Boyun Guo University of Louisiana at Lafayette

1. NORTH AMERICAN FRAC SAND EXHIBITION & CONFERENCE 2023
Selection of Fracture Proppant based on Conductivity, Size, and
Surface Wetting Property
Boyun Guo, PhD
University of Louisiana at Lafayette
February 21-22, 2023

2. Outline
• Types of Fracture Proppant
• Functions of Fracture Proppant
• Considerations in Proppant Selection
• Summary

3. Source: Guo et al. 2017, Petroleum Production Engineering (Image Courtesy of Carbo Ceramics)
Types of Fracture Proppant
Conductivity < Conductivity << Conductivity
Controllability < Controllability << Controllability
Cost < Cost << Cost

4. Functions of Fracture Proppant
1. Propping hydraulic fractures for fluid
flow to improve well productivity
Source: Guo et al. 2017, Petroleum Production Engineering

5. 2. Blocking formation sand production in frac-packing
Source: Guo et al. 2017, Petroleum Production Engineering

6. 3. Promoting oil production while
depressing water production
- oil-wet proppant
- water-wet proppant
- intermediate-wet proppant
Source: Wang 2022, Understanding the Effect of Proppant Surface Wettability on the Oil-Water Two phase-flow from Sandstone to
Hydraulic Fractures
Oil
Reservoir
Oil Channels
Fracture
Oil
Reservoir
Oil Channels
Water Channels
Water Channels
Sandstone
Proppant
Pack
Sandstone
Water Channel
Water Channel
Water
Channel
Water
Channel
Oil
Channel
Oil
Channel
Oil
Channel
Oil
Channel
Oil-
Wet
Oil-
Wet
Oil-
Wet
Oil-
Wet
Oil-
Wet
Oil-
Wet
Oil-
Wet

7. 1. Proppant-pack conductivity (md-ft)
▪ particle-size dependent
Considerations in Proppant Selection
Source: Berg,1970. Method for Determining Permeability From Reservoir Rock Properties.
P
e
D
k 385
.
1
2
50
1
.
5
8
.
80 −
= 








=
90
10
10
log
32
.
3
D
D
P
dn,50 = equivalent diameter of 50 weight percentile
dn,10 = equivalent diameter of 10 weight percentile
dn,90 = equivalent diameter of 90 weight percentile

8. ▪ stress-dependent
Source: Guo et al. 2017, Petroleum Production Engineering

9. 2. Proppant-size selection for frac-packing
- formation sand-size distribution
- permeability of invaded proppant pack
50
,
50
, )
6
~
5
( s
P d
D =

10. 5
.
6
1
p
D
d =
25
.
11
2
p
D
d =
36
.
19
3
p
D
d =
72
.
1
1
3
2
2
1
=
=
=
+
i
i
d
d
d
d
d
d
Source: Timiyan and Guo, 2021. A Mathematical Model for Estimating Fracture Permeability with Invasion Damage of
Formation Sand.

11. 0
10
20
30
40
50
60
70
80
90
100
0.001
0.01
0.1
1
Cumulative
Weight
%
Grain Diameter (inch)
Example: California Sand
d10 = 0.025 inch
d50 = 0.0117 inch
d90 = 0.003 inch

12. 057
.
3
003
.
0
025
.
0
log
32
.
3 10
0 =






=
P
md
234
)
400
,
25
*
0117
.
0
(
)
3
.
0
(
8
.
80 )
057
.
3
(
385
.
1
1
.
5
=
= −
e
k f
If all sand particles are allowed to invade into the pack of large
proppants in the fracture, assuming sand pack porosity of 0.3, fracture
permeability is predicted using the mathematical model. The sorting
term P in this case is:

13. 𝑘𝑓1 = 1,321 md 𝑘𝑓2 = 2,503 md 𝑘𝑓3= 2,575 md
Level of blocking: 1 2 3
𝑑1 = 0.0108 in. 𝑑2 = 0.00628 in. 𝑑3 = 0.00365 in.
𝐷1 = 0.065 in. 𝐷2 = 0.038 in. 𝐷3 = 0.022 in.

14. 3. Proppant-surface wetting property
q > 150o : superhydrophobic wetting
90o > q >120o : hydrophobic wetting
30o > q > 90o : normal wetting
10o > q > 30o : hydrophilic wetting
q < 10o : superhydrophilic wetting

15. (100-Y) % Oil
Y % Water
A “fractured” core
section simulates
reservoir rock near a
propped hydraulic
fracture.
A non-fractured core
section simulates
reservoir rock away
from a propped
hydraulic fracture.
Water Pump
Oil Pump
(100-X) % Oil
INFLUENT
X % Water
EFFLUENT
Water and oil are pumped
at constant flow rates to
the inlet
Water and oil flow rates at
the outlet are continuously
recorded
Propped “fracture”

16. PC-OW 40/80
PC-WW 40/80
PC-WW 20/40
CC-WW 20/40
Contact angle determination by the sessile drop method

17. (a) A water droplet on the surface of a
pack of water-wet particles
(b) A water droplet on the surface of a
pack of weakly water-wet particles
(c) An oil droplet on the surface of a
pack of oil-wet particles

18. Oil Droplets on
Proppants
PC-OW
40/80
PC-OW-2
20/40
PC-OW-1
20/40
Water Droplets
on Proppants

19. PC-OW 40/80
PC-WW 40/80 PC-WW 20/40
CC-WW 20/40

20. 2S 2S
V
V
Contact Angle Determination by the Drop Volume Method

21. Measurements of diameters of the wet areas on the surfaces of proppant packs

22. Proppant Sample PC-OW 40/80 PC-WW 20/40 PC-WW 40/80 CC-WW 20/40
Drop-Dimension Method 119.27 73.24 79.85 63.8
Sessile Drop Method 118.78 70.02 74.54 59.49
Difference 0.41% 4.59% 7.12% 7.24%
Water-Air-SS System: Error 2.1-3.0% Water-Air-Copper System: Error 3.5%

23. Summary
1. Fracture proppant should be selected based on conductivity, sand control,
wetting property, and cost.
2. Sand control should consider different levels of blocking to minimize sand
production and maximize proppant pack permeability.
3. Proppant surface wetting property can be characterized by liquid contact angle
quickly determined by the Drop Volume Method.

24. Thank You for Your Attention!
Any Questions?