Flow Control Division TM Automating Flow Control on Gas Lift Wells Comparison of Alternative...

Flow Control DivisionTM

Automating Flow Control on Gas Lift Wells

Comparison of Alternative Methods


South American Production Facility


Conventional Automation

Electric Actuated Choke Valve

Orifice Plate Flow Measurement

Flow Computer


Conventional System Schematic


Flow Meter


Well Optimization Curve


System Problems

At lower injection rates (below 2.5

MMSCFD) the well produced intermittent flow


Production Data with Conventional Automated System

Fluid Oil Injected GasDate Gross B/D Net B/D MMSCFD

3-Jan-01 1977 585 2.58-Jan-01 1426 422 2.521-Jan-01 1368 405 2.52-Feb-01 2198 954 319-Feb-01 2214 786 34-Mar-01 2114 834 312-Mar-01 2161 597 318-Mar-01 2113 583 326-Mar-01 2013 794 327-Mar-01 1980 781 330-Mar-01 2109 832 35-Apr-01 2185 689 38-Apr-01 2117 668 39-Apr-01 2028 640 2.823-Apr-01 2075 409 2.85-May-01 2283 810 2.8

29-May-01 2142 422 2.6Avg 2029.6 659.5 2.9


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


StarPac Integrated Control System


Installation Schematic


Fail in Place Lockup SystemActivates on loss of power or gas supply pressure


System Communication Schematic


Connecting StarPac to Bristol Babcock RTU


RTU to Radio Connection


Operator Interface


StarPac System Installation


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


Production with StarPac

Fluid Oil Injected GasDate Gross B/D Net B/D MMSCFD31-May-01 2191 701.12 2.6

6-Jun-01 2165 692.8 2.67-Jun-01 2137 683.84 2.6

15-Jun-01 1891 605.12 2.419-Jun-01 1902 608.64 2.220-Jun-01 2107 674.24 2.5

Avg 2065.5 661.0 2.5


Production Comparison(based on $25/bbl)

Differential 60% BS&W Days Profit BarrelsMMSCFD B/D MMSCFD B/D Fluid B/D Net Oil B/d $ Produced

2.6 2142 2.6 2191 49 19.6 12 5,880 2352.5 1977 2.5 2107 130 52 8 10,400 4162.5 1426 2.2 1902 476 190.4 5 23,800 9522.5 1368 2.2 1914 546 218.4 3 16,380 655

28 56,460 2258

Jan 2001 June 2001StarPacConventional System


Production Comparison


3-Jan-01 1977 585 2.58-Jan-01 1426 422 2.521-Jan-01 1368 405 2.52-Feb-01 2198 954 319-Feb-01 2214 786 34-Mar-01 2114 834 312-Mar-01 2161 597 318-Mar-01 2113 583 326-Mar-01 2013 794 327-Mar-01 1980 781 330-Mar-01 2109 832 35-Apr-01 2185 689 38-Apr-01 2117 668 39-Apr-01 2028 640 2.823-Apr-01 2075 409 2.85-May-01 2283 810 2.8

29-May-01 2142 422 2.6Avg 2029.6 659.5 2.9


31-May-01 2191 701.12 2.66-Jun-01 2165 692.8 2.67-Jun-01 2137 683.84 2.6

15-Jun-01 1891 605.12 2.419-Jun-01 1902 608.64 2.220-Jun-01 2107 674.24 2.5

Avg 2065.5 661.0 2.5


Results

Crude Production Increase = 4.3%

Gas Usage Reduction = 3.3%

System Payback = 12 days

Potential Gas Reduction = 24%– (Change avg. rate from 2.9 to 2.2)


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

Flow Control Division TM Automating Flow Control on Gas Lift Wells Comparison of Alternative...

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