Gas and Oil Producing Shale
and Nonconventional Oil
Opportunity with Knowledge
and Technology
r. marc bustin
DEFINITION OF
UNCONVENTIONAL RESOURCES
• hydrocarbon distribution controlled not necessarily by
buoyancy – no obvious reservoir seal– Low Matrix Permeabilities (<0.1 md) or high viscosity fluids
– Adsorption Mechanisms and diffusion maybe important
– Pressures maybe abnormal
• economic recovery require non-standard exploration and
operating practices– Geomechanics and geochemistry disproportionally important in delineating
sweet spots
– Wellbore and Completion Designs
– Well and Formation Testing Procedures
– Development Strategies
UNCONVENTIONAL GAS AND
RESOURCE PLAYS
TIGHT GAS SANDS
• Continuous Deposition
• Low Permeability
• Both Traditional and “Basin-Center” Settings
COALBED METHANE
• Self-Sourcing Reservoir
• Gas Adsorbed in Coal
• Requires Depressuring and Usually Dewatering
GAS and Oil Prod. SHALES
• Self-Sourcing Plus Traditional Porosity Reservoirs
• Gas Adsorbed in Organic Matter
• Requires Pervasive Natural Fract. Network or K pathways
RESOURCEPLAYS
Kuuskraa, 2006
METHANE
HYDRATES
UNCONVENTIONAL GAS AND
RESOURCE PLAYS
TIGHT GAS SANDS
• Continuous Deposition
• Low Permeability
• Both Traditional and “Basin-Center” Settings
COALBED METHANE
• Self-Sourcing Reservoir
• Gas Adsorbed in Coal
• Requires Depressuring and Usually Dewatering
GAS and Oil Prod. SHALES
• Self-Sourcing Plus Traditional Porosity Reservoirs
• Gas Adsorbed in Organic Matter
• Requires Pervasive Natural Fract. Network or K pathways
RESOURCEPLAYS
Kuuskraa, 2006
METHANE
HYDRATES
opportunity
unconventional
reservoir rock
conventional
reservoir rock
UNCONVENTIONAL OIL PLAYS
modified form Russum, 2010
Conventional Oil in Unconventional Rocks
Unconventional Oil in Conventional Rocks
Russum, 2010
0
opportunity
opportunityopportunity
opportunity - understanding and
evaluating rock systems and application of
appropriate technologies can result in
commercial exploitation of hydrocarbon
resources previously considered sub
economic
assess to opportunity- network of
contacts and companies who want to do
business and savvy to make it work
East-West Competitive Advantage
• experienced technical professionals –
access to ideas, technology and innovation
• strong committed board of directors
• business savvy
• strong and very very aggressive financial
support
• access to opportunity- strong land position
and access to much more
GAS SHALES- source rocks with retained HCs
Cap Rock
Source Rock
Reservoir Rock
Gas
Oil
Gas and Oil
Burial ofOrganic Rocks
Kerogen
Biogenic Gas
ThermogenicGas and Oil
Wet Gas
Dry Gas
background
Oil & Gas Shales- source rocks with retained HCs
GAS SHALES- source rocks with retained HCs
Cap Rock
Source Rock
Reservoir Rock
Gas
Oil
Gas and Oil
Burial ofOrganic Rocks
Kerogen
Biogenic Gas
ThermogenicGas and Oil
Wet Gas
Dry Gas
Antrim
Eagleford
Haynesv.
Oil & Gas Shales- source rocks with retained HCs
background
Green
River
Conventional Oil in Unconventional Rocks
Unconventional Oil in Conventional Rocks
Conventional Oil in Unconventional Rocks
Unconventional Oil in Conventional Rocks
heavy oilreservoir access
tight rock
GAS SHALES- source rocks with retained HCs
Cap Rock
Source Rock
Reservoir Rock
Gas
Oil
Gas and Oil
Burial ofOrganic Rocks
Kerogen
Biogenic Gas
ThermogenicGas and Oil
Wet Gas
Dry Gas
Antrim
Eagleford
Haynesv.
0.38 nm
background
Oil & Gas Shales- source rocks with retained HCs
Complexities and Predictions
ANTRIM SHALELEWIS SHALEOHIO SHALE
facies controlled permeability
fracture or fraced controlled permeability
haynesville barnett fayetville woodford ohio lewis
montney eagle ford
background
Definition: Gas/Oil Shale
• Shale gas/oil is defined as a fine grained reservoir in which gas/oil is self sourced and some of the gas is stored in the sorbed state
• Sorbed gas is predominately stored in the organic fraction– so organics present
• Not just ‘shale’Bustin, 2005, AAPG
Background
Clay <2 um
Silt <62.6>2 um
limestone ie. Eagle Ford, Muskwa
dolomite ie. Montney
chert ie Woodford
mudstone ie.Marcellus, Muskwa
siltstone/vfg sandsone ie. Lewis
shale ie. Anrtrim
Classify Petroleum Systems as
Conventional …
USGS 2003
…or Continuous
USGS 2003
Characteristics of ‘Continuous’
Accumulations• Regional in extent
• Diffuse boundaries
• Low matrix permeabilities
• No obvious seals or traps
• No hydrocarbon/water contacts
• Close to or are source rocks with non expelled hydrocarbons
• Low recovery factors
• Includes tight sandstones, coalbed gas, oil and gas in shale and chalk
NATURAL GAS PYRAMID
HighQuality
Medium Quality
Low Quality
Tight Gas Sands
CBM Gas Shale
Low Btu Gas Hydrates / Other
1000 md
100 md
1 md
0.00001 mdProduced
Reserves
Undiscovered Resources
New Fields CBM
Tight Gas Gas Shales Low Btu
Emerging / Future ResourcesSub-Volcanic New Gas Shale New Tight Gas
Deep CBM Basin-Center
Gas Hydrates / Other
technology price
0.5 mm
Eagle Ford Shale
Wet Barnett
Wet Marcellus
Duvernay
Implications of the New Gas Shale World
What are the World Gas Shale
Resources and Reserves?
estimates based on source rock studies with
assumptions about how much gas retained in source
rocks
-Rogner 1997 estimate Resource Endowment at 16,119
TCF
-US NPC estimates total unconventional at about 32 000
TCF
-IEA World Energy Endowment assumes 40% of
endowment is recoverable – 6350 TCF
-so we are pretty much making intelligent guesses.....
US NPC SPE 68755
Region Coalbed
Methane (TCF)
Shale Gas
(TCF)
Tight Gas
(TCF)
Total
(TCF)
North America 3017 3842 1371 8228
Latin America 39 2117 1293 3448
Western Europe 157 510 353 1019
Central and East
Europe
118 39 78 235
Former Soviet Union 3957 627 901 5485
Mid East & North
Africa
0 2548 823 3370
Sub-Saharan Africa 39 274 784 1097
Centrally planned Asia
and China
1215 3528 353 5094
Pacific (OECD) 471 2313 705 3487
Other Asia Pacific 0 314 549 862
South Asia 39 0 196 235
World 9051 16112 7406 32560
Estimates of World Wide Distribution of Unconventional Gas Resources
Source: "Tight Gas Sands", Journal of Petroleum Technology, June 2006, Page 86-93.
Table 1 - Distribution of Worldwide Unconventional-gas resources (After Rogner 1996, Taken from Kawata and Fujita 2001)
North American Gas Production Forcast
EnCana, 2010, IP
Producing Shale
Plays
Horn River100-150 Bcf/sect.
Montney100 Bcf/sect.
Barnett140-160
Bcf/sect.
Fayetteville25-65 Bcf/sect.
Haynesville150-200 Bcf/sect.
Marcellus45 Bcf/sect.
Woodford100 Bcf/sect.
Antrim6-15 Bcf/sect.
Utica45 Bcf/sect.
Lewis40 Bcf/sect.
Ohio5-10Bcf/sect.
New Albany7-10Bcf/sect.
Eagle Ford50-150 Bcf/sect.
Duvernay? Bcf/sect.
? Oil
green denotes
liquids production
based map
modified from
EnCana IP. 2009
TransCanada Pipeline (June 2010, Investor Presentation)
Projected Gas Supply –TransCanada Pipeline
EnCana Investor Presentation, 2010
Range Resources, April 2010
Trend to fewer wells with longer lateral lengths
with more frac stages
Southwest Energy, March 2010
the learning curve
continues
to flatten
The costs of shale gas
Source: Chesapeake Energy:
January 2010 Investor Presentation
Source: Vello Kuuskraa, President of ARI Inc, in presentation to the Copenhagen summit, 12
December 2009
Horsfield and Schulz, 2010 AAPG
Conventional Gas Distribution
Source: Oil and Gas Journal
unconventional opportunities exist where ever
conventional production exists
and many other areas
Geological Characteristics Common to
Producing Gas and Oil Producing Shales
• Organic rich
• Marine to transitional marine
• Interbedded source and seal
• Comparatively thick
• Permeability enhanced by fracturing
or interbedded facies with higher
perm.
What gas/oil shale properties are
important?
• gas/liquid composition
• gas and liquid capacity and content-sorbed and free gas
• permeability- fracture or facies controlled
• thickness
• lateral extent
• ease of completion, reservoir access
gas and oil producing shales
• producing shales range from organic rich,
fine grained rocks such as the Antrim or
Ohio Shale to variable facies rocks such
as the Lewis Shale
Background
Ohio
Lewis
Background
New Albany
SOME EXAMPLES
Barnett
Antrim
TEM
50 000 nm
SEM
Background
Shales are heterogeneous rocks
200 000 nm
Outcrop
Hand
Spec.
Light
FESEM
200 nm
4500
Background
Pressure and Temperature Space of
Producing Shales
0 20 40 60 80 140
0
1500
3000
Temperature ºC
Barnett
LewisOhio
New AlbanyAntrim
Pre
ss
ure
(PS
IA) Woodford
Caney
Fayetteville
Eagle Ford
Muskwa
Haynesville
Utica
Marcellus
Maturity and Organic Matter Content
Background
1.6
Antrim
New Albany
Barnett
BIOGENIC GAS
OIL WINDOWRom
ax
( %)
0
0.4
0.8
1.2
TOC (%)
0 4 8 12 16 20 24
THERMOGENIC GAS
Woodford
Caney
Fayetteville
Muskwa
2.0
Haynes-ville
Eagle Ford
Utica
Marcellus
Ohio
Lewis
Complexities and Predictions
ANTRIM SHALE
LEWIS SHALEOHIO SHALE
facies controlled permeability
fracture or fraced controlled permeability
Mu
skw
a/O
tte
r P
ark
/Evie
No
rdeg
g
Bu
ckin
gh
ors
e
Sh
aft
sb
ury
Mo
ntn
ey
Complexities and Predictions
ANTRIM SHALE
LEWIS SHALEOHIO SHALE
Tight SSTrue Shale/Porcellanite
What We Know!
• rocks referred to as gas/oil shales
range from true shales to tight sands
• individual formations, members or
units within a shale unit may be
extremely heterogeneous in
mineralogy and fabric and hence pore
system and flow characteristics
Shale
Mapping TOC
ThicknessTOC
Geochemistry
Gas CapacitiesAdsorbed Gas
Free Gas Solution Gas
Producibility
Moisture
Maturity
Al2O3 fraction
Fracturing
Temperature
Pressure
Area
PorositySedimentology
Diagenesis Silica contentsCoarser horizons
Gas/Oil Shale Model
So, Sg, Sw,
Permeability
Wireline logs
fabrics/fracturesthickness
effective stress
permeabilitydiffusivity
Reservoir exploration and
development
TOCPorosity
gas in place
gas in place deliverability
fabrics/fractures
effective stress
permeabilitydiffusivity
Reservoir exploration and
development
TOCPorosity
thickness
gas in place
gas in place deliverability
Outline
Factors Governing OOIP & GIP in Shale
• Area
• Thickness
• Pressure
• Temperature
• Porosity
• Gas Saturation
• Area
• Thickness
• Pressure
• Temperature
• Total Organic
Content
• Maturity
Free Gas in Pores
and FracturesAdsorbed Gas
Total Gas = Free Gas + Adsorbed Gas+
Solution Gas
Solution Gas
• Area
• Thickness
• Pressure
• Temperature
• Total Bitumen/
Liptinite content
• Maturity
BACKGROUND
OGIP Workflow• Isopach Net and Gross Pay
• Frac barriers
• Structure Map
• Vertical Depth
• Temperature Gradient
• Pore pressure Gradient
• Bulk density
Adsorbed
Gas
Free
Gas +
Liquids
Solutio
n
Gas
Adsorption
Isotherms on
samples of
varying TOC
Measurement
TOC on
representative
samples
Calibration
well logs
to TOC
Interpolation
adsorbed gas
through pay
interval via
calibrated logs
Measurement
of pore
compressibility
Measurement
total porosity,
Sw, So
representative
samples
Calibration
porosity, Sw
and So to
well logs
Interpolation
free gas + HC
liquids in
net pay via
calibrated logs
Measurement
or calculation
gas solubility
reservoir P & T
& salinity
Measurement
total
mobile water
Interpolation
of solution gas
through pay
interval via
calibrated logs
Calibration
porosity, Sw
and So to
well logs
TOTAL OGIP = adsorbed + free + solution gas + liquid HCs
Gas
Compositio
n
Canister Desorption
gas sampling f(t)Gas Chromatography± isotopic analyses
Accessible OGIP = Total OGIP/m3 ∙ Stimulated Reservoir Volume
sample basedlog based
• type curves are decline curves that are anticipated to (or do) reflect the
production profile of a well with a particular completion (ie lateral
length, number of stages etc.) and represents the P50 case
• at exploratory stage type curves of what are considered to be
analogous reservoir are used– with early production IPs are
manipulated and later ‘b’
• typically operational changes and more stages result in higher IPs with
typcally similar curve shapes
Applying Type Curves
number of stages
EnCana, 2009 IP
fabrics/fractures
effective stress
permeabilitydiffusion
Reservoir exploration and
development
TOCPorosity
thickness
gas in place
gas in place deliverability
whether a rock is currently fractured and its ability tobe fractured are dependent on mechanical properties–which vary with mineralogy, fabric and diagenesis andhence stratigraphy
goal is to develop a geomechanical model of thepotential reservoir to assist in drilling, completions,and development
Geomechanics- Rock Mechanics
the future is mechanical stratigraphy
required for:• predicting orientation of frac (SRV)• density, width and orientation of natural fractures • optimal direction for horizontal wells– for stability
and for intersecting fractures that are open• borehole stability• change in reservoir permeability during production
requires knowledge of:
• in situ stress orientation and magnitude
• pore pressure
• pre existing rock fabric and moduli
• thermal and chemical state of reservoir and fluid
system
0
00
0
• appears most thermogenic gas and oil shales have FEW pre-
existing fractures or those that exist are healed
• object then is to shatter the rock during fracing to increase the
surface area available for drainage
• maximize the stimulated reservoir volume
• not to connect to a pre-existing fracture network
• many shales do not have a pre-existing k network
0
00
0
• appears most thermogenic gas shales have FEW pre-existing
fractures or those that exist are healed
• object then is to shatter the rock during fracing to increase the
surface area available for drainage
• maximize the stimulated reservoir volume
• not to connect to a pre-existing fracture network
• many shales do not have a pre-existing k network
0
20
40
60
80
100
0 20 40 60 80 100 120 140 160
Effective Normal Stress (Residual), s , MPa
Sh
era
Str
ess
,t,
MP
a
Mohr's circle at 14 MPa Mohr's circle 31 MPa Coulomb failure Envelope
Friction Angle = 44.19°
Linear Cohesion = 7 MPa
Stimulated Rock Volume (SRV) and shape of
SRV is a function of the in situ stress field,
mechanical properties of the rocks and frac
design and execution
Mayerhofer et al SPE 102103
Strong correlation between SRV
and production (excellent
correlation between number of
stages at IP)
σHmin=σHmax
σHmin>>σHmax
SRV estimated from microseismic
SRV function of completion
completion function of in situ
stress, rock properties and design
and implementation of frac
a farming operation- you don't frac it you
don't get the gas
http://www.ashdown.org.uk/spps/images/Carol_Talbot/BA2008_CarTal_Tractor%20ploughing%20field.j
pg
high density horizontal well pad
designed to ‘harvest gas’
Diffusion/
Mass
Flow
Matrix
Block
Darcy Flow
Coals- fracture (cleat)
spacing is so low that
matrix perm/diffusion is
not considered rate
limiting
Shales- fracture spacing
is commonly >5 cm and
matrix perm/diffusion
may be rate limiting
Geomechanics and
Permeability/Diffusion Rate
Permeability/Diffusion
• reservoir perm requires well tests
• matrix perm/diff can be measured in
lab
Diffusion/
Advection
5 nm
Desorption
controlling variables
fracture permeability
fracture fabric
effective stress
rock mechanics
matrix permeability/
diffusion
induced during fracs
existing fabric
depth
far field stress
moduli
mineralogyfabric
mineralog
yfabri
ceffective
stressrock
mechanicsgas
composition
deliverabilitypressure/temperature/fluid properties
fracture spacing
Integrated Optimization Process
Quirk, 2010
Integration Optimization
Process• 1. It helps answer the questions…How many
fracs do I need in my horizontal wellbore? How
big should my fracs be?
• 2. It integrates many types of data into one
reservoir package, maximizing value for your
information.
• 3. It provides a way to model fractures in the
complex fracturing we find in shale gas
reservoirs (i.e. Horn River/Barnett).
• The process can be used in any reservoir.
Quirk, 2010
Information that Collecting a Microseismic Dataset
Provides
• Fracture Azimuth
• Fracture Length
• Fracture Height
• Fracture Complexity
• Calculation of Stimulated Reservoir Volume
• Evaluation of the effectiveness of the
completion system
• Calibrated Fracture Modeling and Integration
of Microseismic into a Reservoir Simulator
Quirk, 2010
Trican fracing shale well in north eastern British Columbia
Horn River Basin
• 11 mapped slickwater stages
• Generally complex fracturing
• Long fracture half lengths
• NE-SW fracture azimuth
• Stimulated Reservoir Volume
(SRV) is crucial to production
– Portions of the horizontal are
under-stimulated
Apache Website
Horn River Basin from
http://www.apachecorp.com/Resources/Upload/PrevArticleFiles/files/
Apache_2008_Analyst_Review_08_Canada.pdf
Conclusions
• Low permeability reservoirs require large SRVs with
small fracture spacing and adequate frac conductivity
• Important to understand parameters in the reservoir that
will create complexity so fracture spacing in the SRV can
be understood
• Engineering measures to increase SRV and frac spacing
– Length and orientation of horizontal well
– Treatment size
– Number of stages, number of perf clusters
– More stages and clusters in a cased/cemented completion
increased likelihood of dense fracturing
– Zipper fracs, Simul-fracs
developing a strategy, ranking
prospects.....where do you start?vast resources of gas in tight rock either sorbed or free state– how do you explore?
screens:
1. thickness
2. lateral extent
3. toc
4. maturity
5. mineralogy
6. reservoir accessibility
7. rock mechanics
8. frac barriers
9. fluid sensitivity
10. reservoir pressure
11. cost
12. Poisson’s Ratio
13. Mud logs./shows
need to know at start if
there is enough gas in
place to warrant the cost
of exploring and
completion– what is the
size of the prize)
development risk
max. SRV; optimization of
drilling and completions
Attributes
Lithology fine grained, will indurated
Thickness > 40 m
Current TOC >1% (min. not known)
Effective Porosity to Gas >2.5%
Young Modulus > 4 mmpsia
Poisson's Ratio <0.25
Clay Content <30% (no water sensitive clay)
Pressure Gradient >.5 psi/foot
Mud Log Gas relative but evidence of gas
Gas Shale Target Parameters
Desired
Matrix
porosity
Matrix
Perm.Maturity In Situ
StressPressure E ν
PROSPECT WINDOW
Dep
th\D
iag
en
esis
Rock Mechanics
summary
Matrix
porosity
Matrix
Perm.
Total
Gas
Rock
Mechanics/Fractures
PROSPECT WINDOW
Dep
th\D
iag
en
esis
optimum zone
trade off between
many variables and
will be shale
specific
summary