the facility and gas lift - alrdc part ii --- john...the facility and gas lift john martinez...
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ASME/API GAS LIFT WORKSHOP
THE FACILITY AND GAS LIFT
John Martinez
Production Associates
ASME/API/ISO GAS LIFT COURSES
ASME/API GAS LIFT WORKSHOP
THE FACILITY AND GAS LIFT
• SYSTEM COMPONENTS• SYSTEM BACKPRESSURE – NUMBER OF
WELLS – OPERATING FACTOR• POWER INPUT AND SYSTEM
BACKPRESSURE• COMPRESSION OPTIONS• DEHYDRATION OPTIONS• MEASUREMENT, CONTROL, REMOTE
TRANSMISSION• FLOW RATE STABILITY & GAS INJECTION
RATE
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ASME/API GAS LIFT WORKSHOP
WHY IS GAS LIFT IMPORTANT?
27% of EM gross operated oil production is gas lifted
2002 EM Gross Operated Oil Production
Electric Submersible
Pump2%
Progressive Cavity Pump
6%
Rod Pump 11%
Other21%
Other2%
NaturallyFlowing
52%
Gas Lift 27%
COURTESY EXXONMOBIL – MIKE JOHNSON
ASME/API GAS LIFT WORKSHOP
WHY IS GAS LIFT IMPORTANT?
COURTESY SHELL – JIM HALL
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ASME/API GAS LIFT WORKSHOP
FACILITY EQUIPMENT DRIVES GAS LIFT AND
IS THE LARGEST CAPITAL EXPENDITURE
• Onshore operator wanted more rig work and less wireline work
• Standby compressor added due to the remote location
ASME/API GAS LIFT WORKSHOP
FACILITY EQUIPMENT DRIVES GAS LIFT AND
IS THE LARGEST CAPITAL EXPENDITURE
• Offshore operator depends totally on wireline work
• Excellent dehydration was required because gas had CO2
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ASME/API GAS LIFT WORKSHOP
SYSTEM BACKPRESSURENUMBER OF WELLSOPERATING FACTOR
• RATE PER WELL VARIES WITH SEPARATOR PRESSURE (SYSTEM BACKPRESSURE)– EXPLORATION TEST RATES AND PVT DATA
• SIMULATE RESERVOIR BEHAVIOR
• SIMULATE WELL DELIVERY
• APPLY AN OPERATING FACTOR
• SIMULATE WELLS NEEDED BASED ON BOTH RESERVIOR AND DELIVERY PERFORMANCE
ASME/API GAS LIFT WORKSHOP
SYSTEM BACKPRESSURENUMBER OF WELLSOPERATING FACTOR
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ASME/API GAS LIFT WORKSHOP
SYSTEM BACKPRESSURENUMBER OF WELLSOPERATING FACTOR
60,2400.8350,0001600 @ 50%
104,6500.8690,0002000 @ 25%
107,5300.93100,0002400 @ 0%
DAILY
OIL
REQUIRED
stb/d
OPERATING
FACTOR
TARGET
FIELD OIL RATE
stb/d
RESERVOIR PRESSURE,
Psig
& Water, %
ASME/API GAS LIFT WORKSHOP
SYSTEM BACKPRESSURENUMBER OF WELLSOPERATING FACTOR
200
1050
2000
OIL RATE PER WELL
stb/d
@200 psig INLET
134 450 302 1600 @ 50%
89 1180 100 2000 @ 25%
49 220054 2400 @ 0%
WELL
COUNT
@50 psig INLET
OIL RATE PER WELL
stb/d
@50 psig INLET
WELL
COUNT
@200 psig INLET
RESERVOIR
PRESSURE
Psig
& Water %
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ASME/API GAS LIFT WORKSHOP
COMPRESSOR SUCTION AND DISCHARGE PRESSURE EFFECTS
Discharge Pressure vs. Gas Lift Gas Requirement
0 500 1000 1500 2000
INJECTION GAS LIQUID RATIO, SCF/STB
0
500
1000
1500
2000
2500
3000
3500
PR
OD
UC
TIO
N R
AT
E, G
RO
SS
ST
B/D
PI=10, INJ @ 7000',INJ PR = 1100 PSIGPI=10, INJ @ 6000',INJ PR = 800 PSIGPI=10, INJ @ 5000',INJ PR = 550 PSIGPI=1, INJ @ 7000',INJ PR = 900 PSIGPI=1, INJ @ 6000',INJ PR = 700 PSIGPI=1, INJ @ 5000',INJ PR = 500 PSIG
PRODUCTION VS INJ. GAS & INJ. PRESS.WELL 1 & 2: INJ. PRESS. VARIES WITH INJ. DEPTH, P SEP = 50 PSIG
ASME/API GAS LIFT WORKSHOP
COMPRESSOR SUCTION AND DISCHARGE PRESSURE EFFECTS
Suction Pressure vs. Gas Lift Gas Requirement
0 500 1000 1500 2000
INJECTION GAS LIQUID RATIO, SCF/STB
1000
1500
2000
2500
3000
3500
PR
OD
UC
TIO
N R
AT
E, G
RO
SS
ST
BB
L/D
P SEP = 20 PSIGP SEP = 50 PSIGP SEP = 100 PSIGP SEP = 150 PSIG
PRODUCTION VS INJ. GAS & SEP. PRESS.WELL 1: PI = 10 TBG = 4 1/2" FL = 3.958" & 2000 FT LONG INJ. @ 7000 FT
0 500 1000 1500 2000
INJECTION GAS LIQUID RATIO, SCF/STB
200
300
400
500
600
700
PR
OD
UC
TIO
N R
AT
E, G
RO
SS
ST
BB
L/D
P SEP = 20 PSIGP SEP = 50 PSIGP SEP = 100 PSIGP SEP = 150 PSIG
PRODUCTION VS INJ. GAS & SEP. PRESS.WELL 2: PI = 1 TBG = 2 7/8" FL = 2.9" & 2000 FT LONG INJ. @ 7000 FT
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ASME/API GAS LIFT WORKSHOP
COMPRESSOR SUCTION AND DISCHARGE PRESSURE EFFECTS
Optimize Compression Horsepower (BHP)
0 50 100 150 200
SEPARATOR PRESSURE, PSIG
0.06
0.07
0.08
0.09
0.1
0.11
0.12
0.13
0.14
BR
AK
E H
P P
ER
ST
B
WELL 1WELL 2
COMP. BHP/STB VS SEP. PRESS.WELL 1: PI = 10, RATE = 3000 STB/D, INJ P = 1100 PSIG
WELL 2: PI = 1, RATE = 500 STB/D, INJ P = 900 PSIG
ASME/API GAS LIFT WORKSHOP
COMPRESSION OPTIONSOPERATING EFFECTS
• WATER VAPOR IN THE GAS– REQUIRES MORE POWER FOR COMPRESSION
COMPARED TO SIMULATING DRY GAS– HEAT DUTY FOR COOLERS GOES UP –
EXCHANGER SIZE BASED ON DRY GAS IS TOO SMALL
• TEMPERATURE OF GAS AND AMBIENT– AVERAGE USED IN DESIGN, ACTUAL
OPERATING CAN BE SIGNIFICANTLY HIGHER– DRIVER DERATES, CANNOT SUPPY SUFFICIENT
POWER– COMPRESSOR CYLINDER (RECIP) OR IMPELLER
WHEELS (CENTRIFUGAL) CANNOT MOVE THE DESIGN RATE
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ASME/API GAS LIFT WORKSHOP
COMPRESSION OPTIONS - RECIPROCATING
• Reciprocating compression applied to smaller rates
• Good discharge pressureflexibility, limit on cylinder capacity
• Matched with gas engine or electric motor
Dresser Industries
ASME/API GAS LIFT WORKSHOP
COMPRESSION OPTIONS - CENTRIFUGAL
• Centrifugal compression applied to large rates offshore or internationally
• Large gas throughput in a small package
• Sensitive to gas composition changes
• Mated with gas turbine or electric motor
Solar Gas Turbine Dresser-Clark
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ASME/API GAS LIFT WORKSHOP
DEHYDRATIONOPTIONS
Triethylene glycol (TEG) is the common absorption dehydration method
Mole sieves adsorb water vapor onto the surface in the bead
ASME/API GAS LIFT WORKSHOP
DEHYDRATIONOPTIONS
WATERCONTENTBASED ON PRESSURE ANDTEMPERATURE ISPREDICTABLE
GPSA
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ASME/API GAS LIFT WORKSHOP
DEHYDRATIONOPTIONS
HYRATE CONDITIONS AREPREDICTABLE
GPSA
ASME/API GAS LIFT WORKSHOP
MEASUREMENT, CONTROL, REMOTE TRANSMISSION
• MEASURE INJECTION GAS LIFT GAS– SINGLE PHASE FLOW– STEADY PRESSURE (SHOULD BE)– MOST RELIABLE (COMPARED TO PRODUCTION
SEPARATOR)
• USE LOW POWER ACTUATED CHOKES USING SOLAR PANELS
• RADIO TRANSMISSION OF GAS MEASUREMENT DATA, WELLHEAD AND CASING PRESSURE AND TEMPERATURE
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ASME/API GAS LIFT WORKSHOP
MEASUREMENT, CONTROL, REMOTE TRANSMISSION
• INSTALL DOWNHOLE PRESSURE SENSORS IN NEW WELLS– MONITOR FLOWING BOTTOMHOLE PRESSURE– ADJUST GAS LIFT GAS RATE TO KEEP
MAINTAIN THE FLOWING BHP (NOT CONTINUOUSLY)
– MONITOR SUDDEN INCREASES WHICH INDICATE VALVE PROBLEM OR SHIFT IN POINT OF LEFT
• TRANSMIT DATA TO OPERATIONS CENTER, PLATFORM OR EVEN HOUSTON, FOR ANALYSIS AND ADJUSTMENT
ASME/API GAS LIFT WORKSHOP
FLOW STABILITY AND GAS INJECTION RATE
• VALIDATED SIMULATION ANDPRODUCION TESTS CAN DETECT UNDER PERFORMING WELLS DUE TO LIFT POINT SHIFT
• COMPRESSOR OUTAGE AND FREEZING
• SIMULATE VELOCITY AND FLOW PATTERN
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ASME/API GAS LIFT WORKSHOP
FLOW STABILITY AND INJECTION RATEGAS RATE PERMITTING SLUG FLOW,
VELOCITY LESS THAN 5 FT/SEC
ASME/API GAS LIFT WORKSHOP
FLOW STABILITY AND INJECTION RATEGAS RATE PROMOTES STABLE ANNULAR
FLOW, VELOCITY GREATER THAN 5 FT/SEC
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ASME/API GAS LIFT WORKSHOP
FLOW STABILITY AND INJECTION RATEGAS RATE PERMITS SLUG/CHURN FLOW,
VELOCITY ABOUT 5 FT/SEC
ASME/API GAS LIFT WORKSHOP
GAS LIFT OPTIMIZATION DEPENDENT ON WELL PERFORMANCE AND
FACILITY AVAILABILITY
• COMPRESSION AVAILABLE >99%• EFFECTIVE DEHYDRATION
– FREEZING IS A COMMON FIELD PROBLEM– 7 LB/MM (3 LB/MM IN COLD CLIMATES)
• GAS SYSTEM DESIGN– LOW SUCTION PRESSURE– HIGH DISCHARGE PRESSURE– POWER REQUIRED PER BARREL IS LESS AT
LOW SUCTION PRESSURE
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ASME/API GAS LIFT WORKSHOP
GAS LIFT OPTIMIZATION DEPENDENT ON WELL PERFORMANCE AND
FACILITY AVAILABILITY• FIELD SIMULATION FOR DEVELOPMENT
– RESERVOIR PRESSURE DECLINE AND WATER INCREASE– RATE VS INJECTION GAS DELIVERABILITY AT EACH
RESERVOIR CONDITION– WELL COUNT FOR DIFFERENT OPERATING CONDITIONS
• GAS MEASUREMENT– MAKE THE INJECTION GAS METER RELIABLE– MATE WITH LOW POWER CHOKE ACTUATOR AND REMOTE
TRANSMISSION CAPABILITY• FLOW STABILITY
– SIMULATE FLOW PATTERNS AND MATCH TO MEASURED AND OBSERVED BEHAVIOR
– ANNULAR FLOW– VELOCITY > 5 FT/SEC