GAS LIFT IN NEW FIELDS John Martinez Gas Lift for New Fields - PDF document

ASME/API/ISO Gas Lift Workshop – Doha 2007 GAS LIFT IN NEW FIELDS John Martinez – Gas Lift for New Fields ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields 1

ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields 2

ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields 3

ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields 4

ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields 5

ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields ASME/API/ISO Gas Lift Workshop – Doha 2007 DELIVERY CURVE PRODUCTION RATE VS INJECTION GAS John Martinez – Gas Lift for New Fields 6

ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields 7

ASME/API/ISO Gas Lift Workshop – Doha 2007 GAS METERS � METERS REQUIRED • 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 John Martinez – Gas Lift for New Fields ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields 8

ASME/API/ISO Gas Lift Workshop – Doha 2007 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 John Martinez – Gas Lift for New Fields 9