Stratigraphy and Reservoir Characteristics of the …

 

 

PSStratigraphy and Reservoir Characteristics of the Desmoinesian Granite Wash (Marmaton Group), Southern
Anadarko Basin*

Alyssa M. Karis1 and Matthew J. Pranter2

Search and Discovery Article #10813 (2015)**
Posted December 14, 2015

*Adopted from poster presentation given at AAPG Mid-Continent Section meeting in Tulsa, Oklahoma, October 4-6, 2015
**Datapages©2015 Serial rights given by author. For all other rights contact author directly.

1ConocoPhillips School of Geology and Geophysics, University of Oklahoma, Norman, OK
2ConocoPhillips School of Geology and Geophysics, University of Oklahoma, Norman, OK

Abstract

The Desmoinesian-age Granite Wash (Marmaton Group) within the southern Anadarko Basin was deposited as a series of alluvial fans, fan
deltas, and deepwater deposits derived from the Amarillo-Wichita Uplift. Deposits include stacked conglomerates, tight-gas sandstones, and
organic-rich shales that are stratigraphically complex with variable lithofacies and exhibit heterogeneous reservoir properties. The stratigraphic
and reservoir characteristics of the Marmaton Group are investigated based on cores, well logs, and XRF measurements. The deposits contain
interbedded sandstones and conglomerates of mixed lithology that commonly thin into shales basinward. Four regional flooding surfaces cap
laterally extensive organic-rich shales have been identified based on well-log signatures and mapped across the study area to establish a
stratigraphic framework. In the southern portion of the study area, the proximal deposits of the Marmaton Group exhibit frequent lithology and
lithofacies changes. XRF analyses of cuttings and cored intervals shows how elemental concentrations vary stratigraphically with lithology.
The flooding surfaces and other key surfaces that define the stratigraphic framework are used with calculated lithology and effective-porosity
logs to construct 3-D reservoir models to evaluate stratigraphic and lithological controls on reservoir heterogeneity and to illustrate
stratigraphic variability in static sandstone-body and reservoir connectivity of the Marmaton Group.

Stratigraphy and Reservoir Characteristics of the Desmoinesian
Granite Wash (Marmaton Group), Southern Anadarko Basin
Alyssa M. Karis and Matthew J. Pranter

ConocoPhillips School of Geology and Geophysics, University of Oklahoma, Norman, Oklahoma

RCML
RCML

Reservoir Characterization and
Modeling Laboratory
The University of Oklahoma

Abstract

Study Area

Type Log

GR

DPHI
NPHI

t
F

ILD

150

0.3

-0.1

0.2 2000

0

Chemostratigraphy

100

GR

t
F

0

200

Al

Ca

K

Fe

Mg

120000

0

150000

0

65000

0

80000

0

20000

0

Si
550000

The Desmoinesian Granite Wash, specifically the Marmaton Group, is a hydro-
carbon-bearing interval within the Anadarko Basin of Oklahoma and Texas that is
composed of clastic and carbonate sediments derived primarily from the Amaril-
lo-Wichita Uplift. The Marmaton Group, located in Beckham County, Oklahoma
and Wheeler County, Texas, includes a series of vertically stacked conglomerates
and tight-gas sandstones and shales that exhibit a complex stratigraphic architec-
ture, highly variable lithologies, and correspondingly heterogeneous reservoir
properties.

The stratigraphic and reservoir characteristics of the Marmaton Group, are estab-
lished based on cores, x-ray fluorescence (XRF) measurements, and well-log sig-
natures. The Marmaton Group in the southern Anadarko Basin contains interbed-
ded arkosic sandstones and conglomerates that thin laterally into shales to the
north (basinward). At least four regional, correlatable flooding surfaces (and asso-
ciated organic-rich shales) subdivide the Marmaton Group and are thought to be
self-sourcing in this liquids-rich interval. Porosity in this interval varies from 2-18%
with low permeabilities on the order of 10 μD.

Proximal to the Amarillo-Wichita Uplift, the Marmaton Group is highly lithologically
heterogeneous. XRF analyses of cored intervals show that elemental concentra-
tions vary stratigraphically in conjunction with lithology. Characteristic well-log sig-
natures correspond to different intervals and can be correlated laterally through
the study area. Cluster analysis implemented on well-log data resulted in a 63%
correlation to the Mayfield 1-34 core description but achieved low correlations for
the Mayfield 1-2 (0%) and Sage 1-34H (53%). Well-log cutoffs performed on
well-log data have a 74% correspondence rate to Mayfield 1-34 core description.
Overall the well-log cutoff lithologies provides an approximation of lithologies in
non-cored: 62% sandstone, 23% conglomerate, and 15% shale. A compiled lithol-
ogy model of the Marmaton Group displays spatial patterns by zone constrained
to the vertical lithology proportion trend, vertical variograms, horizontal vario-
grams, and lithology percentages. Using the lithological trends as an input, effec-
tive porosity and water saturation show that conglomerates on average have a
higher effective porosity (by 1%) lower water saturation (by 1%) throughout the
Marmaton Group.

Research Objectives
This study characterizes the Marmaton group in the Desmoinesian Granite Wash as
well as the reservoirs within the group. In order to properly assess the attributes
within this interval, the following objectives are explored:
1) Determine the key lithologies, petrophysical properties, and unique well-log signa-
tures or values associated with certain lithologies or petrophysical properties.
2) Define the structural and stratigraphic framework of the Marmaton Group through-
out the region.
3) Map the spatial distribution of lithology, porosity, and water saturation.

103°

37°

CIMARRON

DALHART

BASIN

DALLAM

102°

101°

CIMARRON ARCH

100°
ANADARKO
SHELF /
RAMP

TEXAS

BEAVER

HARPER

WOODS

ALFALFA

GRANT

99°

98°

97°

KAY

CHEROKEE
PLATFORM

NOWATA

C R A I G

96°

N
O
T
G
N

I

H
S
A
W

NOBLE

NEMAHA
UPLIFT

PAYNE

O S A G E

R O G E R S

M AY E S

PAWNEE

T U L S A

95°

OTTAWA

37°

E
R
A
W
A
L
E
D

OZARK
UPLIFT

36°

A D A I R

S E Q U O YA H

SHERMAN

HANSFORD

OCHILTREE

LIPSCOMB

WOODWARD

GARFIELD

MAJOR

ELLIS

ROGER
MILLS

36°

HARTLEY

MOORE

HUTCHINSON

ROBERTS

HEMPHILL

BRAVO
DOME

OLDHAM

35°

DEAFSMITH

POTTER

CARSON

GRAY

AMARILLO

M

ountain

WHEELER

RANDALL

ARMSTRONG

DONLEY

PALO DURO BASIN

PARMER

CASTRO

SWISHER

BRISCOE

HALL

CHILDRESS

103°

102°

101°

100°

United
States Oklahoma

DEWEY

BLAINE

KINGFISHER

LOGAN

CREEK

WAGONER

CHEROKEE

ANADARKO BASIN

CUSTER

LINCOLN

OKMULGEE

MUSKOGEE

CANADIAN

OKLAHOMA

POTTAWATOMIE

OKFUSKEE

COLLINGSWORTH

KIOWA

View
ewewewewww

BECKHAM
BECKHAM

Fault System
WICHITA
HOLLIS-HARDEMAN

JACKSON

HARMON

GREER

WASHITA

CLEVELAND

CADDO

GRADY

N

I

A
L
C
c
M

Meers Fault

UPLIFT

COMANCHE

TILLMAN

COTTON

M

BASIN
99°

STEPHENS

A

R

D

M

O

R

E

A
RIE
T
TA

GARVIN

ARBUCKLE
UPLIFT

MURRAY

PONTOTOC

CARTER

JOHNSTON

BASIN

MARSHALL

34°

JEFFERSON

LOVE

BASIN

98°

E
L
O
N

I

M
E
S

HUGHES

McINTOSH

ARKOMA BASIN

H A S K E L L

P ITTSBURG

L AT I M E R

L E F L O R E

35°

COAL

P U S H M ATA H A

ATOKA

OUACHITA
UPLIFT

C H O C TAW

M c C U RTA I N

34°

N

50 miles
80 Kilometers

97°

BRYAN

96°

95°

Map of tectonic provinces for Oklahoma and Texas. The study area is shown in red (modified
from Johnson and Luza, 2008; Northcutt and Campbell, 1995; Campbell, et al., 1988; Dutton,
1984; LoCricchio, 2012; McConnell, 1989).

AA

B

TX

OK

Wheeler

Roger Mills

Model Area

B’

Beckham

Wells with digital and/or raster logs

N

A’

4 mi
6.4 km

11N 26W

11N 25W

N

10N 26W

10N 25W

Regional extent map of this study. The area encompasses parts of Wheeler
County, Texas, Roger Mills County, Oklahoma and Beckham County,
Oklahoma. Within the defined limits there are: 430 wells in total, 353 wells
with digital well-logs, 77 wells with raster well-logs, 19 horizontal wells, and
3 wells with cored intervals (star=Mayfield 1-34, triangle= Sage 1-34H, and
square=Mayfield 1-2). Lines A-A’ and B-B’ are regional cross-sections that are
examined later.

Wells with digital logs

3 mi
4.8 km

Zoomed in view of the model area situated in
Beckham County. It lies in front of the Mountain View
Fault system in the Mayfield West vicinity. There are
60 wells that have the following digital well-logs:
gamma ray, deep resistivity, neutron porosity, and
density porosity.

Marmaton Wash

Marmaton A

Marmaton B

Marmaton C

Marmaton D

Marmaton E

Marmaton F

0
0
4
2
1

0
0
5
2
1

0
0
6
2
1

0
0
7
2
1

0
0
8
2
1

0
0
9
2
1

0
0
0
3
1

0
0
1
3
1

0
0
2
3
1

0
0
3
3
1

0
0
4
3
1

0
0
5
3
1

0
0
6
3
1

0
0
7
3
1

0
0
8
3
1

0
6
6
3
1

5
6
6
3
1

0
7
6
3
1

5
7
6
3
1

0
8
6
3
1

5
8
6
3
1

0
9
6
3
1

5
9
6
3
1

Type log from the Mayfield 1-34 (API
35009202830000) wire-line logs with formation
tops (for location refer to Figure 2). The green
box encapsulates the 40 ft (12.2 m) of core de-
scribed and used in this study.

Concentrations of the six major light elements (Al, Ca, K, Fe, Mg, and
Si), vary throughout the Mayfield 1-34 cored interval and through the
different lithologies. The trends for Al and K mimic each other sug-
gesting they are linked (perhaps by potassium feldspar concentra-
tions). Low Si values coincide with the start of the shale lithology.
Transitions between sandstone and conglomerate lithologies is often
marked by a decrease followed by a sharp increase in light element
concentration.

Geologic Setting

N

q

E

A

m

Study Area

arillo-Wichita

plift

U

O u a c h i t a s

0

0

mi
km

600

966

B

Sea
Level

10,000ft
3,000 m

A

WICHITA
MTNS.

ANDARKO BASIN

Permian

Shawnee
Cottage Grove
Hogshooter
Checkerboard Marmaton

Skinner
Atoka

Upper
Morrow

n

n i a

n

a

y lv

s

n

n

e

P

pia
M is sis sip
Sil D e v.

n

b ria

m

P r e c a

n

Late Cambrian-Ordovician

dle C
arly Mid

bria
m
a

E

0 50 100 Miles

0 60 160 Km

h

c
r
A
m
C

i

B

a
h
a
m
e
N

t
f
i
l

p
U

W

A
ic
hita

M

ts.

MAJOR LITHOLOGIES

Sandstone and shale

Conglomerate (”granite wash”)

Salt, anhydrite, and shale

Black shale

Limestone and dolomite

Rhyolite, granite and gabbro

Shale, limestone and sandstone

Granite and rhyolite

Sea
Level

10,000ft
3,000m

20,000ft
6,000m

30,000ft
9,000m

40,000ft
12,000m

Middle Pennsylvanian (308 Ma) pa-
leogeographic map (modified from
Blakey, 2013). The building of the
Amarillo-Wichita uplift started prior in
the Early Pennsylvanian and contin-
ues through to the end of the Penn-
sylvanian. Even though the mountain
range is still undergoing positive
uplift, there is still a stark contrast be-
tween the elevation between the
mountains and Anadarko Basin. The
study area is located just south of the
Equator.

MOUNTAIN FED
ALLUVIAL FANS &
FAN DELTAS

AVALANCHING
INERTIA FLOW
TURBIDITY FLOW

SE-NW structural cross section
of the Anadarko Basin. Adjacent
to the Amarillo-Wichita uplift is
the deepest part of the basin,
producing a significant asymme-
try. Accommodation space juxta-
posed to the uplift allowed for a
large sediment accumulation
(after Johnson, 1989; Dutton and
Garnett, 19889; Pippin, 1970).

NARROW
SHELF

Surface Plume

HUMMOCKY
LOBES
& SPLAYS

a l

xi m

P r o

TALUS

Distal

BASIN PLAIN

Cartoon for the environment of
deposition. The mountains are
analogous to the Amarillo-Wichita
uplift. Coarse proximal deposits
belong to alluvial fan and fan delta
systems. Distal submarine fan lobes
contain finer grains. This study
focuses on proximal deposits that
span grain sizes of cobbles to mud
(modified from Reading and
Richards, 1994).

Sys

Series

Group

Unit

Vigilian

Shawnee
/Cisco

Shawnee Wash

Heeber Sh

Douglas
/Cisco
Lansing
/Hoxbar

Kansas City
/Hoxbar

Marmaton

Missourian

n
a
i
n
a
v
l
y
s
n
n
e
P

Desmoinesian

Cherokee

Atokan

Atoka

Morrowan

Morrow

Haskell Sh

Tonkawa Ss

Cottage Grove
Wash

Hoxbar Wash
/Sh
Hogshooter
Wash
Checkerboard
Wash
Cleveland
Wash

Marmaton
Wash

Upper Skinner
Sh
Upper Skinner
Wash
Lower Skinner
Sh
Lower Skinner
Wash
Redfork Ss&
Sh

AtokaWash
13 Finger Ls

Upper Morrow
Squawbelly Ls
Lower Morrow

Stratigraphic column for the Oklahoma
Granite Wash (modified from Mitchell,
2011). The Marmaton zones are based on
shale breaks and regional flooding surfaces
throughout the study area. The Desmoine-
sian Granite Wash has different nomencla-
ture in different states and petroleum com-
panies. In order to draw comparisons to
other literature, the following is a guide for
the nomenclature adopted in this study.
Seven intervals of the Marmaton Group has
been divided into (Wash, A-F) and their
equivalents are as follows: Marmaton B =
Carr, Marmaton C = Caldwell/Britt, Marma-
ton D = Granite Wash A, Marmaton E =
Granite Wash B, and Marmaton F = Granite
Wash C.

Marmaton Wash
Marmaton A
Marmaton B
Marmaton C
Marmaton D
Marmaton E
Marmaton F

A

C

E

10

1

0.1

0.01

0.001

)
d
m

(

y
t
i
l
i
b
a
e
m
r
e
P

0.0001

0

Core Description

Lithology Estimation

1 in
2.54 cm
GR
GR

100
100

NPHI
NPHI
DPHI
DPHI

ILD
ILD
200 0.3 -0.1 0.2 200
200 0.3 -0.1 0.2 200

1 in
2.54 cm
GR

100

NPHI
DPHI

ILD
200 0.3 -0.1 0.2 200

B

D

A) Typical
closed-framework
conglomerate found
throughout the core
and has large varia-
tion of grain size. Low
GR and ILD. DPHI is
consistently higher in
value than NPHI.

C) Massive medium
grained sandstone
with fine, dark grey
layers of silt
throughout.

B) The dark grey, matrix-sup-
ported conglomerate, has higher
GR, ILD compared to the
closed-framework conglomer-
ate. The NPHI values cross-over
with the DPHI values frequently.
In well-log curves, this open
framework conglomerate ap-
pears to be closer to a sand-
stone signature.

D) Black shale break in the cored
interval that has a very high GR
signature and NPHI values great-
er than DPHI values. Core photo-
graphs courtesy of OPIC.

A

)

.

m
m
h
o
(

D
L
I

70

60

50

40

30

20

10

B

70

60

50

40

30

20

10

)

.

m
m
h
o
(

D
L
I

C

)
v
/
v
(

I

H
P
N

0.24

0.20

0.16

0.12

0.08

0.04

Key

Conglomerate data point

Conglomerate seed point

Sandstone data point

Sandstone seed point

Shale data point

Shale seed point

0.05

0.10

0.15

0.20

110

120

130

140

150 160

NPHI (v/v)

GR (API)

60

80

100 120 140 160

GR (API)

Cross plots of A: NPHI vs. ILD, B: GR vs. ILD, and C: GR vs. NPHI. Using the 40 ft
(12.2 m) of core from the Mayfield 1-34 well, k-mean algorithm cluster analysis
was performed to establish electrofacies. Three logs were used: GR, ILD, and
NPHI. The data points have been classified into three clusters: conglomerate,
sandstone, and shale. Overall, the three cross-plots show tighter cluster groupings
for conglomerate and sandstone compared to the spread out data distribution for
shale.

1 in
2.54 cm
GR

100

NPHI
DPHI

ILD
200 0.3 -0.1 0.2 200

1 in
2.54 cm
GR

100

NPHI
DPHI

ILD
200 0.3 -0.1 0.2 200

E) Porosity-permeability cross plot for the Mayfield 1-2, Mayfield
1-34, and Sage 1-34H wells. Conglomerate has a cluster of data
points with porosity between 4 and 8% with permeabilities of
0.2-4 md. Most sandstone data points lie between 5 and 10%
porosity with greatly varying permeability (between 3×10-4 and 8
md). Shale, as expected have low, porosities (4-6%) and perme-
abilities (0.2-0.4 md).

Conglomerate

Sandstone

Shale

15

20

5

10
Porosity (%)

Cluster

# Data
Points

NPHI (V/V)

GR (API)

ILD (ohm.m)

Mean Std Dev. Mean Std Dev. Mean

Std
Dev.

Conglomerate

41

0.0552

0.01

111.7

6.128

14.619 1.161

Sandstone

28

0.06325 0.01978 126.06

6.135

44.003 9.432

14

0.17007 0.04548 154.67

6.852

41.318 15.13

Shale

Zone

Wash

A

B

C

D

E

F

Shale

GR (cid:2) 105

GR (cid:2) 105

GR (cid:2) 105

GR (cid:2) 110

GR (cid:2) 120

GR (cid:2) 125

GR (cid:2) 135

Sandstone

RHOB > 2.52

RHOB > 2.57

RHOB > 2.55

RHOB > 2.52

RHOB > 2.52

RHOB > 2.52

RHOB > 2.56

Conglomerate

RHOB (cid:3) 2.52

RHOB (cid:3) 2.57

RHOB (cid:3) 2.55

RHOB (cid:3) 2.52

RHOB (cid:3) 2.52

RHOB (cid:3) 2.52

RHOB (cid:3) 2.56

Distribution of data points for the
k-means cluster analysis.

Wire-line values used to define vari-
ous lithologies.

Lithology Estimation

GR

t
F

200

Core
Lithologies

100

Electrofacies
Lithologies

Cutoff
Lithologies

7.1823 in

0
6
6
3
1

5
6
6
3
1

0
7
6
3
1

5
7
6
3
1

0
8
6
3
1

5
8
6
3
1

0
9
6
3
1

5
9
6
3
1

GR, core lithologies, electrofacies lithologies, and cutoff lithologies for
the Mayfield 1-34 well. The electrofacies do not capture thin beds.
There is also a predicted sandstone package immediately following
the shale lithology in the electrofacies that is not seen in core. It is de-
scribed as a conglomerate containing mostly pebble sized clasts,
which the algorithm classified as a very coarse sandstone. That mis-
match of predicted electrofacies lithologies and actual lithologies is
seen to the bottom in the cored interval. The cutoff lithologies do not
show the thin conglomerate around 3,667 ft [4,166 m] as well. It does
decipher between the conglomerate and sandstones lithologies simi-
larly to the physical description of the core. Overall, the cutoff predict-
ed lithologies match the core lithologies better than the electrofacies
predicted lithologies (74% and 63% respectively).

Structural and Stratigraphic Framework
Structural and Stratigraphic Framework

Depth (ft)
11200

A

TX

State Line

OK

A’

Depth (ft)
12000

B

Marmaton Wash
Marmaton A
Marmaton B

Marmaton C

Marmaton D

13200

Marmaton E

Marmaton F

12200

12400

12600

12800

13000

13400

13600

13800

14000

14200

GR

0

150

Zones
Marmaton
Wash
Marmaton A

Marmaton B

Marmaton C

Marmaton D

Marmaton E

Marmaton F

Zones
Marmaton
Wash
Marmaton A

Marmaton B

Marmaton C

Marmaton D

Marmaton E

Marmaton F

V.E. 1x

V.E. 5x

Lithology

-Conglomerate

-Sandstone

-Shale

V.E. 5x

B’

Marmaton Wash

Marmaton A

Marmaton B

Marmaton C

Marmaton D

Marmaton E

Marmaton F

Lithology Proportion (fraction)

0.2

0.4

0.6

0.8

0

0

1

Wash

Lithology Proportion (fraction)

0.2

0.4

0.6

0.8

1

A

0

0

Wash

C

B

74.0781 in

Wells used for modeling with the
KB service and unexaggerated
model. 56 vertical and 4 horizon-
tal wells were used as guides for
the modeling.

The exaggerated model grid
shows in greater detail changes
in zone thicknesses. The model
grid dimensions are approxi-
mately 11.9 mi x 8.33 mi x 0.49
mi (19.2 km x 13.4 km x 0.79 km)
for a total of 47.2×106 cells.

r
e
y
a
L

100

200

300

400

500

600

700

800

900

1000

0

0.2

0.4

0.6

0.8

1

MFS

MFS

MFS

A

B

C

D

E

F

MFS

Vertical proportion curve of the
three different upscaled mod-
eled lithologies by layer and
zone. Orange is conglomerate,
yellow is sandstone, and grey is
shale. MFS stands for marine
flooding surface which show up
as high GR, high NPHI, and low
DPHI readings on wire-line logs.
There are pulses of conglomer-
ate followed by shale caps, indi-
cating a cyclic deposition con-
trolled by relative rise and fall of
sea level.

r
e
y
a
L

100

200

300

400

500

600

700

800

900

1000

A

B

C

D

E

F

Spatial Distribution of Lithology and Petrophysical Properties

The following SIS lithology model was constructed using the following parameters:
1) Upscaled well logs
2) Histogram of lithology percentages
3) Vertical and horizontal variograms (by zone and lithology). Due to the different type of deposition for each rock type the following assumptions
were made:

4) Vertical lithology proportion curve

– Conglomerate and sandstone have relatively longer vertical ranges to shale
– Shale has relatively longer horizontal ranges compared to conglomerate and sandstone

This structural cross section (refer to regional map for location)
has equally spaced wells that are not to scale. Structure elevation
decreases to the southeast and zones have much higher GR
readings. The red lines denote possible regional reverse faults
with displacements of 600 ft (183 m).

This structural cross section of the Marmaton Group (refer to re-
gional map for location) has equally spaced wells that are not to
scale. Generally, the structural elevation of the formation tops in-
crease going south and zones Wash-F increase in thickness. The
red lines denote possible reverse faults shows possible reverse
faulting as well, with displacements of 50-400 ft (15-122 m).

A

Structure map for the top of the Marmaton Group

Isopach map for the Marmaton Group

B

N

N

Wheeler

Wheeler

Roger
Mills

Roger
Mills

Beckham

Thickness
(ft)
– 1900

– 1700

– 1500

– 1300

– 1100

– 900

– 700

– 500

0
0

mi
km

4
6.4

Beckham

0
0

mi
km

4
6.4

Structure map for the top of the Marmaton Group shows a trend of
increasing structural elevation to the northwest. The deepest ele-
vations occur on the county border between Beckham and Roger
Mills counties which coincides with the axis of the basin. The red
dashed lines are possible faults within the study area.

The isopach map for the Marmaton Group shows patterns of thick
and thin deposits that line up with the interpreted faults. The thin
syndepositional deposits correspond to the up-thrown side of the
reverse faults, while thick syndepositional deposits correspond to
the down-thrown side. Thicker sediment accumulations occur
along the southern boundary of the study area, which coincides
with the Amarillo-Wichita uplift.

(cid:2)(cid:3)e
– 0.14
– 0.12
– 0.10
– 0.08
– 0.06
– 0.04
– 0.02
– 0.00

V.E. 5x

0

0

mi

2

km 3.22

N

0

0

mi

2

km 3.22

N

Lithology distribution throughout the whole model is as fol-
lows: 59% sandstone, 23% conglomerate, and 18% shale.
Shale deposits appear as more laterally continuous de-
posits throughout the layers, while the sandstone is more
channelized as expected with the associated fan delta de-
posits. Conglomerate deposit patterns depend on where in
the cycle the system is. During high conglomerate deposi-
tion, it blankets the layers, where as in periods of de-
creased sediment input, channelized flows can be seen.

A layer from the Marmaton F zone where
conglomerate and sandstone deposits
are dominant (k slice 880). The sand-
stone deposits are interpreted to form
channels in the north by northeast direc-
tion (arrows) while the conglomerate de-
posits are more laterally connected
trending in the northeast direction.

Shale is the dominate lithology in this
layer (k slice 587) and appears very con-
tinuous with no apparent depositional
trend azimuth. The sandstone bodies are
too disconnected to decipher an azimuth.

The next phase of the research was to model petrophysical properties (SGS). Four sets of equations used to figure out the important petro-
physical properties of effective porosity and water saturation:
1) (cid:2)(cid:3)(cid:4)(cid:3)(cid:5)(cid:6)(cid:7)(cid:8)(cid:7)(cid:9)(cid:7)(cid:10)(cid:11)(cid:12)(cid:13)(cid:14)(cid:15)(cid:16)(cid:7)(cid:17)(cid:7)(cid:18)(cid:12)(cid:13)(cid:14)(cid:15)(cid:16)(cid:19)(cid:7)(cid:7)(cid:20)(cid:20)(cid:21)(cid:22)(cid:23)(cid:21)(cid:24)(cid:3)(cid:7)(cid:25)(cid:4)(cid:26)(cid:7)(cid:27)(cid:28)(cid:5)(cid:6)(cid:21)(cid:7)(cid:6)(cid:29)(cid:3)(cid:28)(cid:4)(cid:6)(cid:4)(cid:30)(cid:29)(cid:21)(cid:27)(cid:7)(cid:29)(cid:31)(cid:7)!(cid:28)(cid:29)(cid:23)(cid:28)(cid:7)(cid:23)(cid:5)(cid:27)(cid:21)(cid:7)(cid:2)(cid:3)(cid:4)(cid:3)(cid:5)(cid:6)(cid:7)(cid:8)(cid:7)(cid:18)(cid:12)(cid:13)(cid:14)(cid:20)(cid:20)
(cid:16)(cid:19)(cid:7)”(cid:27)(cid:28)(cid:5)(cid:6)(cid:21)(cid:7)(cid:8)(cid:7)(cid:10)#$(cid:6)(cid:4)(cid:30)(cid:7)&(cid:7)#$(cid:27)(cid:5)(cid:31)’(cid:19)(cid:7)*(cid:7)(cid:10)#$(cid:27)(cid:28)(cid:5)(cid:6)(cid:21)(cid:7)&(cid:7)#$(cid:27)(cid:5)(cid:31)’(cid:19)(cid:7)**GRshale and GRsand were picked from the highest and lowest values of GR per zone
(respectively.**
3) (cid:2)(cid:21)(cid:25)(cid:25)(cid:21)(cid:23)(cid:3)(cid:29)/(cid:21)(cid:7)(cid:8)(cid:7)(cid:2)(cid:3)(cid:4)(cid:3)(cid:5)(cid:6)(cid:7)&(cid:7)(cid:10)”(cid:27)(cid:28)(cid:5)(cid:6)(cid:21)(cid:7)(cid:20)(cid:7)(cid:5)/(cid:21)(cid:26)(cid:5)(cid:30)(cid:21)(cid:7)(cid:27)(cid:28)(cid:5)(cid:6)(cid:21)(cid:7)(cid:2)(cid:19)(cid:7)(cid:7)** average shale porosity was picked per zone**
;(cid:19)(cid:7)*(cid:31)(cid:19)(cid:7)(cid:7)**assuming ideal Archie equation and m and Rw picked from Pickett plot**

Left: The entire effective porosity
model. Shale lithologies were given a
value of zero, thus the effective porosi-
ties for conglomerates and sandstones
are highlighted throughout. Right: The
water saturation model also assigned a
universal value to shales: 100%. Again,
this allows for the focus of analyses to
be on the conglomerates and sand-
stones.

Sw %
-100
-80
-60
-40
-20
-0

V.E. 5x

0

0.2

0.4

0.6

0.8

1

Lithology

-Conglomerate

-Sandstone

-Shale

0

0

mi

5

km 8.05

(cid:2)(cid:3)e
– 0.14
– 0.12
– 0.10
– 0.08
– 0.06
– 0.04
– 0.02
– 0.00

0

0

mi

5

km 8.05

Sw %
-100
-80
-60
-40
-20
-0

0

0

mi

5

km 8.05

Comparisons between A) lithology, B) effective porosity, and C) water saturation models. Layers 880 and 379 show times of
maximum regression, thus high percentages of sandstone and conglomerate. In these slices there are higher effective porosi-
ties and lower water saturations. Layers 587 and 147 show points of maximum transgression, thus shales dominate. This
drives down the average effective porosity closer to 0 and water saturation up to 100%. Overall, conglomerate has a higher
effective porosity and lower water saturation than sandstone on average (5.7% vs. 4.5% and 11.7% vs. 13.5%, respectively.
The highest effective porosities for conglomerate and sandstone were 6.7% and 5.1%, respectively and the lowest water sat-
urations for conglomerate and sandstone were 9.47% and 9.93%, respectively.

Conclusions

The Desmoinesian Granite Wash, specifically the Marmaton Group, is a hydrocarbon-bearing interval within the Anadarko Basin of Oklahoma
and Texas that is composed of clastic and carbonate sediments derived primarily from the Amarillo-Wichita Uplift. The Marmaton Group, locat-
ed in Beckham County, Oklahoma and Wheeler County, Texas, includes a series of vertically stacked conglomerates and tight-gas sandstones
and shales that exhibit a complex stratigraphic architecture, highly variable lithologies, and correspondingly heterogeneous reservoir proper-
ties.

The stratigraphic and reservoir characteristics of the Marmaton Group, are established based on cores, x-ray fluorescence (XRF) measure-
ments, and well-log signatures. The Marmaton Group in the southern Anadarko Basin contains interbedded arkosic sandstones and conglom-
erates that thin laterally into shales to the north (basinward). At least four regional, correlatable flooding surfaces (and associated organic-rich
shales) subdivide the Marmaton Group and are thought to be self-sourcing in this liquids-rich interval.

Proximal to the Amarillo-Wichita uplift, the Marmaton Group is highly lithologically heterogeneous. XRF analyses of cored intervals show that
elemental concentrations vary stratigraphically in conjunction with lithology. XRF measurements show that concentrations of potassium and
aluminum have the same increasing and decreasing trends suggesting that they may be associated (in minerals such as potassium feldspar).
Characteristic well-log signatures correspond to different intervals and can be correlated laterally through the study area. Cluster analysis im-
plemented on well-log data resulted in a 63% correlation to the Mayfield 1-34 core description but achieved low correlations for the Mayfield
1-2 (0%) and Sage 1-34H (53%). Well-log cutoffs performed on well-log data have a 74% correspondence rate to Mayfield 1-34 core descrip-
tion. Overall the well-log cutoff lithologies provides an approximation of lithologies in non-cored: 62% sandstone, 23% conglomerate, and 15%
shale.

A compiled lithology model of the Marmaton Group displays spatial patterns by zone constrained to the vertical lithology proportion trend, verti-
cal variograms, horizontal variograms, and lithology percentages. Sandstone and conglomerate deposits appear to have a dendritic channel
(cid:3)(cid:26)(cid:21)(cid:31)’(cid:7)(cid:24)(cid:21)(cid:26)(cid:24)(cid:21)(cid:31)’(cid:29)(cid:23)?(cid:6)(cid:5)(cid:26)*(cid:27)?@&(cid:24)(cid:21)(cid:26)(cid:24)(cid:21)(cid:31)’(cid:29)(cid:23)?(cid:6)(cid:5)(cid:26)(cid:7)(cid:3)(cid:4)(cid:7)(cid:3)(cid:28)(cid:21)(cid:7)J=(cid:5)(cid:26)(cid:29)(cid:6)(cid:6)(cid:4)&Q(cid:29)(cid:23)(cid:28)(cid:29)(cid:3)(cid:5)(cid:7)?(cid:24)(cid:6)(cid:29)(cid:25)(cid:3)Y(cid:7)<(cid:28)(cid:5)(cid:6)(cid:21)(cid:7)’(cid:21)(cid:24)(cid:4)(cid:27)(cid:29)(cid:3)(cid:27)(cid:7)’(cid:29)(cid:27)(cid:24)(cid:6)(cid:5)Z(cid:7)(cid:5)(cid:7)=(cid:4)(cid:26)(cid:21)(cid:7)(cid:6)(cid:5)(cid:3)(cid:21)(cid:26)(cid:5)(cid:6)(cid:6)Z(cid:7)(cid:23)(cid:4)(cid:31)(cid:3)(cid:29)(cid:31)?(cid:4)?(cid:27)(cid:7)/(cid:21)(cid:26)(cid:3)(cid:29)(cid:23)(cid:5)(cid:6)(cid:6)Z(cid:7)’(cid:29)(cid:27)(cid:23)(cid:4)(cid:31)(cid:3)(cid:29)(cid:31)?- ous trend with no discernable depositional azimuth trend. Using the lithological trends as an input, effective porosity and water saturation show that conglomerates on average have a higher effective porosity (by 1%) lower water saturation (by 1%) throughout the Marmaton Group. Acknowledgements I would like to thank the sponsors for the Granite Wash Consortium and the Reservoir Characterization and Modeling Laboratory. I also want to acknowledge the help and guidance from Deepak Devegowda, Doug Elmore, Mark Sitton, Phil Byrd, Amy Close, Suriamin, and John Mitchell. 11400 11600 11800 12000 12200 12400 12600 12800 13000 13200 13400 13600 13800 14000 14200 Depth (ft) - 8000 - 8500 - 9000 - 9500 - 10000 - 10500 - 11000