Unconventional Resources and Basin Evolution · 30 8 4 3 2 2 2 1 1 y A a a ia a ia ria la y...
Transcript of Unconventional Resources and Basin Evolution · 30 8 4 3 2 2 2 1 1 y A a a ia a ia ria la y...
UnconventionalResources and Basin Evolution
Discuss some regional scale controls (plate to basin) on unconventional resources.
Illustrate with five examples (source rock, tight sand and CBM reservoirs).
Objective
Types of Unconventional Resources – Review
Global Screening Analysis of a Few Regional Factors
Selected Examples
Reservoir Deposition and Characteristics
Burial – Maturation and Diagenesis
Uplift and Exhumation
Closing Remarks
Outline
Unconventional Resources –
Categories
~ G a s
~ O i l
~ Heavy Oil
~ Extra Heavy Oil
~ Bitumen/Tar
~ C
on
ven
tio
na
l Res
ervo
irs
~ Ti
gh
t R
eser
voir
s
Reservoir Permeability (k, md)
Flu
id V
isco
sity
(μ
, cp
)
Fracture Stimulation
Therm
al/So
lvent M
etho
ds
Improving Flow:Potential Approaches
Mobility = Permeability / Viscosity
Reservoir Permeability (k, md)
Flu
id V
isco
sity
(μ
, cp
)
Tar SandMining
Steam / Solvents
(e.g. SAGD, CSS, Fireflood,
etc.)
Shale Oil
Sh Gas
Tight Oil
CBM/Tight Gas
Conventional Oil
Conventional Gas
Enhanced Cold Flow (CHOPS)
Note –In reality, there is much overlap between resource types / depletion strategies.
HC Resource Types: Permeability vs. Viscosity
HEAVY OIL
TIGHT OIL & GAS
Unconventional Types:Heavy OilTight Sandstone/CarbonateSource Rock (“Shale”)Coal Bed Methane
Global Screening Analysis of Basin Factors
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8
4
3
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2 1 1
Unconventional Plays: Country
USA
Canada
China
Australia
Argentina
Russia
Algeria
Venezuela
Germany
Regional/Basin Controls on Unconventional Resources - Database
• 87 unconventional plays screened. 54 further analyzed based on materiality and maturity.
• Of these 54, 45 plays are significantly commercialized (e.g., Permian Wolfcamp); 9 are emerging with commercial promise (e.g., Nequen Vaca Muerta).
• Representative, but not necessarily comprehensive.
• Dominated by US/Canada because of commercial/infrastructure/regulatory considerations (and favorable geology).
US
Canada
China
Aust.19
22
8
5
Unconventional Plays: Types Evaluated
Tight Sand
SourceRock
CBM
Heavy Oil
N=54
Regional/Basin Controls on Unconventional Resources - Depositional BasinUnconventional plays occur in all kinds of basins – many pathways to success.
Forelands are the most important.
The prominence of forelands, in part, probably includes a bias related to commercial considerations –unconventional developments generally require an onshore setting.
But also, rapid flexural subsidence in foreland basins is often associated with thick source rocks (“shale reservoirs”) and tight reservoir sandstones – discussed later.
Lastly, volcanic arc association may be an additional source of nutrients.
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16
5
6
11
2 1 1
Unconventional Plays: Depos. Basin
Foreland
Complex Foreland
Cratonic Sag
Extensional
Passive Margin
Back-Arc
Fore-Arc
Transpressional
0
5
10
15
20
25
Unconventional Plays: Reservoir Age
Heavy Oil
Tight Sand
CBM
Source Rk.
Regional/Basin Controls on Unconventional Resources - Reservoir Age
Oceanic Anoxic EventsJenkyns (2010)Brennecka (2011)Algeo et al. (1994)
1 1 1123
1
2
3
Source Rock and CBM Plays – Age
Global HC Source Rocks vs. Age
0
1
2
3
4
5
6
7
8
9
Source Rock and CBM Plays: Reservoir Age
CBM
Source Rk.
Source Rock Reservoir Plays Only
Deposition:Reservoir Presence / MineralogyOrganic Richness
Burial:Reservoir Compaction/DiagenesisSource MaturationPressure Development
Exhumation & Deformation:Folding/FaultingNatural FracturesOil BiodegradationPressure ModificationDrilling Depth
Basin Evolution and Unconventional Play Elements
Sand reservoir
Marine source rock
Reservoir Deposition / Characteristics
Reservoir Presence / MineralogyOrganic Richness
Cross Section from Ettensohn (2019)
UTICA
MARCELLUS
OHIO
Taco
nic
Source Rock (“Shale”) Reservoirs: Appalachian Basin Example
CATSKILL DELTA
Acadian Unc. (Hutton)
Aca
dia
n
0
1000
2000
3000
4000
5000
6000
250270290310330350370390410430450470490510
Dep
th (
m)
Age (Ma)
Fold BeltTaconic Acadian
Uti
ca S
hal
e
Mar
cellu
s Sh
ale
Rh
ine
stre
etSh
ale
Oh
io S
hal
e
Appalachian Basin: Subsidence History, Shale Reservoirs and Orogenies
OROGENYEarly Collision
Alleghany
Acadian Unconformity
Bruner and Smosner, 2011 (DOE)
Devonian Source Rocks and Migration of Acadian Foredeep
Colpron and Nelson, 2009
1
2
3
4
5
5
7
8
Modified from Blakey
Late Devonian Orogenie
s and Organic Rich Mudstones
Black Shale Formations1 Ohio-Marcellus2 Chattanooga3 Antrim4 New Albany5 Woodford6 Sweetland Creek7 Bakken8 Exshaw, Duvernay, Muskwa
8
6
5
2
2
1
Eustasy
• Globally synchronous, spatially consistent.
• Rates high for durations < 0.1 m.y.
• Detailed internal reservoir architecture usually articulated at
this scale.
Accommodation Controls – Eustasy vs. Tectonics
Tectonics
• Temporally heterogeneous, but often correlative within a
basin.
• Magnitude spatially variable and often reversed (uplift and
adjacent subsidence) in same basin.
• Rates much higher than eustasy for durations > 0.5 m.y.
• General models more elusive – many “motifs”.
• Source rock and most tight sandstone reservoir intervals at
this scale.
Eustasy
Accommodation Change Rate vs. Time Duration (Log-Log)
Tectonics (Subsidence /
Uplift)
UpliftSubsidenceSea Level FallsSea Level Rises
MSL
1. Increase in subsidence-related accommodation.
2. Steepening of depositional profile.
3. Differentiation / partitioning of basin.
4. Arc volcanism for retroarc foreland basins.
5. At basin-scale, 2nd order unconformities in updip may be ~equivalent to MFS in downdip areas.
Tectonics and Source Rock Deposition
2
1
3
5
4
Tectonics and Source Rock Deposition: Possible Elements
MSL
1. Condensed section driven by subsidence (concentration of organic matter).
2. Steepened profile, enhancing upwelling (organic productivity)
3. Constructional coastal plain, enhanced terrestrial productivity. Nutrient transport (land plants, volcanic ash).
4. Differentiation of basin, potential silling of water column (dysoxia/preservation)
2
1
4
3
SOURCE TO SINK LAGAir Fall Ash
Terr. Plant Material
Arc-derived zircons (<250 Ma)
Recycled zircons (>250 Ma)
Volcanic Ash Deposition: Inferred Distribution
Adapted from Jacobs et al. (2019)
`
Relative Abund. of Volcanic Ash
Detrital Zircons: Frontier Fm., U. Cenomanian to L. Coniacian
WY
UT
Christianson et al. (1994)
high abund. of ash
Mowry-Niobrara time:• High arc flux• More ash distal
Frontier
Niobrara
MowryDakota
Permian Basin Paleogeography
Midland
Basin Eastern
Shelf
Palo Duro Basin
Matador Arch
Ozona Arch
Amarillo Uplift
Marathon
Orogenic Belt
Pedernal
Uplift
Orogrande
Basin
100 mi.
NMTX
OK
TX
Delaware
Basin
Val Verde
Basin100 km
EP
Guadalupe
Mtns
Delaware
Mtns
Sacramento
Mtns
San
Andres
Mtns
Hueco
Mtns
Sierra
Diablo
Apache
/Davis
Mtns
Sandia
Mtns
Glass
Mtns
Chinati
Mtns
CB
MD
LB
AB
AM
RW
AL
Basin
Platform
Platform Interior
Evaporitic Platform Interior
Alluvial Plain
Highland
Mountains
City/Town
Political
Boundary
Ancestral Rockies and Marathon/Ouachita
Orogenies 300 Ma (Late Pennsylvanian)
Permian Basin
PALEOGEOGRAPHY PRESENT DAY
Marfa
Basin
Hueco Canyon Fm. (Upper Wolfcamp)
Pow Wow Conglomerate (Middle Wolfcamp)
Hueco Mountains, Diablo Platform
Lower Wolfcamp Unconformity
• Culmination of Ancestral Rocky Mountain Orogeny.• Erodes to basement (in places) on Diablo Platform, Central Basin
Platform and Pedernal Uplift.• Transformation of basin architecture from simple ramp to partitioned
uplifts and deep basins (Pennsylvanian to Lower Wolfcamp).
Bone Springs
Wolfcamp
Wolfcamp
Spraberry
3rd
2nd1st
LowerUpper
Dean
Delaware Basin Central Basin Platform
Midland Basin Eastern ShelfWest East
AB
C
D
Avalon
Permian Basin: East-West Cross Section
Modified from WTGS, 1984
SL
-4
-6
C Ord S Dev Ms PermP Tr CzJur Cret
100 MY
Central Basin Plat.
Diablo Plat.
Eastern Shelf
Midland Basin
Delaware Basin
After Horak, 1985
Subsea D
ep
th (
km
)
Geol. Time
Passive Margin A.R.M.Orogeny
Post-Comp/Subsidence
Mid-Wolfcamp Unc.
-2
Permian Basin: Subsidence History & Tectonic Phases
Other Examples of Source Rock Reservoirs Associated with Tectono-Subsidence
50 km
20
0 m
Pinous et al (2001)
BazhenovVasyugen
Neocomian Clinoforms
Vartov
Pokur
EastWest Well Log Cross Section
MFS
Bazhenov, West Siberia Basin
Niobrara, Denver-Powder River Basins Vaca Muerta, Neuquén Basin
San.
Con.
Tur.
Pal.
Maa.
Cam.
66.0
72.0
84.2
89.7
93.9
86.3
W E
Modified from Rudolph et al (2015)
Depth (m)Geohistories
0 1000
2000
3000
4000
5000
6000
6570
7580
8590
9510
0
Depth (m)
Age
(Ma)
Alb.
Cen.
100.5
Sevier Foreland (BackbulgePosition)
Dynamic Subsidence
(+ Sevier Foreland)
Uplift / Low Subsidence*
Laramide Uplift and Flexural Subsidence Partitioning /
Differentiation
Modified from Rudolph et al (2015)
Niobrara
Leanza et al., 2011
AchimovShale Oil
Tight Oil
Uinta Mountains
Sevier Fold Belt
Deep Basin
WY
COUT
WYUT
ID
~ Middle Maastrichtian Paleogeography: Schematic Perspective View
Active Laramide Uplifts
Flexural Thicks
Sediment Transport
Tight Sandstone Reservoirs: Green River Basin Example
FluvialNext Slide
Southern Wind River BasinWind River MountainsNW Green River Basin
50 km
2.0
sec
49-013-20527
(proj. 4 km)COCORP Seismic LineWSW ENE
Velocity Pullup
49-037-21752
Bsmt
Pz
UCretUCret
Cz
Top Cret
Top Cam.
Bsmt?
LOADFLEXURE
Wind River MountainsSevier
Orogenic Belt
20 km
NW Green River Basin: Surface Geology and Lance (~Maastrichtian) Isopach
Pinedale Field (10 TCF)
Jonah Field (3 TCF)
NorthwestGreen River
Basin
49-013-20527
THIN
THICK
600
SouthernWind River
Basin
49-037-21752 Wind River Basin
Isopach based on Johnson et al (2014)
Gross Sand Map
49-035-2364427-T30N-R107W
49-035-2160811-T29N-R108W
49-035-218581-T28N-R109W
49-035-206088-T27N-R110W
49-023-2041829-T26N-R111W
Top Cretaceous(Datum)
Top Cretaceous(Datum)
NNESSW
~10 km
20
0 m
49-023-2051021-T25N-R112W
WINDRIVER
MOUNTAINS
Northwest Green River Basin:Upper Cretaceous
Stratigraphic Cross Section
Wind River Mountains
Sevier Orogenic
Belt
20 km
Pinedale Field (10 TCF)
Jonah Field (3 TCF)
NorthwestGreen River
Basin
49-013-20527
THIN
THICK
49-013-20063
600
SouthernWind River
Basin
49-037-21752
IP 6
.5 M
MC
FGP
D
Pinedale FieldJonah Field
IP 5
.4 M
MC
FGP
D
Perf’ed/Frac’ed Interval
Flexural Moat
Flexural Bulge
Burial / Maturation
Reservoir Compaction/DiagenesisSource MaturationPressure Development
USGS Assessment Team, 2002 Pranter and Sommer, 2011
Piceance Basin: Tight Sandstone Example (gas)
Basin-Centered Tight gas Play
50 kmC.I. = 0.1 km
-108°
40° 40°
-108°
-109°
39°39°
-109°
COUT
White River Uplift
Douglas Creek Arch
Adapted from Johnson et al (2004). Poor age control, possibly includes some upper Campanian in interval.
Uncompahgre Uplift
50 kmC.I. = 0.2 km
0.2
39°
40°
-108°-110°
39°
40°
-108°-110°
41° 41°
SanRafael Swell
THIN
Uncompahgre Uplift
White River Uplift
Uinta Mountains
Adapted from Johnson et al., 2017
COUT
Douglas Creek Arch
50 kmC.I. = 0.05 km
39°
40°
-108°-110°
39°
40°
41° 41°
SanRafael Swell
THIN
Uncompahgre Uplift
White River Uplift
Uinta Mountains
COUT
Adapted from Johnson et al., 2017
-108°-110°
Douglas Creek Arch
Upper Campanian - Maastrichtian Paleocene – Lower Eocene Upper Eocene
Reservoir Deposition Burial – Source Maturity and Porosity Evolution
Piceance Basin: Isopachs (km)Flexural thick developed west of a major Laramide uplift (White River Mountains).Provides space for deposition of thick non-marine reservoir interval (Upper Cretaceous).Deposition of overburden (Paleoc.-Eoc.) that matures coaly gas sources and develops capillary seal of tight sandstones.
Basin-Centered Tight Gas
Based on Saylor and Rudolph, in prep.
Flexure Models
Nucio and Roberts, 2003
Vitrinite Reflectance (Ro) at base of Mesaverde Gp.
Piceance Basin: Mesaverde Coal Maturity (Gas Source)
Peak Gas Generation
Onset of Generation
Rudolph
Deformation and Exhumation
Oil BiodegradationPressure ModificationNatural FracturesDrilling Depth
Exhumation
Piceance Basin: Burial History
• Approximately 1.2 km of exhumation in Neogene.
• Related to uplift of Colorado Plateau and more widespread epeirogenic uplift of western North America.
• Potential implications of exhumation:
• Shallower drilling targets• End of gas generation• Overpressure• Microfractures via
unloading
Rudolph
Fracture Example: Fruitland Coal Bed Methane, San Juan Basin, NM
Green River
PowderRiver
Denver
WR Wind River
Uinta
San Juan Raton
BHB
UU
FR
SC
G
U
WR
M
P
SJ
L
La
KP
NP
SP
RS
BT
Big Horn
MP
ShHa
Piceance
HU
DC
A
CA
N
FR
OC
200 km
CO
WY
NM
UT
Partly based on Heller and Lui (2016)
Basin
Uplift
Cz Volcanics
Thrust Belt Front
Fruitland CBM
Tremain et al. (1994)
Fruitland Cleat Orientation, Ft. Lewis, CO
Paleo-Stress Direction controls cleat orientation.Horizontal wells need to be oriented to intersect face cleats orthogonally.
Drill Direction
Research Questions of Industry Interest
Understanding the original porosity and permeability in tight unconventional reservoirs:Quantitative and accurate estimates of organo-porosity, inter-particle, intra-particle and adsorbed gas.Role of natural microfractures for permeability.
What is the impact of exhumation, which is common to many unconventional plays?Under what circumstances are hydrocarbons and pressure retained?What geologic histories lead to capillary entrapment (basin-centered gas) and can we reliably predict its occurrence?
What is the correct way to understand and model aggregate properties (“scale-up”) relative to flow. The fine-scale matters, but as it composites over ~50m frac height and 3 km lateral?Appropriate sequence stratigraphy models at the basin-wide, 2nd order scale (i.e., not LST-TST-HST schema)
What is the induced propped fracture network and can we better predict it?Microseismic only gives us a rough picture of the entire fracture network, most of which does not contain proppant.
Is there an environmentally more benign way to extract heavy oil, which makes up a large portion of remaining oil resources, but has a large carbon footprint.
Influence of volcanism on organic productivity.
Closing Comments
Predicting, understanding and developing unconventional petroleum reservoirs has historically relied on empirical indicators, direct analysis/interpretation and field experimentation.
However, the same basin-scale controls that are germane to conventional resources are also relevant to unconventional resources.
While these controls are unlikely to provide important commercial insights in established unconventional plays, they should be understood and utilized in poorly-constrained (“frontier”) settings.
Just as in conventional resources, there is not one (or even a few) success factors – there are many pathways to success (and even more to failure!).
So beware of purported general models, including what you have heard thus far - a consistent, integrated technical approach is more important.