TURBO GAS LIFTInnovative Hybrid Artificial Lift Method

Presenter: Kresimir Keglevickresimir.keglevic@zg.htnet.hr

Republic of Croatia

Ministry of Science and Technology

• ARTIFICAL LIFT METHOD COMBINED BY PUMP AND GASLIFT

• PUMP IS DRIVEN BY GAS TURBINE SUPPLIED BY COMPRESSED GAS FROM SURFACE

• THE GAS AFTER PASSING THROUGH TURBINE IS RE-INJECTED INTO PRODUCED FLUID

• PUMPING UNIT CAN BE ANY ROTATING PUMP SUCH AS CENTRIFUGAL, OR OTHER ROTATING PUMP

WHAT IS “TURBO GAS LIFT ”?

Unload valve

Chamber

Packer

Pump

Gas turbine

Chamber seal

Working valve

Small OD tubing

Large OD Tubing

TURBO GAS LIFTCOMPLETION

TURBO GAS LIFT OPERATION PRINCIPLES

BOTTOM

Production tubing

PACKER

A A

WORKING VALVEInside chamber

larger OD tubing

GAS TURBINE

VALVE

PUMP

APPLICATION AREA

• Mature fields completed by gas lift• Where back up is required; pump powered

by compressed gas instead ESP + gas lift• Where high pressure natural gas source is

available• Gas well de liquification• others

MATURE GAS LIFTED FIELD• DECREASED FORMATION PRESSURE• INCREASED WATER CUT

TO MAINTAIN PRODUCTION VOLUMES- INCREASED INJECTED GAS VOLUME

REQUIREMENTS- CONVERSION TO ESP or other mechanical method

0 10 20 30 40 50 60 100 2000

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

230050 70 90 110 130 150 170 1903010

P staticbeggining=230 bar

P static1=160 bar

GLR=200

70 80

gaslift valve surfaceclosing pressure=49 bar

gas injectionpressure

surface gaslift systempressure=61bar

GLR=300 GLR=100

B2

GLR=90turbolift

minimal difference betweengaslift valve surface closingpressure and gas injectionpressure=7.5 bar (distance A-B ,A1-B1iA2-B2)

B

B1

A

A1

A2

14601640

1290

A3 B31150

MATURE GAS LIFTED FIELD Pressure surplus utilisation

• Formation pressure drop pressure surplus

• Utilisation existing pressure surplus through turbine instead losing its working capability through a choke

• Lower achievable flowing bottomhole pressure due to application of turbo lift

• Brings an increase in production rate or lower abandonment pressure

IN SITU TURBO GAS LIFTCompressed gas supplied from gas cap

or gas bearing strata

BOTTOM

Production tubing

PACKER

A A

WORKING VALVEInside chamber

larger OD tubing

GAS TURBINE

VALVE

PUMP

OIL ZONE

GAS ZONE

System regulation

• Easily adjustable• Turbine power is

function of 1. gas flow rate 2. turbine’s intake-

discharge pressure difference

• Turbine power and subsequently pump head is easily regulated by working gas lift valve

Chamber

Pump

Gas turbine

Chamber seal

Working valve

Large OD Tubing

CENTRIFUGAL PUMP+GAS LIFT gradientsde

pth

(m)

Pwellhead

temperature

gradijent

Ps

temp. (°C)

pressure (bar)

P2Pi3 '" PizlazaP3 P1

Pd 'Pd '" Pd "

Pi2 Pi1

Reservoir pressure decline

PUMP INSTALATIONDEPTH

PUMP pressure gradient-without gas re-injection

PUMP pressure gradient withGas re-injection

Point of gas re injection

CURRENT STATUS• All components tested• Combined system tested at surface• Field installation planned for 2nd half 2009

Gas turbine + ESP surface test

Key benefits of Turbo Gas Lift• Increased volumetric efficiency-higher liquid

volumes• Superior reservoir drawdown-increased

production rate• Decreased gas injection requirements• Prolonged continuous gas lift• Provides backup if turbine or pump fails• Decreased abandonment pressure

THANK YOU FOR ATTENTION

Contacts: Kresimir Keglevic

kresimir.keglevic@zg.htnet.hr

info@tgl.hr