Advanced Recovery Processes for Conventional Reservoirs and Shale Tony Kovscek Energy Resources Engineering School of Earth, Energy, and Environmental Sciences
Advanced Recovery Processes for
Conventional Reservoirs and Shale
Tony Kovscek
Energy Resources Engineering
School of Earth, Energy, and Environmental
Sciences
Outline
Shale and CO2 Cooptimized EOR & Storage
CO2
zero-entry capillary pressure barrier
oil
zero capillary entry pressure barrier 0
0.1
0.2
0.3
0.4
0.5
0.6
0 2000 4000 6000 8000 10000 12000 14000 16000days
CO2 injectionSolvent InjectionWAG 0.01 PV - CO2WAG 0.01 PV - solventGAW - CO2GAW - solventWC - CO2WC - solvent
Shale EOR and CO2
CO2
zero-entry capillary pressure barrier
oil
What could we do with abundant CO2?
• enhance gas recovery
• enhance oil recovery
• replace fracturing fluids
• store CO2
https://www.acs.org/content/acs/en/pressroom/presspacs/2015/acs-presspac-november-18-2015/profit-from-co2.html
U.S. Oil Production
(million barrels per day)
2
4
6
8
10
1949
1957
1965
1973
1981
1989
1997
2005
2013
Conventional
Decline Curve
Source: U.S. Department of Energy, Energy Information Administration (EIA)
Recovery factor ~ 5%
U.S. Natural Gas Production
(billions of cubic feet per day)
Shale Gas
Non-Shale Gas
20
30
40
50
60
70
2000
2003
2006
2009
2012
Unconventional
Conventional
Recovery factor ~ 25%
Small Recovery Factors From Shale
5
! = #$ ⁄& ' − #$ ⁄) '#$&)* − #$+),--.
Storage Capacity (/) =Adsorbed Gas + Free Gas
(ф)
Aljamaan, H. C. M. Ross, and A. R. Kovscek, Society of Petroleum Engineers Journal, 22(6), 1760-1777 (2017).
6
Study Samples
Barnett 26-Ha Eagle Ford EF-4 Haynesville TWG3-2 Permian P-2
Source Sample Depth (ft) Ro TOC Clays Carbonates Quartz Feldspar Pyrite
Barnett 26-Ha 8620.1 - 11.7 25.2 10.4 45.1 5.8 1.7
Eagle Ford EF-4 11184.8 1.39 5.1 20.3 48.9 18 3.8 3.9
Haynesville TWG3-2 11134.05 1.37 1.9 22.8 49.5 16.8 6.9 2.0
Permian+ P-2 10134.25 1.28 0.5 5.5 68.8 17.5 7.3 1.0
clay—QFP—carbonate
Aljamaan, H. C. M. Ross, and A. R. Kovscek, Society of Petroleum Engineers Journal, 22(6), 1760-1777 (2017).
7
Kr vs CO2 Storage Capacity
Kr
CO2
Barnett Eagle Ford Haynesville Permian
5.6
10.2
x = 9.9
x= 12.8 17.5
11.0
14.4
7.8
Aljamaan, H. C. M. Ross, and A. R. Kovscek, Society of Petroleum Engineers Journal, 22(6), 1760-1777 (2017).
Kr CO2
• CO2 and Kr storage distribution slices aligned with
SEM mosaic
20 40 60 80 100
10
20
30
40
50
60
70
80
90
100
0
0.05
0.1
0.15
0.2
0.25
Low /High //
8
Eagle FordCT/SEM Registration
Aljamaan, H. C. M. Ross, and A. R. Kovscek, Society of Petroleum Engineers Journal, 22(6), 1760-1777 (2017).
0
0.2Top down imaging: whole core images (2.5 cm diameter) with CO2, Kr, or Xe in pore space and adsorbed• transient, • different gas types, • including stress
Top Down ImagingExample – Shale, CO2 Storage Capacity (/)
CT voxel: 250 x 250 x 1000 µm
300 µm 30 µm
P
OM
P – Pyrite; OM – Organic Matter; Matrix – mixture of clay and carbonate
1 inch diameter
Pixel Size: 1.45 µm
Pixel Size: 366 nm Pixel Size: 74 nm
20 40 60 80 100
10
20
30
40
50
60
70
80
90
100
0
0.05
0.1
0.15
0.2
0.25
/
Aljamaan, H. C. M. Ross, and A. R. Kovscek, Society of Petroleum Engineers Journal, 22(6), 1760-1777 (2017).Vega, B., C. M. Ross, and A.R. Kovscek, Society of Petroleum Engineers Journal, 20(4) 810-823 (2015Foute, L., Nanoimaging of Shale Using Electron Microscopy Techniques, Stanford University (2019).
SEM MosaicSEM Multiscale Images TEM Multiscale Images
Pixel Size: 2 nm
100 nm
Segmented TXM voxel: 30 x 30 x 30 nm
9
Toward CO2 Miscible Injection
2
@ P > MMP
CO2zero-entry capillary pressure barrier
oil
• Questions
• Does CO2 penetrate matrix at small pressure
gradients?
• Are miscible recovery mechanisms similar to
conventional EOR?
• Does repressurization hinder recovery?
(Actually) Nitrogen Displacing KryptonEagle Ford Shale
Elkady, Youssef, Imaging of Enhanced Gas Recovery from Eagle Ford Shale, Stanford University (2019).
• Breakthrough of CO2 between 0.45
and 1.2 PVI (2nd sample bag)
• 90% of gas recovery after 17 PVI
• CO2 gas fully displaces Kr –
confirmed by degassing core to
atmospheric
CO2 versus N2 Displacing Kr Results
12
Sorption Isotherms
Elkady, Youssef, Imaging of Enhanced Gas Recovery from Eagle Ford Shale, Stanford University (2019).
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10
Kryp
ton
Rec
over
y %
PVI
N2 Displacing Kr CO2 Displacing Kr
Chattanooga
Eagle Ford
Western Gulf
TX-LA-MSSalt Basin
Uinta Basin
Devonian (Ohio)Marcellus
Utica
Bakken***
Avalon-Bone Spring
San JoaquinBasin
MontereySanta Maria,Ventura, Los
AngelesBasins
Monterey-Temblor
Pearsall
Tuscaloosa
Big HornBasin
DenverBasin
Powder RiverBasin
ParkBasin
Niobrara*
Mowry
Niobrara*
Heath**
ManningCanyon
AppalachianBasin
Antrim
Barnett
Bend
New Albany
Woodford
Barnett-Woodford
Lewis
Hilliard-Baxter-Mancos
Excello-Mulky
Fayetteville
Floyd-Neal
Gammon
Cody
Haynesville-Bossier
HermosaMancos
Pierre
Conasauga
MichiganBasin
Ft. Worth Basin
Palo DuroBasin
PermianBasin
IllinoisBasin
AnadarkoBasin
Greater Green River Basin
Cherokee Platform
San JuanBasin
WillistonBasin
Black WarriorBasin
Ardmore Basin
Paradox Basin
RatonBasin
Montana Thrust
Belt
Marfa Basin
Valley & Ridge Province
Arkoma Basin
Forest City Basin
PiceanceBasin
Lower 48 states shale plays
0 200 400100 300
Miles
±
Source: Energy Information Administration based on data from various published studies. Updated: May 9, 2011
BasinsShale plays
Stacked plays
BasinsCurrent playsProspective plays
* Mixed shale & chalk play
** Mixed shale & limestone play
***Mixed shale &tight dolostone-
siltstone-sandstoneIntermediate depth/ ageShallowest/ youngest
Deepest/ oldest
Apparatus: For huff-n-puff and CO2 Flood
8
Confining pressure
Collection system
BPR
Bottom Top
N2
N2
Port 1
Port 2
Port 3
Heating tape
Temperature controller
Collection system
BPR
N2
CO2
Huff-n-Puff
Countercurrent
9
Confining pressure
Collection system
BPR
Bottom Top
N2
N2
Port 1
Port 2
Port 3
Temperature controller
Heating tape
CO2
Cocurrent
9
Temperature controller
Confining pressure
Collection system
BPR
Bottom Top
N2
N2
Port 1
Port 2
Port 3
Heating tape
CO2
45 oC10
Huff-n-Puff CO2 Injection
injection
injection
Vega, B. W. J. O’Brien, and A. R. Kovscek, Proceedings of the 2010 SPE Annual TechnicalConference and Exhibition, Florence, Italy, 19–22 September 2010.
45 oC11
Cocurrent CO2 Injection
injection
production
injection
production
Vega, B. W. J. O’Brien, and A. R. Kovscek, Proceedings of the 2010 SPE Annual TechnicalConference and Exhibition, Florence, Italy, 19–22 September 2010.
Summary of Test Results
12
TEST 1 2 3 4
Flow conditions Immiscible Immiscible Near Miscible Miscible
kr to decane, mD 0.023 1.32 1.32 1.32
Sg after depletion 0.11 0.38 N/A N/A
CO2 after countercurrent 0.21 0.47 0.25 0.54
CO2 after cocurrent 0.32 0.66 0.36 0.93
Oil recovery (depletion) 0.11 0.37 N/A N/A
Oil recovery
(countercurrent)0.0 0.09 0.25 0.45
Oil recovery (cocurrent) 0.25 0.19 0.10 0.48
Total recovery for CO2
flow0.25 0.28 0.35 0.93
Vega, B. W. J. O’Brien, and A. R. Kovscek, Proceedings of the 2010 SPE Annual TechnicalConference and Exhibition, Florence, Italy, 19–22 September 2010.
CO2 Distribution Observations
• Multiscale (cm to nm) imaging
• Gas accessibility and storage capacity in intact shale cores
• SEM mosaics of either core face or interior slices
• Elemental mapping and interpretation
• Image registration methods (same resolution and
multiscale)
• Gas storage and its distribution is controlled by
• porosity
• accessibility
• sorption capacity of minerals and organic matter
20
Outline
Shale and CO2 Cooptimized EOR & Storage
CO2
zero-entry capillary pressure barrier
oil
zero capillary entry pressure barrier 0
0.1
0.2
0.3
0.4
0.5
0.6
0 2000 4000 6000 8000 10000 12000 14000 16000days
CO2 injectionSolvent InjectionWAG 0.01 PV - CO2WAG 0.01 PV - solventGAW - CO2GAW - solventWC - CO2WC - solvent
Shale EOR and CO2
CO2
zero-entry capillary pressure barrier
oil
Main Points
• We know a lot about …
• miscibility
• unstable flow
• role of heterogeneity
• WAG
• optimization
• EOR using anthropogenic
CO2
• But, challenges remain …
• cooptimization of EOR and
storage
• phase behavior and
transport in tight media
• coupled transport, reaction,
and geomechanics
• unstable flow
https://www.acs.org/content/acs/en/pressroom/presspacs/2015/acs-presspac-november-18-2015/profit-from-co2.html
23
LaBarge, WY
Rangely Colorado
Gas ProcessingPlant
Gas Injection Well
Mixture of MethaneCarbon DioxideHeliumHydrogen Sulfide
Utah
Driven solely by economics
Ca
n w
e u
se
an
thro
po
ge
nic
CO
2fo
r E
OR
?S
eq
ue
str
ati
on
to
da
y
Can we use anthropogenic CO2 for EOR?Rangely Field, CO Performance
• separate CO2 from produced
natural gas
• use CO2 for enhanced oil
recovery (EOR)
• 114 million bbl incremental
production (about $5.5 billion
at $50/bbl)
• extended significantly the life
of the fieldIncremental
Production
Masoner and Wackowski, SPERE, Aug 1995
EOR vs Sequestration
• EOR design: max{recovery} U min{CO2 injection}
• Cooptimization EOR and CCS: max{recovery and Sg} U min{CO2 cycling}
• Breakthrough of injected gas and gas cycling limits EOR processes:
Np* = oil recovery - energy to recompress cycled gas
Synthetic reservoir (PUNQ S3)
permeability, kx (md)1 1000 log 10
truth model
• dome with gas cap
• bounded by faults and
aquifer
• PV = 30 Mm3 = 0.2 Bbbl
• depth to top = 2340 m
• ~24°API
• sand & shale
sequences
19 x 28 x 5 blocks, 1761 active
Kovscek, A. R. and M. D. Cakici, Energy Conversion and Management, 2005.
Solvent Immiscible
Name pure CO2
N2 0 0CO2 0.6667 1H2S 0 0Methane 0 0Ethane 0.1250 0Propane 0.1250 0i-Butane 0.0833 0
Gas injection
Kovscek, A. R. and M. D. Cakici, Energy Conversion and Management, 2005.
• Water Alternating Gas Drive
(WAG)
• Gas Injection after Water
Flooding (GAW)
• GOR Controlled Production
Wells with Injection Well
BHP constraints (no water)
• Np* = Np - oil energy to compress
produced gas
0.0E+00
5.0E+07
1.0E+08
1.5E+08
2.0E+08
2.5E+08
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5PVs injected
kg-m
of C
O2
wag 0.01 PV - CO2wag 0.1 PV - CO2wag 1 PV - CO2wag 0.01 PV - solventwag 0.1 PV - solventwag 1 PV - solventCO2 injectionsolvent injection
kg o
f CO
2 in
rese
rvoi
r
The Problem With WAG and CCSFill your reservoir with water not CO2
Kovscek, A. R. and M. D. Cakici, Energy Conversion and Management, 2005.
Well Control: Active Injection and Production
Constraints
Kovscek, A. R. and M. D. Cakici, Energy Conversion and Management, 2005.
Average Pressure and GOR
0
50
100
150
200
250
300
350
400
0 2000 4000 6000 8000 10000 12000 14000 16000days
0
2000
4000
6000
8000
10000
12000WC1 - FPR WC2 - FPR WC3 - FPR WC0 - FPR
WC1 - GOR WC2 - GOR WC3 - GOR WC0 - GOR
Kovscek, A. R. and M. D. Cakici, Energy Conversion and Management, 2005.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 2000 4000 6000 8000 10000 12000 14000 16000days
CO2 injectionSolvent InjectionWAG 0.01 PV - CO2WAG 0.01 PV - solventGAW - CO2GAW - solventWC - CO2WC - solvent
fracti
on
al o
il r
eco
very
(N
p* /O
OIP
)
CO2
solvent
Oil Recovery
0
0.1
0.2
0.3
0.4
0.5
0.6
0 2000 4000 6000 8000 10000 12000 14000 16000days
CO2 injectionSolvent InjectionWAG 0.01 PV - CO2WAG 0.01 PV - solventGAW - CO2GAW - solventWC - CO2WC - solvent
reserv
oir
uti
lizati
on
(V
CO
2/P
V)
Storage Utilization
Kovscek, A. R. and M. D. Cakici, Energy Conversion and Management, 2005.
Geomechanics and Seal Capacity
• How will CO2
injection affect the
reservoir seal?
• Did production and
depletion affect the
seal?
• What are the
geomechanical
mechanisms
governing capacity?
Trap and Seal Framework
Cooptimization Summary
• Well control (GOR and pinj as control parameters)
– same oil recovery as WAG process
– 2.5 times more CO2 utilization wrt WAG
– significant effect on recovery for solvent injection
• Results show little sensitivity to the reservoir
model (i.e., distribution of permeability)
• Some sensitivity wrt values of GOR and pinj
• Sensitive to constitutive relationships
35
Our approach to CO2 Enhanced RecoveryMulti* = multiscale, multiphysics, multiphase
Pore Scale• Capillary forces
• Stokes flow
• Viscous dissipation
• Rock/fluid interaction & reaction
• DLA, Anti-DLA
• Pore network simulation
• Direct numerical simulation
• Microfluidics
• MicroCT
Darcy Scale • Viscous & gravity forces
• Darcy’s law
• Coupled flow and mechanics
• Mobility control
• Reduction of gas production and recycle
Relative Permeability
StatisticalInformation
Small Scale Large Scale
Acknowledgements
• SCCS
• Stanford Synchrotron Radiation Lightsource, SLAC
• Stanford Nano Shared Facilities, SNSF
• Collaborators
36
KhalidAlnoaimi
HamzaAljamaan
Cindy Ross
BeibeiWang
BoliviaVega
YoussefElkady
DenizCakici
Questions?