GAS LIFT IN NEW FIELDS

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1 GAS LIFT IN NEW FIELDS GAS LIFT in NEW FIELDS NEW DESIGN FOR WELLS AND COMPRESSORS RESERVOIR AND PRODUCTION SIMULATION MATCHING REQUIRED PRODUCTION NODAL ANALYSIS SIMULATION USED TO SELECT INJECTION DEPTH REQUIRED TO MATCH RESERVOIR RATE INJECTION PRESSURE REQUIRED AND TOTAL GAS LIFT GAS RATE USED TO DESIGN COMPRESSION 1

2 GAS LIFT in NEW FIELDS REQUIRES UTILIZATION OF LIMITED DATA EXPLORATION/APPRAISAL WELLS TESTS FROM INITIAL DEVELOPMENT WELLS SIMULATE BEHAVIOR WITH COMPUTERS RESERVOIR ENGINEERING RES MODEL PRODUCTION ENGINEERING NODAL ANALYSIS SIMULATION IS APPROXIMATE BE CAUTIOUS EXPLORATION AND APPRASIAL WELLS PRODUCTION TEST DATA RATES OF GAS, OIL, WATER PRESSURE GRADIENTS AND PI PVT DATA FROM SAMPLES GOR, GAS SG, OIL API GRAVITY FLUID PROPERTIES CALIBRATE SIMULATION MODELS RELIABILITY INCREASES 2

3 RESERVOIR SIMULATION OR ENGINEERING ESTIMATE PRESSURE AND WATER BEHAVIOR VERSUS TIME RESERVOIR PRESSURE WATER FRACTION AT THE RES PRESS SEVERAL TIME STEPS 3 YEARS 6 YEARS 10 YEARS RESERVOIR SIMULATION FIELD PRODUCTION RATE INCLUDE OPERATING FACTOR TO ACCOUNT FOR DOWNTIME WELLS AND FACILITIES REQUIRE MAINTENANCE NUMBER OF WELLS REQUIRED AVERAGE RATE PER WELL FROM FIELD TOTAL AND NUMBER OF WELLS RESERVOIR SIMULATION RATES ARE APPROXIMATE 3

4 PRODUCTION SIMULATION NODAL ANALYSIS MODELS MATCH RESERVOIR SIMULATION RATES USE NATURAL FLOW PERIOD FOR CALIBRATION CALIBRATE MODELS EXPLORATION OR APPRAISAL WELL DATA INITIAL DEVELOPMENT WELLS FLOWING NATURALLY PRODUCTION NODAL ANALYSIS MUST MATCH RESERVOIR SIMULATION SIMULATE AT EACH RES PRESS WATER % INITIATE GAS LIFT MODELS DEPTH OF INJECTION IS A VARIABLE MATCH GAS LIFT RATE TO RESERVOIR MODEL DEEPER INJECTION POINT INCREASES RATE INJECTION PRESSURE ALSO INCREASES 4

5 INJECTION PRESSURE AND CORRESPONDING INJECTION DEPTH ARE LINKED NODAL ANALYSIS AT VARIOUS DEPTHS DEPTH OF LIFT TO OBTAIN REQUIRED RATE RESERVOIR RATE REQUIRED IS THE CRITERIA GAS GRADIENT CALCULATIONS FROM DEPTH OF INJECTION TO SURFACE OPERATING INJECTION PRESSURE KICKOFF PRESSURE MUST INCLUDE NUMBER OF UNLOADING VALVES EVALUATE KICKOFF PRESSURE VERSUS NUMBER OF UNLOADING VALVES MULTIPLE UNLOADING VALVES LOWER KICKOFF PRESURE MULTIPLE VALVES MORE WIRELINE OPERATIONS POTENTIAL LEAK POINTS SINGLE POINT UNLOADING HIGHER KICKOFF PRESSURE (NEAR RES PRESS) COMPRESSOR DISCHARGE MORE STAGES HIGH PRESSURE PIPING ELIMINATES UNLOADING VALVES AND PROBLEMS 5

6 GAS RATE FOR COMPRESSOR DESIGN INJECTION GAS RATE OBTAIN GAS INJECTION AT EACH TIME STEP OF RES PRESSURE AND WATER FRACTION INJ GAS PER WELL X NUMBER OF WELLS MAXIMUM GAS FOR COMPRESSOR DESIGN DEPENDS ON SELECTION OF GAS PER WELL DEPENDS ON NUMBER OF WELLS TO REACH FIELD TARGET RATE INJECTION PRESSURE IS PART OF DESIGN DELIVERY CURVE PRODUCTION RATE VS INJECTION GAS 6

7 GAS DEHYDRATION COOL INJECTION GAS FROM COMPRESSOR HOT GAS CONTAINS MORE WATER VAPOR TEG (TRI-ETHYLENE GLYCOL) LESS EFFECTIVE WHEN HOT CIRCULATE ADEQUATE AMOUNT OF TEG REDUCE WATER TO 7 LB/MILLION SCF OF GAS COLD AMBIENT TEMPERATURE MAY REQUIRE 3 LB/MILLION SCF OR LESS PIPING DESIGN PIG LAUNCHERS/RECEIVERS REMOVE LIQUID ACCUMULATIONS REMOVE SOLIDS (REDUCE CORROSION) SCRUBBERS OR KNOCKOUTS IN FIELD KEEP LIQUID SLUGS OUT OF CHOKES VERY IMPORTANT ON PLATFORMS BECAUSE SEAWATER TEMPERATURE CONDENSES HYDROCARBON 7

8 METERS REQUIRED GAS METERS INJECTION GAS METERING MORE ACCURATE THAN PRODUCTION METERING USE TO OPTIMIZE GAS LIFT GAS ALLOCATION METERS CONTROL FCV (FLOW CONTROL VALVE) FLOW RATE CONTROL CONNECTED TO SCADA AND COMPUTERS VALVE IS A PRESSURE REGULATOR GAS METER IS A FLOW CONTROLLER DATA GATHERING & CONTROL SENSORS AND TRANSMITTERS PRESSURE/TEMPERATURE AT WELLHEAD PRODUCTION WELLHEAD AND CASING INJECTION PRESSURE/TEMPERATURE AT MANIFOLD GAS RATE AND LINE PRESSURE DOWNHOLE MONITORS FOR PRESSURE COMMUNICATION DATA TO CONTROL ROOM DATA TRANSMISSION TO ENGINEERS IN OFFICE REAL TIME ANALYSIS AND IMPROVED TESTING 8

9 GAS LIFT IN NEW FIELDS USE EXPLORATION WELL DATA SIMULATION OF FUTURE RESERVOIR PRESSURE AND WATER FRACTION BEHAVIOR DEVELOP DATA AT DIFFERENT TIME STEPS USE NODAL ANALYSIS MODELING TO MATCH RESERVOIR SIMULATION SELECT DEPTH OF INJECTION AND INJECTION GAS RATE THAT MATCHES RESERVOIR MODEL DESIGN COMPRESSION INJECTION GAS PRESSURE REQUIRED TO ATTAIN DEPTH TOTAL GAS MAXIMUM OVER THE RANGE OF TIME STEPS USE AUTOMATED INJECTION GAS CONTROL AND SENSORS/TRANSMITTERS 9