Coiled tubing is a unique fluid and tool conveyance means used to intervene throughout the entire well lifetime. Its flexibility of use is certainly one of the largest in the oil-and-gas industry, ranging from logging to stimulation to cleanout and even drilling. However, for the longest time, it was only seen as a rudimentary fluid conveyance system, despite its capability to service any well deviation. With the development of instrumented tools for downhole point measurements and the use of fiber optics for distributed sensing, the recent advent of coiled tubing real-time monitoring has completely transformed this image. The access to live wellbore information—such as pressure, temperature, or flow—along with accurate depth control thanks to casing collar locator and gamma ray sensors have greatly enhanced fluid placement. Meanwhile, the ability to monitor the load, torque, and accelerations the bottomhole assembly is subjected to significantly improves the performance and possibility to use and manipulate downhole tools. Thanks to real-time monitoring, a whole new realm of optimization possibility was discovered. This lecture describes the various real-time measurements that are available today during coiled tubing interventions and how they can be used to provide the industry with faster, safer, and more efficient operations while maximizing return on investment. A wide range of applications and examples will be discussed. Through them, one will be able to appreciate how coiled tubing has now entered a new era where the limits of operational optimization still have not been reached.

1. Society of Petroleum Engineers
Distinguished Lecturer Program
www.spe.org/dl
Pierre Ramondenc
Coiled Tubing Real-Time Monitoring:
A New Era of Well Intervention &
Workover Optimization

2. Presentation Outline
• Background on coiled tubing
• Why the need for real-time downhole data?
• Review of available measurements
• A wealth of applications
• Summary
• Q&A
2

3. 3
Background on coiled tubing

4. What is coiled tubing?
“Coiled Tubing (CT) is any continuously-milled
tubular product manufactured in lengths that
requires spooling onto a take-up reel, during the
primary milling or manufacturing process”.
4
Operation PLUTO, 1944
www.histomil.com

5. What is coiled tubing?
• Straightened prior to being
inserted into the wellbore
• External diameter from 0.75
to 4 in.
• Reel lengths in excess of
30,000 ft available
• Steel yield strength ranging
from 55,000 to 135,000 psi
5
Present day coiled tubing string

6. A wide range of applications
• Fluid conveyance
• Tool conveyance
• Completions
6
Perforating
Matrix stimulation
Gravel pack

7. 7
Why the need for real-time
downhole data?

8. Limitations of conventional CT…
8Conventional CT: Only surface readouts
CT depth:
Spooled CT length
CT weight:
Hang off
Wellhead:
P, T, Q

9. … Prevent true optimization
• Need to increase safety
– Have the charges detonated?
– Are we getting stuck at depth?
• Need to increase treatment effectiveness
– Have we pumped fluid at the right place?
– Are we effectively actuating the sleeve?
• Need to increase efficiency
– Can we combine services in one run?
– Can we save time?
9

10. Monitoring as a first step
10
See what happens downhole
to take corrective actions
Everything starts with a
measurement!

11. Which data do we need?
11
Real-time
downhole
data
Accurate
BHA
positioning
Monitoring of
wellbore &
tool responses
Monitoring
of downhole
flow
Intervene at
the right place
Perform the right action
Watch for the
reservoir
response

12. 12
Review of available measurements

13. Available measurements
• Real-time (RT) telemetry first available with
wired coiled tubing, but
– Reach limitations (size and weight of wired cable)
– Pumping limitations (chemical compatibility)
– Maintenance issues
• Two telemetry systems developed since 2005
– Fiber optics
– Thin electrical conductor
• Compatible with logging tools and cameras 13

14. Available measurements
• Fiber optics provides distributed measurements
• Thin conductor cable provides power
14
Braided logging cable
IPTC 18294
0.125-in. tube wire
IPTC 18294
0.071-in. fiber-optics tube
Adapted from SPE 130365

15. Downhole point measurements
15
• Typical tools operational specifications
– Downhole pressure: 12,500 psi
– Downhole temperature: -13 to 350 F
– Maximum pump rate: 8 bpm
– Drop ball compatible
– Resistant to corrosive and abrasive fluids
Adapted from
SPE 179063

16. Distributed measurements
16
• Use of optical fiber as a sensor
Distributed temperature sensing
(DTS)
Distributed acoustic sensing
(DAS)
IPTC 16873
SPE 173686

17. Distributed measurements
17
• Performance of optical fiber depends on
– Glass core type
– Glass coating
– Packaging
• Can resist temperatures up to 450 F
• Resistance to acid depends on fiber type
• Mode of acquisition depends on fiber type

18. 18
A wealth of applications

19. Some basic applications
• CCL and GR for accurate depth control (SPE 106567)
• Temperature for treatment evaluation (SPE 184804)
• Pressure for: (SPE 143318, SPE 157379, IPTC 18294)
– Control of gas lifting procedure
– Tool actuation (e.g., jetting nozzles, packer setting)
– Condition assessment (under- / over-balanced)
• Load and torque for: (SPE 153956, SPE 163908)
– Sleeve actuation confirmation
– Downhole motor stall prevention 19

20. Pipe extension for gas control
20
• Precise depth control (CCL, GR)
– To adjust length of tubing tail extension to be cut
– To accurately place the hanging mechanism
SPE 179063

21. 21
Pipe extension for gas control
SPE 179063
• Control of guns hydraulic activation

22. 22
• Weight and
torque to confirm
anchoring
• Pressure to
control setting
process
Pipe extension for gas control
SPE 179063

23. 23
Pipe extension for gas control
0
2,000
4,000
6,000
Well A Well B Well C Well D
Qliquid, bpd
Before Intervention After Intervention
0
10
20
30
40
Well A Well B Well C Well D
Qgas, MMcf/D
Before Intervention After Intervention
• Faster than recompletion (1 week vs. 3 weeks)
• Producing life extended by at least 2 years
• Investment recovered in 1 month
SPE 179063

24. Matrix acidizing
24
• Flow
measurement
to control fluid
placement
X,500Y,600
IPTC 18362

25. Matrix acidizing
25
• Combined DTS and flow profiling to adjust
treatment strategy
IPTC 18362

26. Matrix acidizing
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• Point flow measurement complemented DTS
• Real-time downhole flow monitoring allowed
controlling fluid placement
• Optimized pumping strategy improved
injectivity nearly 300%
• Results saved drilling of additional injectors
IPTC 18362

27. Water shutoff
27
Real-time
detonation
confirmation
CMP 2016
• Control of fiber-optic compatible firing heads
Analysis of
reservoir
response

28. Water shutoff
28
• DTS to confirm interval opening and optimize
subsequent fluid placement strategy
Puncher holes
Next interval
Newly perforated
CMP 2016

29. Water shutoff
29
• Doubled oil production
• Controlled water production
• Minimized deferred production (live well)
• Combination of services in one run
– Perforating
– Chemical diversion
– Selective stimulation
– Nitrogen kickoff
CMP 2016

30. What can you think of?
Untapped potential
• DAS to evaluate step rate test
30

31. • Distributed strain sensing for pipe integrity
and fatigue management
• Support to fracturing operations:
– Selective activation for plug & perf
– Fracturing fluid placement optimization
– Flowback evaluation
• Fiber optics and electrical power combination
• RT automated intervention steering
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Untapped potential

32. 32
Summary

33. Summary
CT RT telemetry has opened a new
era of operational optimization
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• Measurements unlocks new efficiency gains
• Optimization occurs at different level
– Safer, faster, and more effective services
– Possibility to combine services in one single run
• Application limits still have not been reached

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www.spe.org/dl 34
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