This document discusses using artificial intelligence to optimize re-fracturing of shale wells. It notes that shale wells are fractured in multiple stages with multiple clusters, but not all clusters produce the same amount. Artificial intelligence can be used to identify production from each cluster and reasons for variations in order to determine which stages need re-fracturing. The document provides examples of how AI could be used to history match, calibrate, and validate production forecasts for each cluster to optimize re-fracturing and future well completions.

1. Copyright Intelligent Solutions, Inc. 2023
Shahab D. Mohaghegh
West Virginia University & Intelligent Solutions, Inc.
RE-FRAC OF SHALE WELLS
USING ARTIFICIAL INTELLIGENCE

2. Copyright Intelligent Solutions, Inc. 2023
RE-FRACTURING SHALE WELLS
• Hydraulic Fracturing in Shale Wells is the main characteristics of Oil and
Gas production from Shale Reservoir.
• Shale Wells are Hydraulic Fractured in each of the Stages.
• Each Stage includes several Clusters, and each Hydraulic Fracture in a
Stage impacts all the clusters in the Stage.

3. Copyright Intelligent Solutions, Inc. 2023
RE-FRACTURING SHALE WELLS
• The Shale Well that is used in this study
Heel Toe
28 26 24 22 20 18 16 14
27 25 23 21 19 17 15 13
12 10 8
11 9
6 4 2
7 5 3 1
4
Clusters
4
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
4
Clusters
4
Clusters
4
Clusters
4
Clusters
4
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
5
Clusters
has 28 Stages and 133 Clusters.

4. Copyright Intelligent Solutions, Inc. 2023
RE-FRACTURING SHALE WELLS
• Question:
• Do all the Clusters in each Stage make production?
• Answer:
• Most probably NO.

5. Copyright Intelligent Solutions, Inc. 2023
RE-FRACTURING SHALE WELLS
• Question:
• The Clusters in each Stage that make production, produce the same
amount of Oil/Gas?
• Answer:
• Most probably NO.

6. Copyright Intelligent Solutions, Inc. 2023
RE-FRACTURING SHALE WELLS
• Question:
• When does Re-Fracturing usually takes place?
• Answer:
• Re-Fracturing usually takes place after production from the Shale Well
reduces.

7. Copyright Intelligent Solutions, Inc. 2023
RE-FRACTURING SHALE WELLS
• Question:
• Does it matter that only some Stages to be Re-Fractured in a Shale Well?
Or Should the entire Shale Well be Re-Fractured?
• Answer:
• It would be more expensive to Re-Fractur the entire Shale Well.

8. Copyright Intelligent Solutions, Inc. 2023
RE-FRACTURING SHALE WELLS
• Question:
• How can it be identified which Stages must be Re-Fractured in order to
increase production?
• Answer:
• It must be identified the production from each Stage and each Cluster.
• Since each Cluster in the shale well makes different productions, the
reasons for the amount of production from each Stage/Cluster must be
identified.

9. Copyright Intelligent Solutions, Inc. 2023
RE-FRACTURING SHALE WELLS
• Question:
• If we do not know how much production comes from each Cluster,
would it be possible to identify what is causing the amount of
production?
• Answer:
• Absolutely, NO.
• First and foremost, continuous production (or lack of production) from
each Cluster must be identified.

10. Copyright Intelligent Solutions, Inc. 2023
RE-FRACTURING SHALE WELLS
• Question:
• What may be the reasons for the Minimization or Lack of Production
from each Stage and Cluster.?
• Answer:
• Reservoir Characteristics
• Completion Design
• Hydraulic Fracturing Implementation

11. Copyright Intelligent Solutions, Inc. 2023
RE-FRACTURING SHALE WELLS
• Question:
• What would be the best (and more realistic) way to identify:
A. The amount of production from each Stage and Cluster?
B. The reasons for the Minimization or Lack of Production from each Stage and
Cluster?
• Answer:
• Artificial Intelligence

12. Copyright Intelligent Solutions, Inc. 2023
PRODUCTION LOGGING IN SHALE WELLS
• It is a well-know fact that some Clusters in the Shale Wells do
not make any production.
• Production Logging Tool (PLT) can show the amount of
production from each of the Clusters in the Shale Wells.
• Another fact is that production from each Cluster changes as
a function of time.
Production Logging Tool (PLT)

13. Copyright Intelligent Solutions, Inc. 2023
DISTRIBUTED FIBER OPTIC SENSING
• Use of Fiber Optics in Shale Wells provide
Distributed Acoustic Sensing (DAS) and
Distributed Temperature Sensing (DTS).
• Most of current DTS interpretation
methods used in our industry are based on
visualization and assumptions.
• Without Artificial Intelligence, Fiber Optics will not provide realistic
and actually useful information in our industry.

14. Copyright Intelligent Solutions, Inc. 2023
Down Pass 1
13,589 ft MD
End @
3:42:29 pm
Start @
10:16:24 am
7,568 ft MD
Up Pass 1
End @
4:28:29 pm
11,668 ft MD
Start @
4:09:38 pm
13,627 ft MD
Start @
4:40:56 pm
11,690 ft MD
End @
6:06:09 pm
13,531 ft MD
Down Pass 2
Start @
6:18:25 pm
13,474 ft MD
End @
7:01:29 pm
7,482 ft MD
Up Pass 2
Production Logging Depths & Time
Heel Toe
28 26 24 22 20 18 16 14
27 25 23 21 19 17 15 13
12 10 8
11 9
6 4 2
7 5 3 1
Lumped Production Sum for
the first 7 Clusters
due to debris in hole.
Production Log on March 2, 2017
PLT

15. Copyright Intelligent Solutions, Inc. 2023
Heel Toe
28 26 24 22 20 18 16 14
27 25 23 21 19 17 15 13
12 10 8
11 9
6 4 2
7 5 3 1
PLT RESULTS
Stage Number
These are the Measured productions from each Stage on March 27, 2017
Measured
Production

16. Copyright Intelligent Solutions, Inc. 2023
SHALE WELLS’ PRODUCTION
• Since each Stage is producing a certain amount of Natural Gas, does this
mean that all the clusters in all the stage are producing Natural Gas?
Stage Number
Measured
Production
Stages include
4 Clusters
Stages include
5 Cluster

17. Copyright Intelligent Solutions, Inc. 2023
SHALE WELLS’ PRODUCTION
• When a Stage shows production, does this mean all clusters are
producing?
Stage
22
Stage
21
Stage
15
Stage
10
Heel Toe
28 26 24 22 20 18 16 14
27 25 23 21 19 17 15 13
12 10 8
11 9
6 4 2
7 5 3 1
Production
from each
Cluster

18. Copyright Intelligent Solutions, Inc. 2023
RE-FRAC OF SHALE WELLS
• To Re-Frac the Shale Wells in a positive fashion, it is important to know
the amount of production from each Clusters as a function of time.
• If we can identify the amount of production from each Cluster, then we
get the opportunity to:
A. Identify what is causing the (none, minimum, average, maximum) production
form each Cluster.
B. Enhance the production from each Cluster in all new wells.
C. Optimizing the Hydraulic Fracturing in Real-time .
D. Re-Fracturing the correct Stages.

19. Copyright Intelligent Solutions, Inc. 2023
RE-FRAC OF SHALE WELLS
• Engineering Application of Artificial Intelligence can provide CORRECT
PRODUCTION from EACH CLUSTER.
• USING Engineering Application of Artificial Intelligence includes:
• HISTORY MATCHING PRODUCTION FROM EACH CLUSTER,
• CALIBRATIONS (TESTING) PRODUCTION FROM SOME CLUSTERS,
• BLIND VALIDATION PRODUCTION FROM SOME CLUSTERS.

20. Copyright Intelligent Solutions, Inc. 2023
HISTORY MATCHING PRODUCTION FOR EACH CLUSTER

21. Copyright Intelligent Solutions, Inc. 2023
CALIBRATION (TESTING) PRODUCTION FOR EACH CLUSTER

22. Copyright Intelligent Solutions, Inc. 2023
BLIND VALIDATION (FORECAST) PRODUCTION FOR EACH
CLUSTER

23. Copyright Intelligent Solutions, Inc. 2023
Toe
Heel 28 27 26 25 24 23 14
22 21 20 19 18 17 16 15 13 12 11 10 9 8 7 6 5 4 3 2 1
Clusters used for AI model Development (Training, Calibrations, Validation)
Clusters that were not measured separately, used as Blind Validation
Clusters used as Blind Validation
Total Number of Stages = 28
Total Number of Clusters = 133
Clusters Used for Development : 121 Clusters
Blind Validation = 12 Clusters
Clusters Used for Development : 121 Clusters
Training = 97 Clusters
Calibration = 12 Clusters
Validation = 12 Clusters
AI-BASED PRODUCTION ALLOCATION FOR EACH CLUSTER
Average Error = 3.2% Average Error = 0.8%

24. Copyright Intelligent Solutions, Inc. 2023
Toe
Heel 28 27 26 25 24 23 14
22 21 20 19 18 17 16 15 13 12 11 10 9 8 7 6 5 4 3 2 1
Clusters used for AI model Development (Training, Calibrations, Validation)
Clusters that were not measured separately, used as Blind Validation
Clusters used as Blind Validation
Total Number of Stages = 28
Total Number of Clusters = 133
Clusters Used for Development : 122 Clusters
Blind Validation = 11 Clusters
Clusters Used for Development : 122 Clusters
Training = 98 Clusters
Calibration = 12 Clusters
Validation = 12 Clusters
AI-BASED PRODUCTION ALLOCATION FOR EACH CLUSTER
Average Error = 0.9%
Average Error = 0.4%

25. Copyright Intelligent Solutions, Inc. 2023
THANK YOU

26. Copyright Intelligent Solutions, Inc. 2023
CONVENTIONAL SOLUTIONS FOR
UNCONVENTIONAL FORMATIONS
Using Rate Transient Analysis (RTA) for Shale

27. Copyright Intelligent Solutions, Inc. 2023
PRODUCTION FROM SHALE WELLS
• What do we need to know in order to be able to optimize Oil/Gas
production from Shale Wells?
• Shale Wells are hydraulicly fractured in multiple Stages
• Each Stage has multiple Clusters
• Different amount of Oil/Gas is produced from each cluster

28. Copyright Intelligent Solutions, Inc. 2023
PRODUCTION FROM SHALE WELLS
• Let’s assume 50% of the Clusters are not producing.
• Where are they?

29. Copyright Intelligent Solutions, Inc. 2023
CONVENTIONAL SOLUTIONS FOR
UNCONVENTIONAL FORMATIONS
• Rate Transient Analysis (RTA) is a quick reservoir modeling solution
that has been originally developed and positively used on
conventional plays for decades.
• Currently, many operators across the regions use RTA.
• Using RTA is Simple.
• Its application includes history matching the production from the
Shale wells in order to forecast production.

30. Copyright Intelligent Solutions, Inc. 2023
CONVENTIONAL SOLUTIONS FOR
UNCONVENTIONAL FORMATIONS
• RTA is defined:
• Rate-transient analysis (RTA) is a technique used to quantitatively analyze
production data from wells drilled into unconventional reservoirs to extract
reservoir (e.g. permeability, hydrocarbons-in-place) and hydraulic fracture
(conductivity, fracture length) properties.
• Main note of this part of presentation:
• Given the complexity of the hydrocarbon production from shale wells RTA
does not provide any useful information.

31. Copyright Intelligent Solutions, Inc. 2023
CONVENTIONAL SOLUTIONS FOR
UNCONVENTIONAL FORMATIONS
• RTA’s application on oil and gas production from Shale wells has
absolutely nothing to do with Fact and Reality.
• Using RTA for Shale wells, anyone can produce any solutions that they
intend.
• RTA history matching and solution has nothing to do with Completion
Design and Hydraulic Fracturing Implementations that create
production from shale wells.

32. Copyright Intelligent Solutions, Inc. 2023
CONVENTIONAL SOLUTIONS FOR
UNCONVENTIONAL FORMATIONS
• The most complex characteristics of the Shale formations as an
unconventional reservoir is Natural Fracture Networks.
• Hydrocarbon Production from Shale wells are impacted by:
• Extensive lateral length.
• Large number of stages and clusters that are hydraulically fractured.
• Implementation of Hydraulic Fractures
• Heterogeneous reservoir characteristics throughout the horizonal well.
• Operational conditions from the surface
• If all these information (not only part of them) are not used to model,
then it cannot be REAL.

33. Copyright Intelligent Solutions, Inc. 2023
CONVENTIONAL SOLUTIONS FOR
UNCONVENTIONAL FORMATIONS
• Not using the actual characteristics of hydrocarbon Production from
Shale Wells and using conventional modeling of production from
Shale Wells, makes it extremely difficult to be realistic about
Hydrocarbon Production and fluid flow behavior along Shale wells.
• Artificial Intelligence provide a NEW and REALISTIC solution through
Shale Analytics
• Shale Analytics incorporates ALL the actual field measurements to
model, predict, and optimize Production from Shale Wells.

34. Copyright Intelligent Solutions, Inc. 2023
WHY RTA IS NOT REALISTIC
FOR SHALE WELLS?

35. Copyright Intelligent Solutions, Inc. 2023
WHY RTA IS NOT REALISTIC FOR SHALE
WELLS?
• RTA is not realistic for Shale, because engineers will be using a small part
of actual data provided from a Shale Well and they can come up with
COMPLETELY different solutions:
A. Production from this well is the BEST
B. Production from this well is the WORST
• It all has to do with the result that YOU LIKE (or Intend) to achieve,
NOT the results that is only about the Fact and Reality (actual Measured
Data) from the given Shale well.

36. Copyright Intelligent Solutions, Inc. 2023
WHY RTA IS NOT REALISTIC FOR SHALE
WELLS?
• Let’s see an EXAMPLE • From SPE Data Repository
• Data collected from industry partners to
make available use for training ,research,
publishing and development.
• Data submitted from various operators
across the country consisting of all
necessary information for RTA model of
different basins.

37. Copyright Intelligent Solutions, Inc. 2023
PRODUCTION FROM SHALE WELLS
• QUESTION: What would be the differences if a certain percent of
Clusters in a Shale well are not producing? Such as
20% or 40% or 60% or 80%

38. Copyright Intelligent Solutions, Inc. 2023
Production Efficiency
20%
Production Efficiency
40%
Production Efficiency
60%
Production Efficiency
80%
Production Efficiency
20%
Fracture Half Length
390
Fracture Conductivity
185
Number of Fractures
37
SRV Permeability
330
Production Efficiency
40%
Fracture Half Length
420
Fracture Conductivity
175
Number of Fractures
74
SRV Permeability
83
Production Efficiency
60%
Fracture Half Length
430
Fracture Conductivity
300
Number of Fractures
111
SRV Permeability
37
Production Efficiency
80%
Fracture Half Length
430
Fracture Conductivity
360
Number of Fractures
148
SRV Permeability
21
Pressure
Pressure
Pressure
Pressure
Gas
Gas
Gas
Gas
Water
Water
Water
Water