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

1 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

GAS LIFT IN NEW FIELDS

ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for 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

2 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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

ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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

3 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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

ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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

4 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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

5 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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

6 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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

ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

DELIVERY CURVE PRODUCTION RATE VS INJECTION GAS

7 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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

8 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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

ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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

9 ASME/API/ISO Gas Lift Workshop – Doha 2007

John Martinez – Gas Lift for New Fields

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