downhole gas lift and the facility
DESCRIPTION
DOWNHOLE GAS LIFT AND THE FACILITY. John Martinez Production Associates ASME/API GAS LIFT WORKSHOP. DOWNHOLE GAS LIFT AND THE FACILITY. SYSTEM COMPONENTS SYSTEM BACKPRESSURE – NUMBER OF WELLS – OPERATING FACTOR POWER INPUT AND SYSTEM BACKPRESSURE COMPRESSION OPTIONS DEHYDRATION OPTIONS - PowerPoint PPT PresentationTRANSCRIPT
ASME/API GAS LIFT WORKSHOP
DOWNHOLE GAS LIFT AND THE FACILITY
John Martinez
Production Associates
ASME/API GAS LIFT WORKSHOP
ASME/API GAS LIFT WORKSHOP
DOWNHOLE GAS LIFT AND THE FACILITY
• 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
ASME/API GAS LIFT WORKSHOP
WHY IS GAS LIFT IMPORTANT?
COURTESY EXXONMOBIL – MIKE JOHNSON
ASME/API GAS LIFT WORKSHOP
WHY IS GAS LIFT IMPORTANT?
COURTESY SHELL – JIM HALL
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
ASME/API GAS LIFT WORKSHOP
SYSTEM BACKPRESSURE NUMBER OF WELLS OPERATING 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 BACKPRESSURE NUMBER OF WELLS OPERATING FACTOR
ASME/API GAS LIFT WORKSHOP
SYSTEM BACKPRESSURE NUMBER OF WELLS OPERATING FACTOR
RESERVOIR PRESSURE,
Psig
& Water, %
TARGET
FIELD OIL RATE
stb/d
OPERATING
FACTOR
DAILY
OIL
REQUIRED
stb/d
2400 @ 0% 100,000 0.93 107,530
2000 @ 25% 90,000 0.86 104,650
1600 @ 50% 50,000 0.83 60,240
ASME/API GAS LIFT WORKSHOP
SYSTEM BACKPRESSURE NUMBER OF WELLS OPERATING FACTOR
RESERVOIR
PRESSURE
Psig
& Water %
OIL RATE PER WELL
stb/d
@200 psig INLET
WELL
COUNT
@200 psig INLET
OIL RATE PER WELL
stb/d
@50 psig INLET
WELL
COUNT
@50 psig INLET
2400 @ 0% 2000 54 2200 49
2000 @ 25% 1050 100 1180 89
1600 @ 50% 200 302 450 134
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,
GR
OS
S S
TB
/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
3500P
RO
DU
CT
ION
RA
TE
, 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,
GR
OS
S S
T B
BL
/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
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
ASME/API GAS LIFT WORKSHOP
COMPRESSION OPTIONS - RECIPROCATING
• Reciprocating compression applied to smaller rates
• Good discharge pressure flexibility, 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
ASME/API GAS LIFT WORKSHOP
DEHYDRATION OPTIONS
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
DEHYDRATION OPTIONS
WATER CONTENT BASED ON PRESSURE AND TEMPERATURE IS PREDICTABLE
GPSA
ASME/API GAS LIFT WORKSHOP
DEHYDRATION OPTIONS
HYRATE CONDITIONS ARE PREDICTABLE
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
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 AND PRODUCION TESTS CAN DETECT UNDER PERFORMING WELLS DUE TO LIFT POINT SHIFT
• COMPRESSOR OUTAGE AND FREEZING
• SIMULATE VELOCITY AND FLOW PATTERN
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
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
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