetic

120°C 135°C 140-150°C 150°C135-167°C 180°C 197°C

• Both water-glycol and synthetic based control fluids have their place in delivering high levels of reliability

• As an industry, the majority of experience is with water-glycol control fluids (>90% of subsea systems)

• However synthetic fluids have enabled access to increasingly challenging reservoirs

• Total West Franklin pushes the boundaries into extreme HP/HT conditions , 197°C (387°F) 2015 start-up

Existing Operational Experience

(CASTROL TRANSAQUA HT2) (CASTROL BRAYCO MICRONIC SV/3)

UPPER CONVENTIONAL HP / HT EXTREME HP / HT

Image reference – Offshore-technology.com

MCE Deepwater Development 2016

Thermal Effects on Control Equipment

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Subsea XTree

CHALLENGES

1. Heat soak into actuators (Thermal FEA)

2. Rod and Piston seals life

3. Fluid/Material compatibility data gaps

4. Tree insulation

MODERATE TEMP/PRESSURE – FLUID FLOW - ENVIRONMENTAL

Downhole Safety Valve

EXTREME TEMP/PRESSURE - TRAPPED FLUID - NO FLOW

Dynamic Seals

HydraulicPiston Assembly

Lower Metal-to-metal Hydraulic Seal

Upper Metal-to-metal Hydraulic Seal

Images courtesy of Halliburton

CHALLENGES

1. Long term extreme Temp/Press

2. Seal degradation and extrusion

3. Uncertain seal life (LET)

4. Friction – low fluid viscosity

MCE Deepwater Development 2016

Vendor Collaboration Key to Success

• Shared technical expertise and experience

• Aligned specifications and safety factors

• Early identification of risks and mitigations

• Faster journey to TRL4

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EXAMPLE 2

Fluid approval work with Completion Vendors(Cyclic DHSV testing to API 14A)

1. Functional test at 215°C ( 420°F) - Castrol Brayco Micronic SV/3 Fluid

2. Functional test at 232°C (450°F) – Castrol Synthetic Prototype Fluid

VALUE

• Shared learnings on test setup andcritical materials selection

• Increased the limit for reliableDHSV control to 450°F

EXAMPLE 1

Fluid /Materials qualification with XTree Vendor for XHP/HT application

• Estimated actuator heat soak require testing close to 150°C (300°F)

• Polymers, Elastomers, Metals , Coatings - including 10% Seawater

VALUE

• Early alignment of key test conditionsand pass/fail criteria

• Proved compatibility (Stage 1) beforestarting costly functional equipmenttests (Stage 2)

CLOSE COLLABORATION

Fluid VendorChemistsEngineersScientists

Project teamsSPS OEMsComponentSuppliers

MCE Deepwater Development 2016

Improved Environmental Assessment

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RISK Based Approach

• Used to model produced water and drilling fluid discharges – now able to model discharges from subsea trees

• Includes historical current, wind, bathymetry, and sea temperature data

• Provides quantitative assessment of the potential environmental risk posed by a chemical discharge

• The risk at each location and time is calculated by summing the risk from each chemical component

e.g. Water + MEG + each Additive (Inc. Qty)

Modelling TechniqueCurrent Approach

HAZARD Based Fluid Assessment• Generate biodegradation,

bioaccumulation and toxicity data by testing

• National regulator assesses data and highlights components which are non compliant and require phase-out -‘substitutable’

• Ranks components and products according to the country’s system (e.g. green, yellow, red, black for Norway, or A-E for UK OCNS).

HazardSomething with the potential to cause harm – intrinsic

property of the chemical

RiskThe Likelihood of Harm to the Environment

Resulting from Exposure to a Potential Hazard

Risk = Hazard x Exposure

CONSIDERATIONFOR CHEMICAL

QTY AND PHYSICALCHARACTERISTICS

NO YES

MCE Deepwater Development 2016

Fluid Discharge Characteristics – Fixed Depth

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Standard Modelling conditions used for fluid performance comparisons: Discharge point = 4 m above seabed, Volume = 30m3, Discharge Duration = 1 day, Modelling Duration = 3 days

SYNTHETIC FLUID

SV/E

600mWaterDepth

Vertical Profile Horizontal Profile

Seabed

1. Low fluid density drives rapid vertical dispersion

2. % Environmental Risk drops to below the no effect level after 1 hour

WATER BASED FLUID

600mWaterDepth

Seabed

Vertical Profile Horizontal Profile

1. Fluid density similar to seawater so little vertical dispersion

2. % Environmental Risk drops to below the no effect level after 3.5 hours

MCE Deepwater Development 2016

Subsea System Approach

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SCM

Deepwater(Likely Ex & Ultra HP/HT)

LP

HP

EXPERIENCE• Water based fluid• Open circuit systems

OPPORTUNITY• Synthetic fluid in open

circuit (simpler syst.)• Maximises reliability at

extreme temps, up to 500F

SCM

Conventional

LP

HP

EXPERIENCE• Water based & Synthetic control fluids• Open & Closed circuit systems• Water based – Lower cost, up to 167°C• Synthetic – closed systems, up to 200°C

ControlUmbilical

DHSV

SCM

Split Hydraulic System

LP

HP

HP Line

LP Line

NEW APPROACH• Water based fluid to

control LP XTree actuators (open circuit)

• Synthetic fluid to control HP high temperature DHSV

• Allows optimum fluid selection for each application rather than single compromise solution

Separate fluid linesIn single umbilical

MCE Deepwater Development 2016

Summary• A collaborative approach between equipment vendors and lubricant manufacturers is essential to

reduce risk, cost and time to achieve TRL4

• Moving beyond current HP/HT conditions may require new system architecture to meet the different needs of subsea and downhole control

• Synthetic fluids have the potential to deliver optimum reliability in all elements of the control system right up to ultra HP/HT

• Environmental modelling shows that synthetic fluids can potentially be used in open circuit systems, which improves simplicity, especially important for deep water

• Continued investment in R&D is imperative to be prepared for new developments beyond the current environment

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Absolute performance for extreme environments