1. 41st Gas-Lift Workshop Houston, Texas, USA June 3 - 7, 2019
Challenges and Design Methodologies in Developing Gas Lift Systems for Deepwater Applications
Ganesh Balasubramanian - Project Manager, Schlumberger
Eric Lovie - Technical Director, Schlumberger
Shao Chong Oh - Product Line Manager, Schlumberger
2019 Gas-Lift Workshop
June 3 - 7, 2019

2. DESIGNING GAS LIFT FOR DEEPWATER PRESENTATION OVERVIEW
Engineering challenges in developing gas lift systems as application requirements have evolved
Inherent limitations in gas lift mandrel designs
Design / Yield Acceptance Criteria
Iterative Design Optimization (Achilles’ Heel Shift Technique)
Material Selection and Qualification
2019 Gas-Lift Workshop
June 3 - 7, 2019

3. 1) CHALLENGES Application Requirements Engineering Requirements
From on-shore rigs to Subsea and Deepwater terrains
Engineering Requirements
Increased Pressure and Temp. ratings
Higher metallurgies
Increased Production ID size
Special features (injection Ports)
Bypass slots for cables
Barrier technology with dual pockets
Design efficiency / reliability
Delivery Requirements
Shorter lead time (drawing board to rig floor)
2019 Gas-Lift Workshop
June 3 - 7, 2019

4. 2) GAS LIFT MANDRELS – REGIONS OF INTEREST
ECCENTRIC REGION TO HOLD GAS LIFT VALVE
Upper End - Threaded
Lower End - Threaded
Gas Lift Valve
Injected Gas
Produced hydrocarbons
2019 Gas-Lift Workshop
June 3 - 7, 2019

5. NON-UNIFORM STRESS DISTRIBUTION PLASTIC YIELDING
Regions experiencing high stress under pressure load
Flats/Slots
Pocket “Web”
Discriminator/Guide
June 3 - 7, 2019
2019 Gas-Lift Workshop

6. BURST IN PRESSURE VESSELS
Burst – Internal Pressure (P)
Thick Cylinder (OD/t ≤ 20)
Thick Cylinder (OD/t > 20)
June 3 - 7, 2019
2019 Gas-Lift Workshop

7. COLLAPSE IN PRESSURE VESSELS
Collapse – External Pressure (P)
Thick Cylinder (OD/t ≤ 20)
Thick Cylinder (OD/t > 20)
Stress distribution from uniform External Pressure load
YIELD STRESS  YIELD PRESSURE
June 3 - 7, 2019
2019 Gas-Lift Workshop

8. UNIFORM VS NON-UNIFORM GEOMETRY
Milled Flat
Stress distribution changes with external / internal features – Stress Concentration
June 3 - 7, 2019
2019 Gas-Lift Workshop

9. UNDER-ESTIMATION OF STRESSES FROM ASSUMPTIONS
Reversal in Stress distribution R1 R2 t Ri
At the Milled Flat, assuming an O.D of (R1 – t) = R2 and calculating stresses will be an under-estimation. Calculated safety factor will be higher than actual.

10. NEED FOR FINITE ELEMENT MODELING
Regions experiencing high stress under pressure load
STRESS CONCENTRATION
PLASTIC YIELDING
Flats/Slots
Pocket “Web”
Discriminator/Guide
June 3 - 7, 2019
2019 Gas-Lift Workshop

11. Design Verification - Old vs New Ways
Test multiple prototypes to determine safe operating pressure
Longer design lead time
Less control over material yield strength
Cost and resources
Finite Element Modeling
Ability to identify regions of interest (high stress/high yield) that hand calculations cannot
A good starting point for validation testing
Improved computing power
June 3 - 7, 2019
2019 Gas-Lift Workshop

12. 3) STRAIN GAUGE TESTING TO DETERMINE DESIGN / YIELD ACCEPTANCE CRITERIA
Strain gauge rosettes installed on regions of interest identified from FEA to record strains at test pressure.
Based on correlation between recorded strain and results of the Finite Element Model, Design Acceptance Criteria (DAC) for the observed strains was derived.
June 3 - 7, 2019
2019 Gas-Lift Workshop

13. 4) GAS LIFT SYSTEMS FOR DEEPWATER
STUDY CASE: 5-1/2” GLM RUN IN A 9-5/8” CASING
EXISTING TECHNOLOGY
INTERNAL PRESSURE (PSI) – 8,000 PSI [80]
EXTERNAL PRESSURE (PSI) – 7,000 PSI [80]
X 2.5
DEEPWATER APPLICATION
INTERNAL PRESSURE (PSI) – 20,000 PSI [XXX]
EXTERNAL PRESSURE (PSI) – 18,000 PSI[XXX]
June 3 - 7, 2019
2019 Gas-Lift Workshop

14. GAS LIFT SYSTEMS FOR DEEPWATER
Finite Element modeling at various loading conditions and determine safe operating envelope based on already derived DAC.
Identify and Analyze critical sections of interest for plastic strains and stress.
A-A
B-B
F-F
D-D
E-E
June 3 - 7, 2019
C-C
2019 Gas-Lift Workshop

15. ITERATIVE DESIGN IMPROVEMENT
DESIGN ITERATION 0
DESIGN ITERATION 1
“Achilles’ Heel” 1
June 3 - 7, 2019
2019 Gas-Lift Workshop

16. ITERATIVE DESIGN IMPROVEMENT
DESIGN ITERATION 1
DESIGN ITERATION 2
“Achilles’ Heel” 2
June 3 - 7, 2019
2019 Gas-Lift Workshop

17. ITERATIVE DESIGN IMPROVEMENT
D-D
Identify the “Achilles’ Heel” and apply the pre-determined design acceptance criteria to limit product ratings.
Section D-D
June 3 - 7, 2019
2019 Gas-Lift Workshop

18. ITERATIVE DESIGN IMPROVEMENT XX% Improvement in Ratings
DESIGN ITERATION 2
DESIGN ITERATION 3
“Achilles’ Heel” 3
XX% Improvement in Ratings
June 3 - 7, 2019
2019 Gas-Lift Workshop

19. ITERATIVE DESIGN IMPROVEMENT
Design Iteration 0
X 1.75
1ST DESIGN ITERATION
DEEPWATER APPLICATION
X 1.40
2ND DESIGN ITERATION
DEEPWATER APPLICATION

20. IDENTIFY DESIGN FAILURE POINT
Product integrity failure point was also determined based on the iterative design improvement process in conjunction with yield acceptance criteria.
In compliance with Product Performance Limit defined by API 19G1 2nd Edition Section B.1.5 Grade V1H for HPHT GL
Plastic Strain
X.X %
Y.Y %
Safety Factor
June 3 - 7, 2019
2019 Gas-Lift Workshop

21. MATERIAL [YIELD STRENGTH IN KSI]
5) Material Selection
High Strength Material options for Deepwater to achieve higher pressure ratings
MATERIAL [YIELD STRENGTH IN KSI]
INCOLOY 925[110]
INCONEL 718[120/130]
INCOLOY 945/945X[140]
June 3 - 7, 2019
2019 Gas-Lift Workshop

22. Material Selection
Higher Product cost with high strength nickel alloys
Manufacturing operations and in-house process quality control
Machining and Assembly processes
Welding and heat treatment processes
June 3 - 7, 2019
2019 Gas-Lift Workshop

23. API 19G1 QUALIFICATION TESTING
Pressure Tests
Drift Tests
Strain Gage Correlation Test
Kickover Tool Tests
June 3 - 7, 2019
2019 Gas-Lift Workshop

24. Relation between yield stress and grain size
Material Selection
Exploring Nano Structured / Nano Grain Materials for building GLMs
Potential to achieve yield strengths of 200 to 300 KSI
Hall–Petch relationship
Relation between yield stress and grain size
σy is the yield stress
d is the average grain diameter
June 3 - 7, 2019
2019 Gas-Lift Workshop

25. Questions ???
2019 Gas-Lift Workshop
June 3 - 7, 2019

26. Copyright
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Display the presentation at the Workshop.
Place it on the web site, with access to the site to be as directed by the Workshop Steering Committee.
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Other uses of this presentation are prohibited without the expressed written permission of the company(ies) and/or author(s) who own it and the Workshop Steering Committee.
2019 Gas-Lift Workshop
June 3 - 7, 2019

27. Disclaimer
The following disclaimer shall be included as the last page of a Technical Presentation or Continuing Education Course. A similar disclaimer is included on the front page of the Gas-Lift Workshop Web Site.
The Artificial Lift Research and Development Council and its officers and trustees, and the Gas-Lift Workshop Steering Committee members, and their supporting organizations and companies (here-in- after referred to as the Sponsoring Organizations), and the author(s) of this Technical Presentation or Continuing Education Training Course and their company(ies), provide this presentation and/or training material at the Gas-Lift Workshop "as is" without any warranty of any kind, express or implied, as to the accuracy of the information or the products or services referred to by any presenter (in so far as such warranties may be excluded under any relevant law) and these members and their companies will not be liable for unlawful actions and any losses or damage that may result from use of any presentation as a consequence of any inaccuracies in, or any omission from, the information which therein may be contained.
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The Sponsoring Organizations cannot and do not warrant the accuracy of these documents beyond the source documents, although we do make every attempt to work from authoritative sources. The Sponsoring Organizations provide these presentations and/or training materials as a service. The Sponsoring Organizations make no representations or warranties, express or implied, with respect to the presentations and/or training materials, or any part thereof, including any warrantees of title, non- infringement of copyright or patent rights of others, merchantability, or fitness or suitability for any purpose.
2019 Gas-Lift Workshop
June 3 - 7, 2019