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TURBO GAS LIFTInnovative Hybrid Artificial Lift Method
Presenter: Kresimir [email protected]
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