Transcript Automating Continuous Gas Lift

Automating Continuous Gas Lift
Injection
Gas In
Produced
Hydrocarbons
Out
Side Pocket
Mandrel with
Gas Lift Valve
Side Pocket
Mandrel with
Gas Lift Valve
Side Pocket
Mandrel with
Gas Lift Valve
Completion
Fluid
Single Production
Packer
Standard System
Configuration
Continuous G/L Application
 INCREASED PRODUCTION
 DECREASED INJECTION
Problems with Manual System
 Changing Surface Conditions
 Changing flow rates due to fixed valve position
 Can’t maintain flow at optimal position
 Surging
 Intermittent Flow
Well 1
Manual valve data Well 1
Date
BOPD
MCFDI
ICK
15-Jun-00
566
814
13
8-May-00
312
1019
13
10-Apr-00
432
1004
13
12-Oct-99
250
938
13
Well 2
Manual valve data Well 2
Date
BOPD
MCFDI
ICK
1-Sept-00
242
442
12
9-Feb-00
100
284
12
17-Nov-99
369
706
12
25-Mar-99
293
744
12
Well 3
Manual valve data Well 3
Date
BOPD
MCFDI
ICK
10-Jun-00
907
1620
15
20-Apr-00
1193
1349
15
17-Nov-99
1072
992
15
16-Oct-99
635
1471
15
Manual Valve
Gas Injection Rate
950
MCFD
850
750
650
550
450
350
0
5
10
15
20
Days
25
30
35
Manual Valve
Oil Production
800
750
700
650
BOPD
600
550
500
450
400
0
5
10
15
Days
20
25
30
Manual Valve
Tubing Pressure
200
PSI
180
160
140
120
0:00
0:30
1:00
1:30
Time
2:00
2:30
3:00
Automation Advantages
 Stabilize gas flow rates
 Stabilize casing pressure
 Stop surging
– Eliminates intermittent flow
 Use gas where most needed
 Maintain optimal flow rate
 Increase overall production
Automation Alternatives
 Conventional
Control Valve
Orifice Plate, manifold, DP cell, Transmitter
Meter run of pipe required (approx. 9’)
Controller
 StarPac integrated solution
Conventional Automation
9’
Conventional System Challenges
 Meter run of pipe required (space and weight)
 Plugging impulse lines on DP
 Slow update rate on controller (may see some
flow variation)
 Installation and tuning time
 Installation cost
 Required infrastructure
Conventional System
Installed Cost per well
 2” Control Valve = $1,500
 dp/manifold/orifice/flanges/transmitter/etc. = $3,800
Assumes compensated
Local controller/DCS/PLC/flow computer $1,200
 SI time 4 hrs at $100/hr = $400
 Wiring = $400
 Piping Modifications + Engineering = $8,000
 Labor 24 hrs at $65/hr = $1,560
 Lost Production (500 BOPD 6hrs + 100 BOPD 7 days)= $41,175
 Total Installed Cost = $58,035

StarPac Integrated Solution
StarPac Integrated Solution

Advantages
No meter run required (saves space and weight)
.25% Repeatability (30:1 rangeability)
Fast update rate (16*/sec, no flow variation)
Fully instruments line (inlet and outlet pressures, temp, flow,
dp) data easily accessible + online storage
Compensated Flow (press and temp)
Benefits realized much sooner ($$$)
– Easy installation
No sensor plugging
System diagnostics & Process diagnostics
Installed StarPac
Installed StarPac Cost per well
2” StarPac $15,000
 Labor 8hrs at $65/hr = $520
 Wiring = $200
 Piping Modifications = $0
 Lost Production = $0 - (run in bypass)
 Total Installed Cost $15,720


Note: additional savings for multiple installations (multidrop)
Space and Weight Requirements
vs Manual System for 1 well

StarPac

Weight = +20
Space addition
– L
– W
– H
0
+8”
+16”
Conventional Automation
Weight = + 120
Space addition vs manual
–
–
–
–
L
+108”
W
+12”
H
+16”
Volume 12 cu ft
Communication Options
 Local
 4-20
 Modbus
 Discrete (for interlocks)
RS-485
Serial digital
Communication (RS-485)
24 VDC
Power
Discrete
Digital
Signals
Input (2)
Output (2)
Input (1)
Secondary
4-20 mA
Signals
Output (2)
4-20 mA
Electrical
Pneumatic
Mechanical
Automation Options
All data easily accessible
 Remote System Diagnostics
 Easy tie in to Master

DCS/PLC/Laptop/SCADA/microwave

Remote software for well testing
Can design system for automatic testing

Complete gas injection data
–
–
–
–

Injection gas press/temp
Casing pressure
Mass Flow rate
Valve Position
On board data logging
Utilities

Power Requirements
24VDC @ 300 mA
Solar Cell and Batteries
In line water turbine

Actuation Options
Pneumatic
– Air regulated to 150 PSI Max
– Gas regulated to 150 PSI Max
Electro -Hydraulic
Electric
Limitations

If dp too low (less than 10% P1) need to use dp cell
If changing down hole valves, size to allow dp

Flow accuracy is 10% of reading or 2% full scale
(whichever is better)
Installed system accuracy
Cannot be used for custody transfer (if buying gas)
– May need 1 meter run and orifice for manifold gas line
Repeatability is all that’s needed for control
Required Infrastructure**
Installed System Accuracy
Conventional
VS
Integrated
Accuracy and Repeatability
“In matters of process control, precision and
repeatability are more important than accuracy.”
ISA Fundamentals of process control Theory”, 3rd
Edition, Paul W. Murrill, page 89
Well 1
No Surging!
Well 2
Well 3
Flow Control Comparison
StarPac vs Manual Gas lift
Gas Injection Rate
950
850
MCFD
750
650
550
450
Manual
350
0
5
10
15
20
Days
25
30
35
StarPac
StarPac vs Manual Gas lift
Oil Production
800
750
700
650
BOPD
600
550
500
450
400
0
5
10
15
Days
20
25
30
Manual
StarPac
StarPac vs Manual Gas lift
Tubing Pressure
200
PSI
180
160
140
120
0:00
0:30
1:00
1:30
Time
2:00
2:30
Manual
3:00
StarPac
Project Summary 3 well upgrade
 Installation time 8 hours per unit
 Installation cost $47,160 (includes lost production)
 Increased overall production by 465 BOPD
 Used 200 MCFDI less gas
 Oil increase of $11,625 / day (@$25/bbl)
 Pay-back in 4 days
 Annual Revenue Increase $4,195,965