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Gas Lift Systems
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Objectives
Identify the major components of a Gas
Lift System
Identify Gas Lift applications and
limitations
Have a basic understanding GL Systemoperating principles.
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Gas Lift
Gas lift is the second most commonly
used form of artificial lift today.
Its usage is very common offshore
because of space limitations and
subsurface safety valve requirements.
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Gas Lift
Gas injected at depth in order to lighten the
density of the liquid column
Decreases hydrostatic pressure
Injection is performed in stages from top to
bottom via gas lift valves until all liquid isremoved and well is flowing
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Gas Lift
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Gas Lift
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Gas Lift
An extension of natural flow
Simply a constant controlled injection of
high pressure gas into the tubing
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Injected
gas
Injected
gas
Continuous gas lift Intermittent gas lift
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Advantages
Takes full advantage of the gasenergy available in the reservoir
A high production volume method
Can handle sand or trash
Valves can be changed by wireline
Works with SSSV
Minimal downhole mechanical
devices
Full tubing bore capabilities
Excellent in deviated wellbores
Disadvantages
Can not pump off the well
Minimum bottom hole
production pressure increases
both with depth and volume
Source of gas supply
Gas distribution system
May require a compressor
Must treat corrosive gasses
(must be a dry gas)
Gas Lift
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Gas Lift Valves
Tubing
Tubing entryport
Valve entryports
Stem & seat
Gas chargeddome
Bellows
Ap
Pt
Pc
Ab
Pd
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Valve with spring Valve with bellows only
C
Pd
Ab
Pc
Av
Pd
Ab
D
Pc
Av
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Tubing
pressure
Latch
Packing
Casing
pressure
Packing
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1
Positioningsleeve
Locator key
Pivot lever
arm
Latch
2 3
200 lbs.
AA
A - A
4 5
0 0 0
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04
00
800
1200
1600
2000
0
1000
2000
3000
4000
5000
6000
Depth, ft
Pwf
Optimum point of injection
Casing pressure gradient
Pr
psi
Perforation
depth
Flowing gradient above point ofinjection
Static reservoir gradient
0 0 0
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04
00
800
1200
1600
2000
0
1000
2000
3000
4000
5000
6000
Depth, ft
Pwf
Optimum point of injection
Casing pressure gradient
Pr
psi
Perforation
depth
Flowing gradient above point of injection
Kick off point
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0
2000
4000
6000
8000
10000
0 400 800 1200 1600 2000 2400
Pressure
Dep
th
2530'
4000'
5100'
6000'
6600'7100'7500'
600bpd
7800'8050'8250'
Equilibrium Curve
Pwh (min)
Pinj
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Lower zone perforations
Single packer
Upper zone perforations
Dual packer
Gas lift valve and mandrels to be staggered
Injection gas
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Gas Lift
Surface equipment
Gas supply source:
gaswell
separator gas with compressor
Surface gas flow distribution & control
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Key words Lighten fluid column
extension of natural flow static gradient
flowing gradient
drawdown casing pressure gradient
optimum point of injection
kick off point
gaslift valves, wireline change out
gaslift gas source
gaslift gas distribution
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End of Session