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• Approach to keep flowing a well• Introduction to artificial lift methods• Artificial lift systems operating envelopes
Improved HC Recovery: Agenda
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• AL is an integral part of production system• Cannot be decoupled from
– Reservoir– Other well completion equipment– Pipeline system– Topsides process plant
• Ideally model from reservoir to export pump
Approach to keep flowing a well: Getting AL in Context
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Approach to keep flowing a well: Procedure
• Stage 1: Screening study to identify optimum lift method(s)
• Stage 2: Check the fluid mechanics
• Stage 3: Detailed design
Screening study
Fluid mechanics Detailed design
Flow Assurance
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Screening Procedure• Production profile (Q, GOR, PI, Pres, WC) from simulator• Generate production profiles for competing AL methods
– Natural flow is the benchmark– Consider all methods(beware popular misconceptions!)– May require different methods as conditions change
• Develop capital and operating costs• Generate NPV for competing methods
– Establish optimum method(s)– Max NPV may not coincide with max oil production!
Approach to keep flowing a well: Stage 1
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Check the fluid mechanics• Consider all of the flow processes
– Liner– AL device– Tubing– Annulus– Unsteady state phenomena– Solids transport– 20% of problems regarded as “niche”– Need to get the physics correct!!!!!!
• Build in flexibility– May require different methods as conditions change
• Anticipated changes • Surprise changes
– Back up AL method in event of failure
Approach to keep flowing a well: Stage 2
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Detailed mechanical design• Safety• Casing scheme• Prod chemistry(scale, asphaltene, wax, hydrates, emulsion, other materials)• Impact of solids• Surface facilities(press/temp, power, capacities)• Stress analysis
Approach to keep flowing a well: Stage 3
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• Natural flow– Uses reservoir energy to transport fluids
• Artificial lift– Uses combination of reservoir energy and added energy to
• Produce dead well• Increase off-take from natural flow well
Artificial lift methods: Well flow mechanisms
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• Physical property modification– Gas lift– Injection of diluents, demulsifiers or friction reducing agent
• Pumping methods– Positive displacement pumps
• Piston pumps (rod, hydraulic)• Progressive cavity pumps (rod, DH electric motor)
– Dynamic displacement pumps• Centrifugal pumps(ESP, HSP)• Jet pumps
• Combination
Artificial lift methods: Generic classification
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• Downhole• Surface(multiphase pumps)
– Welcom system (jet pumps)– Framo (screw pump)
Artificial lift methods: Location-wise classification
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Flow Assurance: To optimize HC recovery
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Gas lift• Continuous injection• Intermittent injection
Artificial lift methods: Physical Property modification
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Velocity String
Artificial lift methods: Physical Property modification
Introduce a surfactant at bottom of tubing to induce foaming
• Relatively simple application• Can be applied to wide range of VICO completion
(monobore, Short/Long String with nipple profile, selective produce through sliding sleeve, etc)
• Liquid soap/surfactant is easy to inject across perforation
• Continuous liquid soap injection maintain the gas velocity above the critical velociy for certain periods. However, to keep the well unloaded for a longer period of time requires continuous optimization.
Cap-String Component:• ¼” Capillary String• Bulk Tank for Chemical Storage• Liquid Pump & Solar Power• Consumable Chemical Injection
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Capillary String
Artificial lift methods: Physical Property modification
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Plunger Lift
Artificial lift methods: Physical Property modification
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Artificial lift methods: Pumping methods
Positive displacement 1
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Artificial lift methods: Pumping methods
Positive displacement 2
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sensor
• Rotary system comprising:– rod string, down hole
pump & gauges, drive head, control system
• Rotor turned by:– rod string or sucker rods
(RDPCP)– downhole electric motor
(ESPCP)
• Rod string weakest point as it delivers the torque
RDPCP ESPCPPositive displacement 2
Artificial lift methods: Pumping methods
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Artificial lift methods: Pumping methods
Dynamic displacement 1
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S S D c /w jetpump
Dynamic displacement 2
Artificial lift methods: Pumping methods
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Artificial lift methods: Combination
Gas lift with auto jet pumping
• Primary lift GL, secondary JP• Without Jet pump
– Upper zone dominates– Small oil rate
• With jet pump– Upper zone pumps lower
zone– Increased oil rate– Jet pump optimisation
required• Niche application
S S D c /w J etpum p
Lower z one(S mal l P I,W C)
Upper z one(Large P I, W C)
G L V
L IFT G A S
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Artificial lift methods: Combination
Gas lift with auto jet pumping
S S D c /w J etpum p
Lower z one(S mal l P I,W C)
Upper z one(Large P I, W C)
G L V
L IFT G A S
Autojetpumping
0
50
100
150
200
0 2 4 6 8 10
Jetpump Size
Qo
Qo_upper
Qo_lower
Qo_total
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Artificial lift methods: Combination
Combination lift (Gas lift with auto jet pumping)
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Artificial lift methods: Surface
Multiphase pumpsWell Performance
0
200
400
600
800
1000
1200
1400
1600
0 50 100 150 200 250 300 350 400 450
Pmanifold(psia)
Flow
rate
(stb
/d0
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Artificial lift methods: Surface
Multiphase pumps
• Jet pumps (e.g. Welcom system)– L– G– Multiphase
• Screw pump (e.g. Framo)– L– G– Multiphase pe
troso
l
Artificial lift methods: Surface
Multiphase pumps
• Free gas detrimental to pumps– Maximum volumetric rate– Free gas decreases pump efficiency
• Example(Stag field)– Pres=1140 psia– GOR=400 scf/stb– WC=0– V/L increases rapidly as P decreases– P=1140, V/L=0.2– P=100,V/L=10
• Qo=10,000 stb/d• Qpump~110,000 rb/d !!!!
• Gas separation required
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Fluid level
In ta ke
Liquid+gas
Motor
Seal
RGS D is c ha rg e
Gas
Pump
Liquid
Gas Liquid
Separate
Reservoir Fluids
Pump
Gas Separation
Artificial lift methods: Pumping Systems
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AL operating envelopes: Energy balance
Q Pwh
Q Pwf
EnergyInput
Datum Level
Artificial LiftDevice
TVD
Wellhead
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AL operating envelopes: Relative performance
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AL operating envelopes: System efficiencies
ηQ P wh. PE wh Q Pwf. PE wf
E
Q Pwh
Q Pwf
EnergyInput
Datum Level
Artificial LiftDevice
TVD
Wellhead
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AL operating envelopes: Typical system efficiencies
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Artificial Lift Comparison
Operating Parameters
Positive displacement pumps Dynamic displacement pumpsGas lift Plunger liftRod pump PCP Hydraulic
PistonESP Hydraulic Jet
Typical Operating Depth (TVD)-ft
100-11000 2000 -4500 7500-10000 5000-10000 5000-10000 To 8000
Typical Operating Volume-BFPD
5 -1500 5- 2200 50 - 500 100 – 30000 300 – 4000 100 – 10000 1 – 5
Typical Operating Temperature-º F
100 – 350 75 - 150 100 - 250 100 – 250 100 - 250 120
Typical Wellbore Deviation-deg
0 - 20 N/A 0 - 20 0 - 20 0 - 50 N/A
Corrosion handling Good to Excellent
Fair Good Good Excellent Good to excellent
Excellent
Gas handling Fair to good Good Fair Fair Good Excellent Excellent
Solids handling Fair to good Excellent Poor Fair Good Good Poor to Fair
Fluid gravity > 8 º API < 35 º API > 8 º API > 10 º API > 8 º API > 15 º API GLR = 300 SCF/Bbl per 1000 ft of depth
Servicing Workover or pulling rig
Workover or pulling rig
Hydraulic or wireline
Workover or pulling rig
Hydraulic or wireline
Wireline or workover rig
Wellhead catcher or wireline
Prime mover Gas or electric
Gas or electric
Multi-cylinder or electric
Electric motor
Multi-cylinder or electric
Compressor Well’s natural energy
System efficiency 45% - 60% 40% - 70% 45% - 55% 35% - 60% 10% - 30% 10% - 30% N/A
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Thank Youfor assistance on artificial lift
systems, reach us:
Visit our website:http://www.petrosol.co
Any enquiry please contact us:[email protected]
