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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
2
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
3
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
4
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
5
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
6
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
7
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
8
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
9
Absolute performance for extreme environments