Stratigraphic Framework of theWolfcamp – Spraberryof the Midland Basin
Lowell Waite
Department of GeosciencesPermian Basin Research LabUniversity of Texas at Dallas
October 8, 2019
Roswell Geologic Society
Permian Basin Research Lab at UT DallasDr. Robert J. Stern and Mr. Lowell Waite, Co-Directors
Goals:
• Advance understanding of all geologic aspects of the Permian Basin through open applied research,linking academia and industry
• Educate and better prepare students for professional careers in the oil and gas industry
-- established January, 2019 --
• Graduate courses offered:
https://labs.utdallas.edu/permianbasinresearch/
• Geology of the Permian Basin
• Petroleum Geoscience
• Paleo Earth Systems: Global Themes
Stratigraphic framework of Wolfcamp – Spraberry:Objectives
• Review the tectono-stratigraphic framework of the Wolfcamp and Spraberry deep-water units of the Midland Basin, west Texas
Note: although not specifically addressed, the framework outlined here is applicableto the Delaware Basin
• Briefly discuss the facies/characteristics of these rocks
• Highlight the differences between the Wolfcamp shale (A – D) and Spraberry depositional systems
Fold and thrust belt
Basement uplift
Shallow marine shelf
Reef / shoal complex
Deep marine basin
PrecursorTobosa Basin(Ord. to Miss.)
Greater Permian Basin Region
StudyArea
• Confluence of Marathon-Ouachita fold and thrust belt and Ancestral Rockies basement-involved uplifts(Penn. – early Permian)
Permian Basin Stratigraphy and Tectonic History
System
Permian
Pennsylvanian
Mississippian
Devonian
Silurian
Ordovician
Cambrian
Precambrian
Series
Ochoan
Guadalupian
Leonardian
Wolfcampian
Virgilian
Missourian
Desmoinesian
Atokan
Morrowan
Chesterian
Meramecian –
Osagean
Kinderhookian
Upper
Middle
Lower
U. Niagaran
L. Niagaran
Alexandrian
Cincinnatian
Mohawkian
Chazyan
Canadian
Ozarkian
Upper
Delaware BasinFormations
Wolfcamp
Cisco
Canyon
Strawn
Atoka
L. Miss Lm
Woodford
Devonian (Thirtyone)
Upper Silurian (Wristen)
Fusselman
Montoya
Ellenburger
Rustler
Lamar
Cherry Canyon
Brushy Canyon
BromideTulip Crk.
Mclish
Oil Creek
Sim
pso
n
McKee Sd.
Waddell Sd.
Connell Sd.
Joins
Bone
Spring
3rd Sand
Dewey Lake
Salado
Precambrian
Basement
Bell Canyon
Morrow
Barnett
DetritalLime
Cutoff Member /
1st Carb / Avalon
1st Sand
3rd Carb2nd Sand2nd Carb
Stray Sd
Castile
CBP & NW ShelfFormations
Wolfcamp
Cisco
Canyon
Strawn
Atoka
L. Miss Lm
Woodford
Devonian (Thirtyone)
Upper Silurian (Wristen)
Fusselman
Montoya
Ellenburger
Rustler
Tansill
Queen
Seven Rivers
Grayburg
Glorieta
Go
at
Se
ep
Cap
itan
BromideTulip Crk.
Mclish
Oil Creek
Sim
pso
n
McKee Sd.
Waddell Sd.
Connell Sd.
Joins
U. Miss Lm
Dewey Lake
Salado
Precambrian
Basement
Yates
Morrow (NW Shelf Only)
U. BarnettL. Barnett
DetritalLime
Midland BasinFormations
Wolfcamp
Cisco
Canyon
Strawn
Atoka
L. Miss Lm
Woodford
Devonian (Thirtyone)
Upper Silurian (Wristen)
Fusselman
Montoya
Ellenburger
Rustler
Tansill
Queen
San Andres
Seven Rivers
Grayburg
BromideTulip Crk.
Mclish
Oil Creek
Sim
pso
nMcKee Sd.
Waddell Sd.
Connell Sd.
Joins
Sylvan Sh.
Holt /Upper Leonard
Spraberry
Dean
Clear-
fork
U. Miss Lm
Dewey Lake
Salado
Precambrian
Basement
Yates
Wolfcamp D
UpperMiddle
Lwr Jo Mill
Wolfcamp A
Wolfcamp BWolfcamp C1Wolfcamp C2
Morrow
U. BarnettL. Barnett
Bend Lm
DetritalLime
Sh & Detrital
L. SPBY Sh
Bliss AbsentWilberns
Bliss / Hickory / Riley
Wichita / AboLower Clearfork
Yeso /
ClearforkTubb
Middle Clearfork
Upper Clearfork
Holt / Upr LeonardLwr San Andres
Lower San Andres
Upper San AndresDela
ware
Mtn
Gro
up
541
485
444
419
359
323
299
252
Ma
Early WFMP Event
Tectonic Phase
Strawn EventAtokan Event
Morrow Event
Penn. – Early PermianForeland Deformation
Tobosa Basin(Middle Ordovician to
Late Mississippian)
Moderate Subsidence
Post Orogenic Loading Rapid Subsidence;
Onset of HC Generation
Grenville Orogeny (1.3 to 1.0 bya)
Basement assembly and breakup of
Rodinia supercontinent
(~ 150 million yrs. duration)
(~ 30 million yrs.
duration)
( ~ 50 million yrs. duration )
Passiv
e M
arg
inA
ctive M
arg
in
mid – Wolfcamp unconformity
final basin fill/termination
Great American Carbonate Bank(Late Cambrian – Early Ordovician)
TOB
OSA
BA
SIN
PH
ASE
PER
MIA
N B
ASI
N P
HA
SE
(modified fromReed, unpub., 2016)
+5,000
(
Top Precambrian structure (courtesy of Mark George, PXD)
Ft. +5000
0
-5000
-10000
-15000
-20000
-25000
Midland
Basin
Delaware
Basin
Guadalupe
Mountains
datum: sea level0
-5,000
-10,000
-15,000
-20,000
Ft.
Eastern ShelfMidland BasinCentral
Basin
Platform
Delaware Basin
Woodford
Dewey Lake
Triassic
Strawn - Atoka
Woodford
Wichita - Abo
Clear Fork
Queen - Grayburg Tansill – Yates – Seven Rivers
Salado
(WTGS, 1984)
The Permian Basin
(maps: Ron Blakey, NAU/Colorado Plateau Geosystems)
Late Pennsylvanian • Icehouse climate; PB in humid-tropical setting (abundant rainfall)• Numerous high-freq., high-amplitude sea-level changes• Expansion of Penn seaway (long-term rise); stratified water columns• Continued tectonism in west Texas (Marathon-Ouachita FTB, rise of ARM)
A very dynamic time in
Earth history, especially in
west Texas
Wolfcampian – Early Leonardian• Waning icehouse, transition to greenhouse• Northward drift of Pangea• Increasing aridity & expansion of continental desert in western U.S.• Cratonic emergence / contraction of seaway (onset of long-term SL fall)• Culmination of tectonic pulses in W. TX (mid WC); Pacific arc volcanism (Late WC-Leon.);
PB enters rapid subsidence phase (Dean - Spraberry)
LATE PENNSYLVANIAN – EARLY PERMIAN EVOLUTION OF WESTERN PANGEA
2nd-ordercycles
1
T
R
2
T
R
3
T
R
4
T
R
T
5
Chrono-stratigraphy
Sea-levelrise
OperationalUnitsFZ a. b. c.
Gre
enh
ou
se
a. Tectonicpulses
b. Ash beds
c. Climatephase
FZ. Fusulinidzonation
R = RegressionT = Transgression
(Sea-level curve from
Ross and Ross, 2009;
Fusulinid zonation from
Wahlman, 2019)
Numerous 3rd- and higher-order cycles of sea-level change organized into larger 2nd-order trends (5 – 10+ m.y. in duration); from oldest to youngest:
WC D – lowermost WC C2
WC C2
WC C1
WC A - B
Spraberry – L. Clear Fork
1
2
3
4
5
mwu mwu: mid-Wolfcampunconformity
Stratigraphic framework,Wolfcamp - Spraberry
7500
8000
8500
9000
9500
10000
10500
Penn.
Wolfcam
p-
ian
Le
on
ard
ian
Wolfcamp D: Basinal cyclothems (starved basin)
Wolfcamp C: Clay-rich shale(progradation of Eastern Shelf deltas & Glasscock Nose)
Wolfcamp A – B: silty- and calcareous organic-rich mudstones;carbonate percentage increases upward
Spraberry – Dean:silty mudstones and clay-rich siltstones punctuated by multiple deeper-water submarine fan complexes(incl. massive to laminated, fine-grained sandstones)
Lower Strawn: shallow-water platform limestones
mid-WCunconformity
GENERAL DESCRIPTION / DEPOSITIONAL FACIES
C2
C1
A
Jo Mill
Lower
Leonard
Shale
Dean
Lower
Spraberry
Middle
Spraberry
Upper
Spraberry
UpperLeonard
Strati-graphy
WFMP
D
B
Wo
lfc
am
p
Midland Basin Type Log
(modified from Hamlin and Baumgardner, 2012)
MD(ft.)
Lower Strawn Limestone andWolfcamp D (Cline)
Mid Continent / Anadarko Basin
(Gianoutsos et al, USGS, 2014)
AAPG COSUNA chart (1985)Midland Basin
(Reed and Mazzullo, 1987)
Midland BasinFusulinid zonation
Wolfcamp
Formation
Eastern Shelf
Lower Strawn Limestone = Early Strawn
Middle & Upper Strawn =lower portion of WC D
STRAWN GROUP STRATIGRAPHY (DESMOINESIAN SERIES)
Wolf-
camp-
ian
Admiral Fm.
Putnam Fm.
Moran Fm.
Pueblo Fm.
Cisco –
Canyon
Group
Cisco Gp.
Canyon Gp.
Strawn Gp.Strawn
Gp.
Bend Gp.Bend Gp.
Virgil-ian
Miss-ourian
Pe
nn
sylv
an
ian
Des-moine-
sian
Atokan
Morro-wan
Barnett
Shale
Mississippian
Limestone
Mississippian
Limestone
Ches-terian
Mera-mec-ian
Osagean
Mis
sis
sip
pia
n
Lower Desmoinesian Facies (Lower Strawn Limestone)
• Shallow water platform carbonate facies extend across entire Midland Basin and Eastern Shelf region
• Lower Strawn Limestone is generally < 200 ft. thick in Midland Basin
(Wright, 2011)
• Core analyses indicate typical Penn shelf cyclothem deposits: burrowed skeletal wackestones grading upward into phylloid algal packstones and skeletal grainstones, capped by exposure surfaces
• Pre-dates drowning of Midland, Delaware basins
Wolfcamp D (Canyon – Cisco) facies
(Ewing, 2016)
Organic-rich Wolfcamp D (Canyon – Cisco)
black shales in core from the center of Midland Basin
(Saller et al., 1999)
Photomicrographs of
highly porous limestones
of the Horseshoe Atoll
reef complex
2 in.
• Drowning of basins and backstepping of surrounding shelfal regions
1
T
R• Silica – rich shales; relatively high clay content
thin dolomite or LS; highly correlative basin-wide
• Organic content partitioned into multiple thin cycles
Wolfcamp D: Basinal cyclothems
10
0 f
t.
0 150GR 0.2 2000Res.
L. Strawn
1040
010
500
1060
0
• Equivalent to classic “Penn. cyclothems” on shelves
non-porous, thin dolomite or LS
organic-rich, silica-rich shale
clay-rich, low TOC shale
• Each basinal cyclothem = 15 – 45 ft. thick; bounded by
• High pore pressures due to depth, maturity
Wo
lfca
mp
D
Wolfcamp C
• Westward progradation of Eastern Shelf delta systems and platform margins (100 -150 km)
Preliminary correlation of MB tops to Eastern Shelf
• Initial development of Glasscock Nose during WFMP C1 time
(Sinclair et al., 2018)
Wolfcamp C
• Uplift of CBP structural blocks and development of mid-Wolfcamp unconformity
Progradation of Wolfcamp C shelf delta systems across the Eastern Shelf
(Sinclair et al., 2017)
(Sinclair et al., 2017)
SW
Sequential development of the Glasscock Noseprograding, mounded deep-water carb. flows
Possible analog: carbonate delta drift
Indian Ocean/Maldives seismic line
(Reed, 2014)
mid-Wolfcamp unconformity on the CBP
• note diachronous nature of unconformity across Permian Basin region
• last major tectonic pulse prior to middle –late Permian subsidence phase
Wolfcamp A - B
Platform Carbonate
Shelf Edge Carbonate
Slope Sediments & Reef Talus
Carbonate Debris Flows
Carbonate Gravity Flows
Land
Clastic Detrital
Clastic Slope Sediments
Clastic Gravity Flows
Delta
Pelagic Sediments
Silt Cloud in Suspension
Anaerobic Zone
(Organic-rich Sediments)
Basinal Sediments
Wolfcamp A & B Facies Map
Schematic Block Diagram of
Wolfcamp Facies in Midland Basin
San Simon
Channel
North Basin
Platform
Glasscock
Nose
Marathon
Thrust Belt
Fluvial - Deltaic
Platform
Carbonate
Clastic
Slope
Land
Carbonate Slope
Debris
Flow
Carb
Gravity Flow
Clastic
Gravity Flow
Pelagic Sed.
Platform
Carbonate
Land
Land
CBPMidland
Basin
Marathon
Thrust Belt
North
Older
Wolfcamp
Clastics
Wolfcamp A and B Facies & Depositional Model
(Diagram by T. Reed, 2013,
based on Handford, 1981)
(Sinclair et al., 2018)
• 700+ ft. of organic-rich, silica- and calcareous-rich mudstone punctuated by numerous density flows (carb. turbiditesand debris flows)
• Aggradation of carbonate margins during second-order highstand increase percentage of CaCO3 into basin during WFMP A time
Wolfcamp A - B
• Interval currently resides in peak oil window in Midland Basin; remains a main horizontal drilling target
• Six operational sub-units:
• A1
• A2
• A3
• B1
• B2
• B3
L. Leonard Shale
Dean
Wolfcamp B
XRD analyses from core(n = 476)
• WC B are predominantly siliceous mudstones
• WC A are mixed carb-silica mudstones
Wolfcamp A
(Mzee, 2018)
Calcareous mudstone
Wolfcamp B2 Wolfcamp A3
(Murphy, 2105)
Wolfcamp carbonate debris flows
• Flows are thickest and coarsest near the shelf margins; distal portions of flows are thinner and finer grained
• Geometries include sheet-like fans and highly channelized flows
Spraberry - Dean
7500
8000
8500
9000
9500
10000
10500
Penn.
Wolfcam
p-
ian
Le
on
ard
ian
Wolfcamp D: Basinal cyclothems (starved basin)
Wolfcamp C: Clay-rich shale(progradation of Eastern Shelf deltas & Glasscock Nose)
Wolfcamp A – B: silty- and calcareous organic-rich mudstones;carbonate percentage increases upward
Spraberry – Dean:silty mudstones and clay-rich siltstones punctuated by multiple deeper-water submarine fan complexes(incl. massive to laminated, fine-grained sandstones)
Lower Strawn: shallow-water platform limestones
mid-WCunconformity
GENERAL DESCRIPTION / DEPOSITIONAL FACIES
C2
C1
A
Jo Mill
Lower
Leonard
Shale
Dean
Lower
Spraberry
Middle
Spraberry
Upper
Spraberry
UpperLeonard
Strati-graphy
WFMP
D
B
Wo
lfc
am
p
Midland Basin Type Log
(modified from Hamlin and Baumgardner, 2012)
MD(ft.)
• 1st major incursion of submarine fans
• Equivalent to 3rd Bone Spring SsDean
LowerLeonard Sh.
• organic-rich siliceous shales
Jo Mill • 2nd major incursion of submarine fans• Equivalent to 2nd Bone Spring Ss
L. Spraberry • siliceous shales, minor fans
M. Spraberry • silty, shales; minor fan complex
U. Spraberry• 2 major submarine fan complexes
(Floyd and Driver fans)• Equivalent to 1st Bone Spring Ss
whole-rockmineralogy,Dean Ss
(Mzee, 2018)
Qtz45%
Clay22%
Dolomite17%
Dean – Spraberry units of the Midland Basin
• Main facies:
• Massive f.g. sandstones (“Bouma A”)• Laminated siltstones / shales• Burrowed siltstones / shales (O2)
• Black shale (thin caps)
• Provenance? (north vs. south)Depositional model ?
• All fans (Dean, Jo Mill, Middle & Upper Spraberry) are similar in appearance
(a) Poroussandstone
(b) Sandstonecemented w/ferroandolomite
(Hamlin and Baumgardner, 2012)
Mas
sive
san
dst
on
e
Bo
um
a se
qu
en
ce Laminatedsiltstones
(Waite et al., in press)
ZIRCON U-Pb RADIOMETRIC AGE SPECTRA(DEAN – SPRABERRY, CENTRAL & SOUTHERN MIDLAND BASIN)
• Strong age signal (“peaks”)
• Grenville province (1100 Ma)
• Gondwana (600 Ma)
• Appalachia (400 Ma)
• Intermediate signal
• Granite-Rhyolite province (1400 Ma)
• Yavapai – Mazatzal province (1700 Ma)
Strong age signals are from southern-located provinces, indicating a southern source land for Dean – Spraberry sands in central & southern Midland Basin (currently accepted view: all sands were from a northern source)
• Weak signal
Gravity Flow DepositsLow Sea Level
Lowstand and ensuing transgression–• Shelf exposed
• Clastics move across shelf via wind and in wadis
• Clastic gravity flow deposits bypass shelf during
lowstand and are cannabalized during early transgression
Carbonate
Debris FlowsBasinal ShalesHigh Sea Level
Highstand –• Shelf submerged
• Carbonates on shelf
• Carbonate gravity flow deposits and organic-rich
shales in basin
Dean
N S
Wolfcamp A
Shelf Edge
L. Spraberry
Shelf EdgeM. Spraberry
Shelf Edge
Spraberry and shelf equivalents are alternating sand-rich and organic
shale/carbonate-rich packages deposited during alternating high and low sea levels.
Sands are very fine-grained turbidites with partial Bouma sequences
Organic-rich shales highly laminated and not bioturbated; Organic-poor shales bioturbated
Thin dolomitic hard grounds observed in sands and shales
Spraberry & Dean (Bone Spring) Depositional ModelEarly Permian
(based on Hanford, 1981)
Possible modern analog for Dean - Spraberry:Offshore Mauritania, African Sahara
coresample
Core data (Zuhlsdorff et al., 2008)
Summary and Conclusions
• The Wolfcamp – Spraberry interval of the Midland Basin consists of a series of lithologically- and mineralogically-complex facies; each interval is unique
• Wolfcamp A - B: Silty, calcareous terrigenous shales; carbonate % increases upward
• Dean - Spraberry: Argillaceous siltstones, punctuated by numerous submarine-fan complexes (massive & laminated sandstones)
• Wolfcamp D: basinal cyclothems
• Wolfcamp C: clay-rich shales
• Complexity of these rocks reflects changing/evolving geologic conditions (eustasy, climate, tectonics, sediment supply, biota, etc.) along the SW margin of western Pangea during Late Pennsylvanian – early Permian time
• Geologists must work closely with drilling, completion, and reservoir engineers to fully communicate the complexity and uniqueness of each unit / horizontal zone
“Not all shales are created equal”
(Hamlin and Baumgardner, 2012)