Remote Operation of
Gas-lifted Wells
John Stewart
Shell Technology
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Smart Electronic Gas Lift
Cable-less Downhole Monitoring and
Flow Control for Remote Operation of
Gas-lifted Wells:
Gasmer Prototype
Laboratory
The Conch Works
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Downhole control of lift gas injection using Shell’s
cable-less technology
~
• Power and comms via tubing; current return via
casing (Pseudo-wire).
• Well head is isolated by means of electrical choke.
• Lift gas injection sub contains:
Electrically operated gas lift valve
Casing and tubing pressure gauge
Gas flow meter.
• Gas lift valve (SepTAR/Masterflo development):
• Unloading valves are remotely controllable
• Non-conducting centralisers
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Electrical Choke: Attenuation of
power signal;
Voltage difference across choke
drives P&C module
P&C module: electronics housing
and gauges
Electric gas lift valve: Masterflo
miniature choke
Check valve
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Valve body, including motor, gearbox and choke
Gas inlet ports
Check valve
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Electronics and
sensor module
Electric gas lift valve
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Electrical Choke
Value aspects
of
WirelessWell technology
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Value Aspects
– Remote monitoring and control.
– On-line data availability allows instant well optimisation.
– Permanent downhole p&T gauges included.
– Possibility to automate process on field-wide basis.
– Lift point no longer restricted by wireline capabilities.
– Downhole control of lift gas injection.
– Reduced lift gas surface infrastructure.
– Reduction in completion running time.
– Modular design.
– Cable-less: no cables and clamps to be installed.
– Dual Completions and Auto Gas Lift.
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OTHER APPLICATIONS
GAS LIFT FROM DUAL COMPLETIONS
Optimise and monitor both strings individually.
Status:
• Equipment design finalised.
• Construction and testing awaiting release of funds.
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OTHER APPLICATIONS
CABLE-LESS AUTO GAS LIFT
Use gas from gas cap or gas reservoir to lift oil.
• No surface gas lift facilities required.
• Significant cost savings on surface facilities.
• Full, real-time control.
• Ability to quickly respond to gas market
demands by switching from oil to gas
production.
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Gas Flow & Bottom Hole Pressure vs Valve Position
400
35
350
30
300
250
20
200
15
150
10
100
5
50
0
0
0
10
20
30
40
50
60
70
80
VALVE POSITION, % OPEN
BOTTOM HOLE PRESSURE
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GAS FLOW kSCMD
90
100
GAS FLOW
PRESSURE PSIG
25
Middle Eastern Deployment
0
-20
80
180
280
380
480
580
-100
-200
Controlled unloading
-300
and monitoring
-400
Conventional
gas lift mandrel
-500
Controlled lift gas injection and monitoring
150 m deeper than conventional.
-600
150m
-700
TVD
7” shoe
-800
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Open hole
680
780
880
Wireless Power & Comms – Smart Wells
Wellbore as coaxial cable:
Tubing is center conductor & casing is ground return.
Electrical isolation Choke and insulating centralizers provide electrical separation.
Power is picked off using magnetic chokes (impedance).
Communication signals ride on power using digital multiplexed encoding.
Power available downhole to operate sophisticated electric gas lift valve.
Future work: Auto Lift, Dual String Common Annulus Gas Lift
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