Environmentally Friendly Drilling Fluids
for Unconventional Shale
James Friedheim
Quan Guo
M-I SWACO
Buenos Aires, 7 al 10 de agosto de 2012
Shale Gas in Argentina
“Argentina is the country with the third
highest geological potential for these
types of hydrocarbons (shale gas), after
China and the United States”
- Annual Energy Outlook 2011
The study assessed the viability of 48 shale
gas basins in 32 countries and estimated
Argentina’s shale gas reserves at 774 trillion
cubic feet (TCF), 60 times greater than the
country’s current conventional reserves.
Furthermore, Argentina possesses almost
12% of the global shale gas resources, with
the Neuquen Basis showing greatest
potential.
Overview of Argentina Shale Gas Fields – (from Investment U article The Next
Big Shale Gas Boom by Justin Dove, Investment U Research; Friday, October 7, 2011)
All Shale Not the Same!
High Reactivity Shale
Moderate Reactivity
shale
Low Reactivity Shale
• Massive structure
• Lack of bedding planes
or evident laminations
• Soft
• Plastic
• Sticky
• CEC >20 meq/100g
• Predominance of
Smectite
• Moderate laminated
structure
• Bedding structure
• Easily broken
• Not plastic
• CEC 10-20 meq/100 g
• Presence of smectite
and Illite
approximately similar
proportion
• Strongly laminated
structure
• Fissile
• Brittle (Break along
lamination)
• Hard and firm
consolidation
• Not sticky
• CEC <10 meq/100g
• Predominance of illite
 Unconventional resource requires unconventional thinking
Traditional Fluids Selection Techniques
May Not Apply…..
 Effective and useful shale-fluids
interaction tests – Shale Hydration
Test, Dispersion Test, Slake
Durability Test, …
 These traditional shale-fluids
interaction and fluids selection
tests are not effective for gas
shale
Shale Play – Fluid Design
 Each shale play is different
and fluids should be tailored
for each formation
 Shale plays are usually less
reactive (swelling), but are
micro-fractured and can be
very easily destabilized by
fluid or filtrate
 The overburden is different
 Some High-Temperature
shale plays (such as
Haynesville) demand
temperature stability, good
rheology and densities up to
> 19 ppg
Marcellus Shale Core
Smectite
6711.05 –
6711.6 ft
4%
Illite
25%
Quartz
47%
Feldspar
10%
Pyrite
5%
Chlorite
6%
Ankerite
3%
CEC, (meq/100gr)
3
Permeability (nd)
19 @ 3000 psi
Permeability (nd)
6 @ 6000 psi
Porosity
10%
Total organic content
9%
Old Shales Still Can Be
Unstable in Freshwater
Fracture Tendency Allows
Water Access
Oil/Gas Shales Tend to be
Hard and Organically Rich
OBM/SBM Still Drilling Fluid
Predominately Used
• Advantages
–
–
–
–
Cost*
Readily available*
Good temperature stability
Provides good hole stability &
shale stability
– Tolerates contaminants well
– Low torque & drag while drilling
& running casing
• Concerns
– Cost**
– Availability**
– Downhole losses
Concerns
Environmental Acceptability

Toxic Compounds*

Slow degradation Rates*

Cuttings Disposal (except PARALAND)
Human Exposure Factors

High vapor emissions

Aromatic & Cyclic hydrocarbons in the
vapor, and consider carcinogenic*
*) diesel **)synthetics
Shale Gas Water-based Mud Design
Goal
Develop a low cost, environmentally friendly WBM
drilling fluid (fresh water) for the shale plays
•Straight-forward, simple, cost-conscious design.
high permeability
thick filter cake
•Environmentally friendly – precludes the use of
chloride-containing materials.
•Provide shale stability to low-reactivity, fissile shale
Concept
 Water invasion into the shale formations weakens the
low permeability
virtually no filter cake
wellbore – not so much a chemical process!
– Normal fluid loss additives are not able to form a filter cake and
therefore cannot stop the invasion of fluids, especially water.
Focus more on wellbore stability than shale inhibition for long
open hole section using WBM
Address issue of lubricity for both drilling and running casing
•
•
•
Physical Plugging
Blocks entry of fluid into the
formation
No decrease in stability
Inert chemistry
SMT (Shale Membrane Test)
4.
P1
Top Cap
Pressure differences
∆P(t) at top and bottom
are used to calculate
permeability properties
Epoxy
Base
P2
50 psi
2.
3.
Fluid at fixed flow rate and pressure
300 psi
1.
Typical Test Regime
Brine matches water
activity of the shale
Brine/Drilling fluid
Nanomaterial and
drilling fluid
Can be repeated
several times
Pressurized with
brine that matches
the water activity
shaleName
Paper # • Paper of
Titlethe
• Presenter
†
SMT Results
Atoka Shale
P1
P2
† ) Sensoy, T, Chenevert, M. E. and Sharma, M. “Minimizing Water Invasion in Shales Using Nanoparticles.” paper SPE 124429
presented at the 2009 SPE Annual Technical Conference and Exhibition, 4-7 October 2009, New Orleans, Louisiana.
What do we mean by Nano Particles?
Barite – 15,000 nm
WARP – 1,500 nm
Flu virus – 150 nm
Nanoparticles – 15 nm
CONFIDENTIAL INFORMATION © 2009 M-I L.L.C.
Silica Nanoparticle Screening
Design Considerations
• Cost
• Various coatings/treatments & Number of treatments
• Reactive groups
• Temperature stability
• Rheology effects
• Sizes 5-100 nm
• Compatibility with ions in a range of concentrations
5 nm
10-30 nm
Faster tests and better availability
than shale samples
40-50 nm
70-100 nm
Nanoparticle Characterization
40000x magnification, scale bar 50 nm
40000x magnification, scale bar 50 nm
• Cryo-Transmission Electron Microscopy (TEM) performed at Rice
University
• Right image is the best performing sample
• The images will be used to better understand their filtration behavior
Optimizing Nanoparticle Loading
Full mud formulation designed
for maximum efficiency
Loading reduced from 29% to
3% (10 ppb, Nanoparticle slurry)
Permeability reduction is
permanent
Strong stabilization of shale by
blocking fluid access
Step
Test Fluid
Permeability, nD
Permeability Reduction, %
1
4% NaCl Brine
0.153
-
2
WBM with 3% w/v of nanosilica
0.0042
97.2%
3
4% NaCl Brine
0.0035
97.6%
General Fluid Formulation
EMS 2520
PRODUCT
Freshwater
Duovis
EMI-690
Resinex
EMI-2545
Lime
Glydril GP100
Barite
Lube 945
UNITS Concn
Vol %
prn
ppb 0.75 - 1.5
ppb
1-3
ppb
8 - 12
Vol %
3-5
ppb
0.1 - 0.3
Vol %
2-3
ppb
prn
Vol %
0-3
Property
Period Aged
Temperature
Fann 35 viscometer data
600 rpm
300 rpm
200 rpm
100 rpm
6 rpm
3 rpm
10 s
10 min
PV
YP
Function
Base Fluid
Rheology
Fluid loss
Filtration
Shale sealing
Alkalinity
Filtration/lubricity
Density
Lubricity
Value
16
150
120
46
36
24
8
6
6
8
28
18
Duovis:
xanthan based rheology modifier which gives
us suspension properties
EMI-690
sufonated styrene-butadiene copolymer with
optimized fluid loss performance
Resinex:
Phenol formaldehyde resin used for additional
filtration control
Glydril GP 100:
blend of glycols used for shale inhibition, fluid
loss and baseline friction coefficient reduction
Lubricant:
General purpose Lubricant for WBM, usually
vegetable oil derivative
EMI-2545:
Nanosilica solution for physical shale plugging
Fracture Shale Consideration
• Formulated drilling fluid with 10ppb nanoparticles
(10% EMI-2545)
• 99% reduction in shale permeability
• Permeability reduction held after flushing with
brine (88% after 6 hours)
300
Brine before mud
250
Base mud
Fracture
Pressure (psi)
200
150
100
Base mud +
Nano particles
50
0
0
2
4
6
8
Time (hrs)
10
12
14
16
Additional Data on EMS 2520
Effect of lubricant package
seen at higher loadings
Environmental Testing
Mysid Shrimp testing both
additive (nanosilica) and Shale
Gas Drilling Fluid easily pass
LC50 protocol
Sample
Medium
Dosage
Results (ppm)
NanoSilica
Gen #7
20.0 ppb
>500,000
NanoSilica
Gen #7
10.0 ppb
> 500,000
0
SGWBS
NA
114,520
NanoSilica
SGWBS
10 ppb
113,850
Summary
Novel approach to shale stabilization specifically
focused on Unconventional Shale Plays source Rock
by physical plugging of Shale Pores utilizing
Nanoparticles:
 Provides high stability
 Especially coupled with designed fluid formulation
(EMS-2520) even for fractured shale
 Environmentally designed (freshwater (without
chlorides))
 Applicable for HT fluids
 Applicability to other type of shale
 Couple with chemical inhibition
 Robust testing protocol
 Performance additives for enhanced lubricity
Thank You
We would like to thank Dr Ji Lou for his
support and help on the SMT equipment and
work.
Questions?