1 - Gas Lift

CE-1: Gas Lift Products and Gas Lift System Design

INSTRUCTOR : Greg Stephenson

© Schlumberger, 2001

TYPES OF ARTIFICIAL LIFT

© Schlumberger, 2001

TYPES OF GAS LIFT • CONTINUOUS FLOW GAS LIFT • INTERMITTENT GAS LIFT • CONVENTIONAL & WIRELINE RETRIEVABLE GAS LIFT EQUIPMENT

© Schlumberger, 2001

APPLICATIONS OF CONTINUOUS FLOW GAS LIFT •

TO ENABLE WELLS THAT WILL NOT FLOW NATURALLY TO PRODUCE

•

TO INCREASE PRODUCTION RATES IN FLOWING WELLS

•

TO UNLOAD A WELL THAT WILL LATER FLOW NATURALLY

•

TO REMOVE OR UNLOAD FLUID IN GAS WELLS

•

TO BACK FLOW SALT WATER DISPOSAL WELLS

•

TO LIFT AQUIFER WELLS

© Schlumberger, 2001

ADVANTAGES OF GAS LIFT • Initial downhole equipment costs lower • low operational and maintenance cost • Simplified well completions • Flexibility - can handle rates from 10 to 50,000 bpd • Can best handle sand / gas / well deviation • Intervention relatively less expensive © Schlumberger, 2001

DISADVANTAGES OF GAS LIFT

• Must have a source of gas •Imported from other fields •Produced gas - may result in start up problems

• Possible high installation cost •Top sides modifications to existing platforms •Compressor installation

• Limited by available reservoir pressure and bottom hole flowing pressure © Schlumberger, 2001

CONTINUOUS FLOW UNLOADING SEQUENCE

© Schlumberger, 2001

TO SEPARATOR/STOCK TANK

PRESSURE PSI 0

1000

2000

3000

4000

5000

6000

7000

INJECTION GAS CHOKE CLOSED

2000

TOP VALVE OPEN

4000

E UR SS

8000

RE U SS

E PR

E PR

DEPTH FTTVD

G N SI CA

THIRD VALVE OPEN

6000

NG BI TU

SECOND VALVE OPEN

10000 FOURTH VALVE OPEN

12000

14000

TUBING PRESSURE

SIBHP

CASING PRESSURE

© Schlumberger, 2001

TO SEPARATOR/STOCK TANK

PRESSURE PSI 0

1000

2000

3000

4000

5000

6000

7000

INJECTION GAS CHOKE OPEN

2000

4000

SECOND VALVE OPEN

THIRD VALVE OPEN

DEPTH FTTVD

TOP VALVE OPEN

6000

8000

10000 FOURTH VALVE OPEN

12000

14000

TUBING PRESSURE

SIBHP

CASING PRESSURE

© Schlumberger, 2001

PRESSURE PSI

TO SEPARATOR/STOCK TANK

0

1000

2000

3000

4000

5000

6000

7000

INJECTION GAS CHOKE OPEN

2000

4000

SECOND VALVE OPEN

THIRD VALVE OPEN

DEPTH FTTVD

TOP VALVE OPEN

6000

8000

10000 FOURTH VALVE OPEN

12000

14000

TUBING PRESSURE

SIBHP

CASING PRESSURE

© Schlumberger, 2001

PRESSURE PSI

TO SEPARATOR/STOCK TANK

0

1000

2000

3000

4000

5000

6000

7000

INJECTION GAS CHOKE OPEN

2000

4000

SECOND VALVE OPEN

THIRD VALVE OPEN

DEPTH FTTVD

TOP VALVE OPEN

6000

8000

10000 FOURTH VALVE OPEN

12000

14000

DRAWDOWN

TUBING PRESSURE CASING PRESSURE

FBHP

SIBHP

© Schlumberger, 2001

TO SEPARATOR/STOCK TANK

PRESSURE PSI 0

1000

2000

3000

4000

5000

6000

7000

INJECTION GAS CHOKE OPEN

2000

4000

SECOND VALVE OPEN

THIRD VALVE OPEN

DEPTH FTTVD

TOP VALVE OPEN

6000

8000

10000 FOURTH VALVE OPEN

12000

14000 DRAWDOWN

TUBING PRESSURE CASING PRESSURE

FBHP

SIBHP

© Schlumberger, 2001

PRESSURE PSI

TO SEPARATOR/STOCK TANK

0

1000

2000

3000

4000

5000

6000

7000

INJECTION GAS CHOKE OPEN

2000

4000

SECOND VALVE OPEN

THIRD VALVE OPEN

DEPTH FTTVD

TOP VALVE CLOSED

6000

8000

10000

FOURTH VALVE OPEN

12000

14000 DRAWDOWN

TUBING PRESSURE CASING PRESSURE

FBHP

SIBHP

© Schlumberger, 2001

PRESSURE PSI

TO SEPARATOR/STOCK TANK

0

1000

2000

3000

4000

5000

6000

7000

INJECTION GAS CHOKE OPEN

2000

4000

SECOND VALVE OPEN

THIRD VALVE OPEN

DEPTH FTTVD

TOP VALVE CLOSED

6000

8000

10000

FOURTH VALVE OPEN

12000

14000 DRAWDOWN

TUBING PRESSURE CASING PRESSURE

FBHP

SIBHP

© Schlumberger, 2001

PRESSURE PSI

TO SEPARATOR/STOCK TANK

0

1000

2000

3000

4000

5000

6000

7000

INJECTION GAS CHOKE OPEN

2000

4000

SECOND VALVE CLOSED

THIRD VALVE OPEN

DEPTH FTTVD

TOP VALVE CLOSED

6000

8000

10000

FOURTH VALVE OPEN

12000

14000

DRAWDOWN

TUBING PRESSURE CASING PRESSURE

FBHP

SIBHP

© Schlumberger, 2001

FIGURE 3-8: Example of the Unloading Sequence Casing Operated Valves and Choke Control of Injection Gas 2000 1800 1600

Pressure psi

1400 1200 1000 800 600 400 200 0 12:00 AM

03:00 AM

06:00 AM

PRESSURE CA SING

09:00 AM T ime

12:00 PM

03:00 PM

06:00 PM

PRESSURE TUBING

© Schlumberger, 2001

GAS LIFT WELL KICK-OFF • Unload well carefully – 50 - 100 psi (3.5 bar) per 10 min – 1 - 2 bbl per min

• • • • • • •

Maximize production choke opening Gradually increase gas injection rate Monitor well clean up and stability Get to target position Perform step rate production test Optimize gas injection rate Note - when unloading all valves open! © Schlumberger, 2001

RUNNING AND PULLING GAS LIFT VALVES KEY LEARNING OBJECTIVES UPON COMPLETION OF THIS SEGMENT, YOU SHOULD BE ABLE TO:

• • • • •

Explain the procedure for running and pulling gas lift valves from a side pocket mandrel. Describe the precautions that should be taken during running and pulling operations. Explain the operation of the OK series kickover tool. Explain the operation of the BK-1 latch. List and describe the different latch profiles available and explain the importance of latch / pocket compatability.

© Schlumberger, 2001

GAS LIFT VALVE CHANGEOUTS! • • • • • • • •

Methodical Equalise pressure Valve catcher Latches Running / pulling tools Pressure tests Experience Risk © Schlumberger, 2001

© Schlumberger, 2001

© Schlumberger, 2001

GAS LIFT VALVE LATCHES KEY LEARNING OBJECTIVES UPON COMPLETION OF THIS SEGMENT, YOU SHOULD BE ABLE TO:

• • •

Understand the purpose of a gas lift valve latch. Identify key latch components. Explain the operation of a latch.

© Schlumberger, 2001

GAS LIFT MANDRELS

SIDE POCKET MANDRELS

CONVENTIONAL MANDREL

© Schlumberger, 2001

5 1/2” MMRG-4, 1 1/2” POCKET ROUND MANDREL DESIGN Orienting Sleeve

CAMCO Tool Discriminator

‘G’ Latch Lug

Polished Seal Bore

ENGINEERING DATA PART NUMBER SIZE MAX O.D. MIN I.D. DRIFT I.D. THREAD TEST PRESSURE INTERNAL TEST PRESSURE EXTERNAL LATCH TYPE KICKOVER TOOL RUNNING TOOL PULLING TOOL MATERIAL TENSILE STRENGTH (EOEC)

05712-000-00001 5 1/2” 7.982” 4.756” 4.653” 17 LB/FT MANN BDS B x P 7740 PSI 6280 PSI RK, RK-1, RKP, RK-SP OM-1, OM-1M, OM-1S RK-1 15079 1 5/8” JDS 15155 410 S.S., 13 CR 22 HRC MAX 490,000 LBS

CAMCO 1996

© Schlumberger, 2001

GAS LIFT MANDREL NOMENCLATURE BASIC DESIGN FEATURES KB M M M G R T A U E EC W

1ST IDENTIFIER 1ST IDENTIFIER 2ND IDENTIFIER 3RD IDENTIFIER

1" POCKET 1-1/2" POCKET OVAL BODY PIPE MACHINED POCKET W/TOOL DISCRIMINATOR TOOL DISCRIMNINATOR AND ORIENTING SLEEVE CAMCO DESIGN - ROUND BODY PIPE TRUGUIDE DESIGN - ROUND BODY PIPE A POCKET PROFILE REDUCED O.D. AND I.D. STANDARD POCKET PORTING - BOTTOM EXHAUST POCKET PORTED TO TUBING - BOTTOM EXHAUST WATERFLOOD BASIC DESIGN VARIATIONS

2 3 4 5 7 8 9 10 LT LTS V

SLIGHTLY REDUCED MAJOR O.D. SPECIAL THREADING CONSIDERATIONS THREAD RECUTS EXTERNAL GUARD DEVICES SPECIAL INTERNAL MODIFICATIONS SPECIAL POCKET MODIFICATION BOTTOM LATCH ONLY PLUGGABLE OR NO PORTS SIDEPIPE POCKET PORTING SIDELUG TO ACCEPT INJECTION TUBE MULTIPLE POCKET

© Schlumberger, 2001

GAS LIFT VALVE MECHANICS

© Schlumberger, 2001

GAS LIFT VALVE MECHANICS 3 basic types of gas lift valve, each available in 1” & 1-1/2” sizes:

Dummy valves

Orifice valves • Square edged • Venturi (nova)

Unloading valves • Injection pressure (casing) operated valves • production pressure (fluid) operated valves • Throttling/proportional response valves

© Schlumberger, 2001

UNLOADING GAS LIFT VALVE • Normally required during unloading phase only • Open only when annulus and tubing pressures are high enough to overcome valve set pressure • Valve closes after transfer to next station • May be spring or nitrogen charged

© Schlumberger, 2001

Diaphragm/ Atmospheric Bellows Spring

Stem

Upstream/ Casing

Stem Tip Upstream

Downstream Port Downstream/Tubing

Pressure Regulator

Spring Operated Gas Lift Valve © Schlumberger, 2001

VALVE OPENING & CLOSING PRESSURES F=PXA

Pd

WHEN THE VALVE IS CLOSED TO OPEN IT….. 1 Pd x Ab= Pc (Ab - Ap) + Pt Ap

Pd 2

Pc 1

Pc

WHEN THE VALVE IS OPEN TO CLOSE IT….. 2 Pd x Ab = Pc (Ab)

Pt UN BALANCED VALVE © Schlumberger, 2001

VALVE OPENING & CLOSING PRESSURES CLOSING FORCE (IPO VALVE)

Fc = PbAb

OPENING FORCES (IPO VALVE)

Fo1 = Pc (Ab- Ap) Fo2 = Pt Ap

TOTAL OPENING FORCE

Fo = Pc (Ab - Ap) + Pt Ap

JUST BEFORE THE VALVE OPENS THE FORCES ARE EQUAL Pc (Ab - Ap) + Pt Ap = Pb Ab

SOLVING FOR Pc WHERE:

Pb - Pt (Ap/Ab) Pc = -------------------------1 - (Ap/Ab) Pb = Pressure in bellows Pt = Tubing pressure Pc = Casing pressure Ab = Area of bellows Ap = Area of port © Schlumberger, 2001

VALVE OPENING & CLOSING PRESSURES Pc =

Pb - Pt (Ap/Ab) ---------------------1 - (Ap/Ab)

Pc =

Pb - Pt (R) ---------------------1-R

Pb = Pc (1 - R) + Pt (R)

Where R = Ratio Ap/Ab © Schlumberger, 2001

PRODUCED FLUID

0

500

1000

1500

2000

2500

3000

3500

INJECTION GAS

2000

DEPTH FTTVD

4000

6000

8000

10000

12000

14000 DRAWDOWN

TUBING PRESSURE CASING PRESSURE

FBHP

SIBHP © Schlumberger, 2001

GAS LIFT VALVES CLOSE IN SEQUENCE 0

500

1000

1500

2000

2500

3000

3500

2000

DEPTH FTTVD

4000

6000

8000

10000

12000

14000 DRAWDOWN

TUBING PRESSURE CASING PRESSURE

FBHP

SIBHP

© Schlumberger, 2001

CASING P. TO OPEN

PRODUCED FLUID

INJECTION GAS

CASING P TO CLOSE DOME P.

AT SURFACE

1200 PSI

? PSI

TUBING P. @ DEPTH VALVE # 1

1260 PSI

? PSI

VALVE # 2

1300 PSI

? PSI

VALVE # 3

1340 PSI

? PSI

560 PSI

740 PSI

890 PSI

Pd = Pc (1(1-R) + Pt (R) NOTE : ALL VALVES 3/16” RR-20 R = 0.038 1R = 0.962 1

© Schlumberger, 2001

Pb

Pb Dome

Dome

Chevron Packing Stack

Chevron Packing Stack

Bellows

Bellows

Stem Tip (Ball) Pc

Square Edged Seat

Pc

Stem Tip (Ball) Square Edged Seat Pt Chevron Packing Stack

Pt

Check Valve

Nitrogen Charged Bellows Type Injection Pressure (Casing) Operated Gas Lift Valve

Chevron Packing Stack

Check Valve

Nitrogen Charged Bellows Type Production Pressure (Fluid) Operated Gas Lift Valve 2001 © Schlumberger,

Dome

Pb Atmospheric Bellows

Spring

Chevron Packing Stack Bellows

Chevron Packing Stack

Pc

Spring Adjustment Nut & Lock Nuts

Large T.C. Ball Tapered T.C. Seat Chevron Packing Stack

Pc

Pt

Check Valve

Nitrogen Charged Bellows Type Proportional Response Gas Lift Valve

Stem Tip (Ball) Square Edged Seat Chevron Packing Stack

Pt

Check Valve

Spring Operated Injection Pressure (Casing) Operated Gas Lift Valve

© Schlumberger, 2001

© Schlumberger, 2001

© Schlumberger, 2001

GAS LIFT VALVE FEATURES • • • • • • •

Bellows protection Max dome charge Check valve Stem travel Metallurgy Elastomers Max fluid rate

© Schlumberger, 2001

OPERATING GAS LIFT VALVE • Typically an ‘orifice’ type Gas lift valve • always open - allows gas across Passage whenever correct differential exists • Gas injection controlled by size and differential across replaceable choke • Back-check prevents reverse flow of well fluids from the production conduit

© Schlumberger, 2001

ORIFICE VALVES THERE ARE 2 TYPES OF ORIFICE VALVE: • SQUARED EDGED ORIFICE • VENTURI (NOVA)

• Valve designed for accurate gas passage prediction. • One-way check valve for tubing integrity.

© Schlumberger, 2001

NOVA VALVE

© Schlumberger, 2001