Apresenta

1
PETROBRAS - Petróleo Brasileiro S.A.
2002 GAS-LIFT WORKSHOP
Gas-lift Automation Pilot Project
HOUSTON - FEBRUARY, 2002
Edson Henrique Bolonhini PETROBRAS -
UN-RNCE Galileu Paulo Henke Alves de
Oliveira PETROBRAS - UN-BC
2
Gas-lift automation - TARGETS

• GUIDELINES
• control Pwf (bottom hole flowing pressure)
• action over Pcas (wellhead casing pressure)

3
Gas-lift automation - TARGETS (cont.)

• OBJECTIVES
• to get the minimum Pwf by controlling Pcas
• to observe the well delay time after a change in
  Pcas
• to verify the adequacy of a PID controller for
  Pcas
• to verify the adequacy and controllability of
  globe valves for lift-gas injection
• to observe the effects of ambient temperature on
  Pwf

4
Hardware

• Instruments
• 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
The well
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 m3/d GOR 130 BSW 35
Bottom hole pressure and temperature transmitter
1500 psi / 100 C
6
Instruments
Control valve globe Ø ¾
Radio and data acquisition and PID control
7
Monitoring
Supervision and control room
8
Results
Data obtained from Dec/2001 until Jan/2002
9
Flow regime effects on Pwf
Oscillation
Heading
10
Ambient temperature effects on Pwf
Night
Day
11
PID control on casing pressure
12
Automatic reactivation - Pwf gt 53 kgf/cm2
PID action
Reactivation algorithm
Gas compressor shutdown
Gas compressor start-up
13
Condensate effects on Pwf
Injecting gas through the 2nd GLV Circulating
liquid through Venturi GLV
Reactivation algorithm Pwf gt 53 kgf/cm2
Rain
14
Final remarks

• Conclusions

• 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

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