Post on 06-Feb-2018
Proppant Selection
In Unconventional
Reservoirs
Terry Palisch
Director of Petroleum Engineering
November 8, 2012
Terry Palisch
Director of Petroleum Engineering
Outline
• Introduction
– Proppants
• Proppant Selection Drivers
– Importance of Conductivity
• Field Examples
– Unconventional Reservoirs
• Summary
Two primary papers are the basis for this talk….
=> SPE 106301 & 160206
“Cracking the Code” in UCRs
• The Challenge of Tight / Unconventional Reservoirs
Extremely low permeability formations
• Key technologies driving UCR development
Drilling and Completion advancements in HZ wells
HZ Operations - Perfs, plugs, completion designs
Multistage hydraulic fracturing
Do we understand our fractures as well as we
understand our completions?
Why is this Important?
• Wellbore Specifications
– Wellhead, casing, tubing, packers, etc
– Specify grade, pressure service/rating, fluid service, etc
• Fracture Stimulation
– What are you specifying for your proppant?
• i.e. proppant type and size, testing requirements, etc.
Hydrocarbons
Frac
Wellbore Sales Meter
The Proppant Conductivity Pyramid
Medium strength
Irregular size and shape Tier 2 - Medium Conductivity
Resin Coated Sand
Low strength
Irregular size and shape
Naturally Occurring Product
Tier 3 - Low Conductivity
Sand
Tier 1 - High Conductivity
Ceramic
High strength (minimizes crush)
Uniform size and shape (maximizes frac porosity and permeability)
Thermal resistant (durable, minimizes degradation)
Engineered, Manufactured Product
Highest Conductivity Highest Production, EUR, IRR
99% of all proppants used today fit
somewhere in this pyramid
Proppant Selection…can seem difficult
List not complete. Some names are registered trademarks, some historical
Lightweight
Ceramic Int. Density
Ceramic
High Density
Ceramic
CARBOLite
ECONOProp
HYDROProp
ValueProp
NapLite
MGLight
ForeProp
Sand
CARBOProp
ISP, InterProp
SinterLite
VersaProp
BoroProp
CARBOHSP
Sintered Bauxite
SinterBall
UltraProp
Ottawa, Jordan
Badger
Hickory, Brady
Colorado Silica
Arizona
White/Brown
“River” sand
With Resins:
PR = pre-cured CR =
curable
LC = low cost
DC = dual coat
AcFrac CR, PR, Black,
CARBOBond,
Tempered/Super TF
OptiProp, PowerProp
Super HS, Prime Plus
XRTGold
CARBOBond
Ceramax E
MagnaProp
Dynaprop
Ceramax P
HyperProp
CARBOBond
Ceramax V
Other
LiteProp 105, 125,
175
CARBOTag
CARBONRT
ScaleProp
Oxball, Oxfrac
Bauxlite
Proppant Selection Drivers in Shale Plays
• Availability
Availability Challenges
• “Bring us what you have” – Since 2004, global proppant utilization has increased 15-fold, and is
currently estimated at 60-70 billion lbs per year
– Demand has outstripped the pace of expansion in all Tiers
• Ceramic Plants, Resin Coating Plants, Sand Mines
– Driven proppant costs up
• Proppant Quality Can Suffer When Demand is High – SPE 84304, 101821, 119242
Quality Control & Assurance
Resin Coated Sand - Substrate Quality - Resin/Coating Technology
Uncoated Sand - Strength, Shape - Sieve Distribution - Influx of “River” Sand
Ceramics - Tight/Broad Sieve - Raw Material Quality - Process Controls - Shape/Strength - Supply Chain QA
High Quality LWC
Low
Quality
IDC
Low Quality
River Sand
Availability Challenges
• Challenges to Logistics / Distribution – Larger volumes per well / pad drilling
– Tremendous rig counts in a basin (200+)
• It is estimated that the Eagle Ford alone is using 10-15 billion lbs proppant annually
Proppant Selection Drivers in Shale Plays
• Availability
• Fluid system
Fluid System Impacts
• Fluid Selection
– Slickwater systems => 40/70 (& 100 Mesh)
– Crosslinked (Hybrid) Fluids => 30/50, 20/40 and larger
– Conductivity needs, rock fabric, cost, etc.
– Various proppant types and sizes necessary to tailor to each individual application (SPE 115766)
0
5
10
15
20
25
30
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00
20/40 Proppant
30/50 Proppant
40/70 Proppant
ASG, g/cc
Se
ttli
ng
Rate
High
Strength
Intermediate
Strength
Lightweight/
RCS/Sand
40/70 LWC/RCS/Sand
2.0
1.25
Proppant Selection Drivers in Shale Plays
• Availability
• Fluid system
• Conductivity requirements
Fracture Conductivity
cf = kf * wf
kf
wf
How wide is the road and
how good is the pavement?
How much Conductivity do I need?
cf = kf * wf
kf
wf
Dimensionless Fracture Conductivity (FCD) is a
measure of the contrast between the flow capacity
of the fracture and the formation
kf * wf FCD =
kform * xf
kform
xf
Common Misperceptions
Misunderstanding the need for conductivity “My reservoir has very low permeability….so I don’t
need much conductivity”
“Proppant A is ‘good enough’ at ___ conditions…….”
kf * wf
kform * xf
FCD =
However, the big issue is whether the Fracture
Conductivity is correctly estimated at realistic
(downhole) conditions.
Ports for Measuring
Differential Pressure
Temperature Port
Proppant Bed
Sandstone Cores
Flow Through
Proppant Bed
Reference: API RP 19C
• Ohio Sandstone
• 2 lb/ft2 Proppant Loading
• Stress maintained for 50 hours
• 150 or 250° F
• Extremely low water (2% KCl) velocity (2 ml/min)
How is Conductivity Measured?
ISO 13503-5 Conductivity Test
Pro’s & Con’s of Conductivity Testing
Reference: ISO 13503-5
Accounts for:
• Proppant Size
• Proppant Strength & Crush “Profile”
• “Wet” system
• Some temperature effects
• Some embedment
Does NOT Account for:
• Non-Darcy Flow
• Multiphase Flow
• Reduced Proppant Concentration
• Gel Damage
• Fines Migration/Cyclic Stress
• Others
Problem
To obtain a realistic proppant conductivity
for design, the API/ISO test results must be
reduced to account for:
1. Non-Darcy Flow
2. Multiphase Flow
3. Reduced Proppant Concentration
4. Gel Damage
5. Fines Migration / Cyclic Stress
6. Other
SPE 106301
ND Flow Through a Proppant Pack
ISOTest - 2 ml/min
100 bopd with 50% Sg
Or 120 MSCFD at 1500 psi BHFP
P/L = v / k + v2
Inertia Dominated
Multiphase Flow
• Relative permeability: Proppant saturated with liquid is less conducive to flowing gas
• Saturation changes: Liquid will tend to accumulate in the frac, occupying porosity that is now unavailable for gas flow
• Phase interaction: The fast-moving gas “wastes” energy accelerating the droplets of liquid. But the liquid often stops at each pore throat, only to be re-accelerated. Very inefficient flow regime!
Other Conductivity Reductions
• Lower Proppant Concentrations – Typically <1 lb/ft2
– Exacerbates ND/MP flow effects
• Gel Damage – Residual, Filter Cake, Tip Plugging
• Fines Migration – Fines of different proppant types
– Each proppant type handles fines differently
• Cyclic Stress – Each time the bottom hole flowing pressure
changes, the proppant pack rearranges and loses conductivity
• Durability – Fracture conductivity degrades over time
RCS
Courtesy Stim-Lab, Inc. Proppant Consortium
Sand
Ceramic
1540
5720
685
4310
225
1410
85
547
25 167 7 120
0
1000
2000
3000
4000
5000
6000
Eff
ec
tiv
e C
on
du
cti
vit
y (
md
-ft)
Lab Conditions High Velocity Multiple Fluids Less Proppant Gel Damage Fines/Cyclic
Stress
Jordan Sand
Lightweight Ceramic
Conductivity at Realistic Conditions
0.0001 D-m
0.029 D-m
Conditions: YM=5e6 psi,, 250°F, 1 lb/ft2, 6000 psi, 500 mcfd, 1000 psi bhfp, 50 ft H, 2 blpd
References: PredictK & SPE 106301
At baseline conditions, the Tier 1
proppant is 4x the Tier 3, but jumps
to over 15x at realistic conditions
99%
reduction
98%
reduction
0
20
40
60
80
100
120
140
Eff
ec
tiv
e C
on
du
cti
vit
y (
md
-ft)
Realistic Conditions
Jordan Sand
Lightweight Ceramic
Impact of Realistic Conditions
Conditions: YM=5e6 psi,, 250°F, 1 lb/ft2, 6000 psi, 500 mcfd, 1000 psi bhfp, 50 ft H, 2 blpd References: PredictK & SPE 106301
At baseline conditions the Tier 1
proppant performs 4x the Tier 3.
0
1000
2000
3000
4000
5000
6000
Co
nd
uc
tiv
ity
(m
d-f
t)
Lab Conditions
Jordan Sand
Lightweight Ceramic
At realistic conditions, the Tier 1
proppant performs 15x the Tier 3.
4x 15x
Additional Conductivity Considerations in UCRs
• Elevated Temperatures – Sand-based proppants lose conductivity at >200 F
– Ceramic proppants unaffected by temperature
– Eagle Ford, Haynesville, etc
0
0.2
0.4
0.6
0.8
1
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
150 deg F
200 degF
250 deg F
300 deg F
350 deg F
20/40 Premium White SandC
on
du
cti
vit
y C
orr
ecti
on
fro
m 1
50 d
eg
F,
facto
r
Additional Conductivity Considerations in UCRs
• Elevated Temperatures – Impact on natural proppants at >200 F
– Eagle Ford, Haynesville, etc
• Soft Formations – Increased proppant embedment
– Many shale plays
• Flow Convergence – Transverse fracs in horizontal wells
Tremendous pressure drop!
=> Higher conductivity imperative
The Reality
So in reality… The conductivity of our fractures is much lower than
we think
Most hydraulic fractures are “conductivity limited”
Modeling and field testing confirms that increasing the
fracture conductivity will increase production/EUR.
SPE 77675 & 134330
But…. Increasing conductivity typically increases the
investment
It is a Cost – Benefit decision
Proppant Selection Drivers in Shale Plays
• Availability
• Fluid system
• Conductivity requirements in these formations
• Cost vs Benefit – Economic Conductivity™
The Proppant Conductivity Pyramid
Medium strength
Irregular size and shape Tier 2 - Medium Conductivity
Resin Coated Sand
Low strength
Irregular size and shape
Naturally Occurring Product
Tier 3 - Low Conductivity
Sand
Tier 1 - High Conductivity
Ceramic
High strength (minimizes crush)
Uniform size and shape (maximizes frac porosity and permeability)
Thermal resistant (durable, minimizes degradation)
Engineered, Manufactured Product
Highest Conductivity Highest Production, EUR, IRR
Higher Conductivity = higher production
= higher investment
Proppant Selection is a Cost-Benefit decision
ECONOMIC CONDUCTIVITY PROCESS
Predict the fracture Conductivity at Realistic Conditions Some sophisticated Frac Models will do this
Run sensitivities to determine optimal Conductivity Provides the highest return on investment
Validate with field results Ensure field results support the modeling
Eagle Ford Shale Webb County operator
Evaluated Tier 1 vs Tier 3 proppants
Compared to internal wells, as well as offset operators
Proppant Selection Field Example #1
0
100
200
300
400
500
600
40/80 Tier 1 40/70 Tier 2 40/70 Tier 3
Bas
elin
e C
on
du
ctiv
ity,
mD
-ft Baseline Conductivity
Conductivity at Eagle Ford Conditions
SPE 155779
0
10
20
30
40
50
60
0
100
200
300
400
500
600
40/80 Tier 1 40/70 Tier 2 40/70 Tier 3
Re
alis
tic
Co
nd
uct
ivit
y, m
D-f
t
Bas
elin
e C
on
du
ctiv
ity,
mD
-ft
Baseline Conductivity
Realistic Conductivity
Eagle Ford Production Match/Modeling
SPE 138425
+100%
+50%
6 Month Cumulative BOE
Tier 3 Proppant Tier 1 Proppant
ECONOMIC CONDUCTIVITY™ - Eagle Ford Shale
SPE 155799
Primarily Tier 1
Primarily Tier 3
Production Impact of Conductivity
SPE 155799
Tier 1 Proppant
Tier 3 Proppant
Incremental Value - $1.5 MM
(payout in 9 months)
Well Completions Between Sand and Ceramic Proppant
Normalized to Number of Stages
Haynesville Shale Desoto/Caddo Parish by one operator
55 Wells – 20 utilized Tier 1 proppant, 35 utilized Tier 2
All drilled/completed similarly in similar time frame
Proppant Selection Field Example #2
32.15
32.20
32.25
32.30
32.35
32.40
32.45
-94.10 -94.05 -94.00 -93.95 -93.90 -93.85 -93.80 -93.75 -93.70
All Wells (at least 6 months production)Other Proppant
Premium Proppant
5 miles
32.15
32.20
32.25
32.30
32.35
32.40
32.45
-94.10 -94.05 -94.00 -93.95 -93.90 -93.85 -93.80 -93.75 -93.70
All Wells (at least 6 months production)Other Proppant
Premium Proppant
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 1,000,000 2,000,000 3,000,000 4,000,000
Cu
mu
lati
ve F
req
uen
cy
Cumulative Gas (MCF)
Cumulative Gas Production at Month 32
Tier 1
Tier 2
Actual Production after 2.5 years
Incremental 30% production
(0.5 BCF per well avg)
in ~2.5 Years
$1.8 million incremental PV
per well after 2.5 years, for a
$250k investment
Tier 1
Tier 2
$3.50/mcf
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
3,500,000
4,000,000
0 24 48 72 96 120 144 168 192 216 240
Cu
m G
as (
MC
F)
Months
Avg. Cumulative Gas Production
Cum Gas - Premium
Cum Gas - Other
Avg. Hyper Decline - Premium
Avg. Hyper Decline - Other
Decline Curve Analysis Projection
+35% (~1 BCF)
in 20 Years
Tier 1 Wells
Tier 1 Wells
Tier 2 Wells
Tier 2 Wells
(~0.5 BCF)
SPE 160206
Bakken Shale Mountrail County operator
Evaluated Tier 1 vs Tier 3 proppants
10 well internal field trial early in development program
Proppant Selection Field Example #3
Map of Trial Wells and Groupings
Offset (Sand) Wells
Ceramic Wells
1
2
3
4
5
6
7
3 milesSPE 160206
0
20000
40000
60000
80000
100000
120000
140000
160000
Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7
Cu
m P
rod
uct
ion
at
22
mo
nth
s, B
OE
(bb
l)
22 Month Cumulative Production per Well Average
Tier 1 LW Ceramic Wells
Tier 3 Offset Wells
Bakken Trial – Conductivity Impact
Tier 3 Wells
Tier 1 Wells
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
0 5 10 15 20
Cu
mu
lati
ve B
OE
per
wel
l (b
bl)
Months Produced
Average Cumulative Production
Tier 1 LW Ceramic Wells
Tier 3 Offset Sand Wells
+34%
A $300k investment in conductivity, has yielded a $1.5
million increase in value per well!
Bakken Trial – Conductivity Impact
13 well avg
10 well avg
Tier 3 Wells
Tier 1 Wells
Payout in ~3 months
CONDUCTIVITY Considerations in Various Plays
• Marcellus
– Transverse Fractures, Depth, Realistic Conductivity
• Utica
– Transverse Fractures, Depth, Oil / Multiple Fluids (similar to EF)
• Granite Wash – Transverse Fractures, Depth, High Gas Rate & Realistic
Conductivity
• Niobrara – Transverse Fractures, Oil / Multiple Fluids
• Most wells should see benefits to conductivity
– The only question is how much, and is it economic…
Key Take Away Messaging
• The HF process provides two things – reservoir contact and
conductive pathway.
– It is the critical (only) link between the reservoir and the wellbore
• Proppant is the conductivity pathway.
• Proppant Selection cannot be made based on depth, stress,
mean particle diameter or what the last engineer did.
– It must be designed specifically to the deliverability of a given well
• Hydraulic fractures are Conductivity Limited…period.
– The more you have, the more you make.
– One must estimate the conductivity of the fracture at realistic conditions
• Proppant Selection is a Cost vs Benefit decision
– You must determine the economic benefit of increasing the conductivity
via frac modeling and field validation
Summary
Availability (& cost) impacting proppant selection
Demand outstripping supply of quality proppant
Fluid selection and Conductivity should drive
proppant selection
Best completion practices require a realistic
estimate of conductivity
There is tremendous value at stake