1. 2002 GAS-LIFT WORKSHOP PETROBRAS - Petróleo Brasileiro S.A. Gas-lift Automation: Pilot Project Edson Henrique Bolonhini PETROBRAS - UN-RNCE Galileu Paulo Henke Alves de Oliveira PETROBRAS - UN-BC HOUSTON - FEBRUARY, 2002

2. 2002 GAS-LIFT WORKSHOP Gas-lift automation - TARGETS GUIDELINESGUIDELINES – control Pwf (bottom hole flowing pressure) – action over Pcas (wellhead casing pressure)

3. 2002 GAS-LIFT WORKSHOP Gas-lift automation - TARGETS (cont.) OBJECTIVESOBJECTIVES minimum Pwf –to get the minimum Pwf by controlling Pcas delay time –to observe the well delay time after a change in Pcas PID –to verify the adequacy of a PID controller for Pcas globe valves –to verify the adequacy and controllability of globe valves for lift-gas injection ambient temperature –to observe the effects of ambient temperature on Pwf

4. 2002 GAS-LIFT WORKSHOP Hardware InstrumentsInstruments –bottom hole pressure transmitter –wellhead flowing pressure transmitter –gas-lift supply pressure transmitter –gas-lift rate transmitter –gas-lift control valve –ambient temperature transmitter –data acquisition and control module

5. 2002 GAS-LIFT WORKSHOP Tubing: Ø 2 3/8” Casing: Ø 5 1/2” Depth: 1500 m Gas-lift valves: Ø 1/8” 2 IPO 1 venturi Liquid flowrate: 25 m 3 /d GOR: 130 BSW: 35 % Bottom hole pressure and temperature transmitter: 1500 psi / 100 °C The well

6. 2002 GAS-LIFT WORKSHOP Instruments Radio and data acquisition and PID control Control valve globe Ø ¾”

7. 2002 GAS-LIFT WORKSHOP Monitoring Supervision and control room

8. 2002 GAS-LIFT WORKSHOP Results Data obtained from Dec/2001 until Jan/2002

9. 2002 GAS-LIFT WORKSHOP Oscillation Heading Flow regime effects on Pwf Tubing head pressure [kgf/cm 2 ] Ambient temperature [ o C] Control valve Opening [%] Gas-lift injection rate [Mm 3 /d] Casing head pressure [kgf/cm 2 ] Gas-lift injection pressure [kgf/cm 2 ] Bottom hole pressure [kgf/cm 2 ] PID controller under manual operation

10. 2002 GAS-LIFT WORKSHOP Ambient temperature effects on Pwf Tubing head pressure [kgf/cm 2 ] Ambient temperature [ o C] Control valve Opening [%] Gas-lift injection rate [Mm 3 /d] Casing head pressure [kgf/cm 2 ] Gas-lift injection pressure [kgf/cm 2 ] Bottom hole pressure [kgf/cm 2 ] PID controller under manual operation Night Day

11. 2002 GAS-LIFT WORKSHOP Tubing head pressure [kgf/cm 2 ] Ambient temperature [ o C] Control valve Opening [%] Gas-lift injection rate [Mm 3 /d] Casing head pressure [kgf/cm 2 ] Gas-lift injection pressure [kgf/cm 2 ] Bottom hole pressure [kgf/cm 2 ] Casing pressure set point [kgf/cm 2 ] PID control on casing pressure

12. 2002 GAS-LIFT WORKSHOP Automatic reactivation - Pwf > 53 kgf/cm 2 Tubing head pressure [kgf/cm 2 ] Ambient temperature [ o C] Control valve Opening [%] Gas-lift injection rate [Mm 3 /d] Casing head pressure [kgf/cm 2 ] Gas-lift injection pressure [kgf/cm 2 ] Bottom hole pressure [kgf/cm 2 ] Casing pressure set point [kgf/cm 2 ] PID action Gas compressor shutdown Gas compressor start-up Reactivation algorithm

13. 2002 GAS-LIFT WORKSHOP Tubing head pressure [kgf/cm 2 ] Ambient temperature [ o C] Control valve Opening [%] Gas-lift injection rate [Mm 3 /d] Casing head pressure [kgf/cm 2 ] Gas-lift injection pressure [kgf/cm 2 ] Bottom hole pressure [kgf/cm 2 ] PID controller under manual operation Condensate effects on Pwf Reactivation algorithm Pwf > 53 kgf/cm 2 Injecting gas through the 2nd GLV Circulating liquid through Venturi GLV Rain

14. 2002 GAS-LIFT WORKSHOP Final remarks –It is possible to control the Pwf behaviour through the proposed approach –PID controller-globe valve assembly showed to be efficient and beneficial –Ambient temperature has effect on the well behavior and it shows the importance of a dynamic injection control –The experiment allowed us to evaluate the system response with time –A global control algorithm should consider the conditioning of Pwf signal and its tendency Conclusions Conclusions

15. 2002 GAS-LIFT WORKSHOP PETROBRAS - Petróleo Brasileiro S.A. Gas-lift Automation: Pilot Project Edson Henrique Bolonhini PETROBRAS - UN-RNCE Galileu Paulo Henke Alves de Oliveira PETROBRAS - UN-BC HOUSTON - FEBRUARY, 2002