DOWNHOLE GAS LIFT AND THE FACILITY John Martinez

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 • MEASUREMENT, CONTROL, REMOTE TRANSMISSION • FLOW RATE STABILITY & GAS INJECTION RATE ASME/API GAS LIFT WORKSHOP

WHY IS GAS LIFT IMPORTANT? ASME/API GAS LIFT WORKSHOP COURTESY EXXONMOBIL – MIKE JOHNSON

WHY IS GAS LIFT IMPORTANT? ASME/API GAS LIFT WORKSHOP COURTESY SHELL – JIM HALL

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 CO 2 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 TARGET OPERATING DAILY PRESSURE, FIELD OIL FACTOR OIL Psig RATE REQUIRED & Water, % 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 2400 @ 0% @200 psig INLET OIL RATE PER WELL stb/d @50 psig INLET 2000 54 2200 49 2000 @ 25% 1050 100 1180 89 1600 @ 50% 200 302 450 134 ASME/API GAS LIFT WORKSHOP WELL COUNT

COMPRESSOR SUCTION AND DISCHARGE PRESSURE EFFECTS Discharge Pressure vs. Gas Lift Gas Requirement ASME/API GAS LIFT WORKSHOP

COMPRESSOR SUCTION AND DISCHARGE PRESSURE EFFECTS Suction Pressure vs. Gas Lift Gas Requirement ASME/API GAS LIFT WORKSHOP

COMPRESSOR SUCTION AND DISCHARGE PRESSURE EFFECTS Optimize Compression Horsepower (BHP) ASME/API GAS LIFT WORKSHOP

COMPRESSION OPTIONS OPERATING 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 ASME/API GAS LIFT WORKSHOP Dresser Industries

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 ASME/API GAS LIFT WORKSHOP Solar Gas Turbine Dresser-Clark

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 RATE GAS RATE PERMITTING SLUG FLOW, VELOCITY LESS THAN 5 FT/SEC ASME/API GAS LIFT WORKSHOP

FLOW STABILITY AND INJECTION RATE GAS RATE PROMOTES STABLE ANNULAR FLOW, VELOCITY GREATER THAN 5 FT/SEC ASME/API GAS LIFT WORKSHOP

FLOW STABILITY AND INJECTION RATE GAS 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 ASME/API GAS LIFT WORKSHOP