1. Automating Flow Control on Gas Lift Wells
Comparison of Alternative Methods

2. South American Production Facility

3. Conventional Automation
Electric Actuated Choke Valve
Orifice Plate Flow Measurement
Flow Computer

4. Conventional System Schematic

5. Flow Meter

6. Well Optimization Curve

7. System Problems
At lower injection rates (below 2.5 MMSCFD) the well produced intermittent flow

8. Production Data with Conventional Automated System

9. Conventional System Characteristics
Advantages
Simple Installation
Uses Existing Hardware
Inexpensive
No Gas Emitted
Operates at Last Set Point on Loss of Power
Disadvantages
Requires Piping Modifications
Slow Actuator Speed of Response
Deviations from Set Point
Actuator Moves in Discrete Increments (2% typical)
Very Small Movements Not Possible

10. StarPac Integrated Control System

11. Installation Schematic

12. Fail in Place Lockup System Activates on loss of power or gas supply pressure

13. SCADA Communication Scheme

14. System Communication Schematic

15. Connecting StarPac to Bristol Babcock RTU

16. RTU to Radio Connection

17. Operator Interface

18. StarPac System Installation

19. StarPac Characteristics
Advantages
Simple Installation
No Piping Modifications
No Deviation from Set Point
Fast Speed of Response
PID loop runs 16 times/sec
Actuator can move in small increments (.1% typical)
Simple System Integration
Operates at Last Set Point on Loss of Power
Disadvantages
Requires Regulated Gas for Supply
Gas Emitted

20. Production with StarPac

21. Production Comparison (based on $25/bbl)

22. Production Comparison

23. Results Crude Production Increase = 4.3% Gas Usage Reduction = 3.3%
System Payback = days
Potential Gas Reduction = 24%
(Change avg. rate from 2.9 to 2.2)

24. Why the Improvement? Speed of Response & Repeatability
StarPac holds closer to flow set point when system instabilities occur
Changing gas supply pressure
Changing flow line or tubing pressure
Stability becomes more critical as flow rate decreases
System is more likely to get upset/unstable at minimal flow rates
Smaller deviations can cause instability