Comparison of Mesozoic and Cenozoic Source Rock Characteristics Puale Bay Outcrops and NAS COST 1 Well Alaska Peninsula – North Aleutian Basin
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Comparison of Mesozoic and Cenozoic
Source Rock Characteristics
Puale Bay Outcrops and NAS COST 1 Well
Alaska Peninsula – North Aleutian Basin
Author(s) and affiliations:
Paul L. Decker
Alaska Division of Oil & Gas
Date presented:
March 27, 2008
Presentation Forum:
DNR Spring Technical Review Meeting, BP Energy Center
Acknowledgments of any external funding sources and in-kind contributors:
Field work and analyses for this study were conducted during 2004, 2005, and 2007 with funding
from multiple sources, including a U.S. Department of Energy grant from the Arctic Energy
Technology Development Laboratory at the University of Alaska Fairbanks to Rocky Reifenstuhl
(program head) and Paul McCarthy (principal investigator, UAF); Bristol Bay Native Corporation;
and Division of Geological & Geophysical Surveys and Division of Oil and Gas operating and
capital improvement project budgets. Field samples were collected by Rocky Reifenstuhl, Robert
Gillis, Emily Finzel, and Karen Clautice (DGGS); the author, David Shafer, and Timothy Ryherd,
(DOG); Michael Whalen (UAF); and Robert Blodgett (consulting geologist).
Cs
Cs
CsCs
CsIs
Puale
BayN o r t h A l e u t i a n /
NAS
COST 1
Alaska Peninsula
Stratigraphic Column
• Upper Triassic Kamishak Fm- Shallow Marine carbonate
• Middle Jurassic Kialagvik Fm
(Tuxedni Gp equivalent)
- Marine-nonmarine? sh-slts-ss
• Miocene Bear Lake Fm
• Eocene-Oligocene Stepovak Fm
• Paleocene-Eocene Tolstoi Fm
- Nonmarine (coaly) to shallow marine
Puale Bay outcrops
NAS COST 1 well
07RR027-038
07BG225-233(SE-NW)
07PD183-188 (SE-NW)
05EF100-103 (NW-SE)
05RR208-210 (SE-NW)
07PD191-194 (W-E)
07RR041-042 (W-E)
07BG237,07MW005
07RB11
07PD181-182
07MW003-004
07RB04-08 05RR211-213 (S-N)
05EF105
07PD195-199 (E-W)
07RR043-047 (E-W)
Puale Bay Sample Locations
Kamishak Fm (n=38)
Kialagvik Fm (n = 39)
lower Kamishak Fm biostromal facies
micritic-fossiliferous faciesbasal unconformity
Pv?
Trk
angular
unconformity
minor
fault (?)
U D
Upper Triassic Kamishak Fm Outcrops Puale Bay
upper contact, rusty ss-siltstone
carbonaceous
ss, thin coals
upward coarsening slts-ss
middle Kialagvik Fm
Js
Jk
Q
Jk
Middle Jurassic Kialagvik Fm Outcrops Puale Bay
dark gray fissile slts
lower Kialagvik Fm
Modified Van
Krevelen Diagram
Mesozoic
Units
Puale Bay
outcrops
Oil-prone Type I-II
kerogens
A A’Quaternary
Bear Lake Fm
Unga equivStepovak Fm
Tolstoi
Fm
Mz?
Mz?Mz?
Tolstoi
Fm?
MMS-75-17-36
(~52 mi long)
Milky River Fm A
A’
B
B’
50 mi
N Aleutian
COST #1
B’BQuaternary
Milky River Fm
Bear Lake Fm
Unga equiv
Stepovak FmMz?
Mz?
Mz?
Tolstoi
Fm?
Mz?
Mz?
Mz?
Tolstoi
Fm?
Bear Lake Fm
Black Hills Uplift
(transpressional margin)
N Aleutian/
Bristol Bay
Basin
MMS-75-17-09
(~155 mi shown)A TA T
A T?
A T
North Aleutian Basin
Modified Van
Krevelen Diagram
Cenozoic
Units
NAS COST 1 well
• 420 Rock-Eval/TOC
analyses
anomalous coaly kerogens
highly anomalous
coaly kerogens
Oil-Prone Coals??
• Pyrolysis can overestimate
HC liquid-generation potential
of coaly source rocks
• Kerogen microscopy and
H/C, O/C atomic ratios data
Modified Van
Krevelen Diagram
Mesozoic
and Cenozoic
Units
Puale Bay and
NAS COST 1
Hydrogen Index, mg
0
100
200
300
400
500
600
700
800
900
0.10 1.00 10.00 100.00
Hyd
roge
n In
de
x, m
g/g
TOC, %
Milky River-COST 1
Bear Lake-outcrop
Bear Lake-COST 1
Stepovak-COST 1
Tolstoi-COST 1
Kialagvik coal
Kialagvik silty mudst
Kamishak-outcrop
lean gas-prone
good-excellent gas-prone shales, carbonates
good-excellent mixed oil- & gas-prone
shales, carbonates
Type II oil-prone shales, carbonates
“oil shales”, oil-prone cannel & boghead
coals, tasmanites, etc..
dry gas-prone
potentially mixed oil- & gas-or condensate-prone (?)
non-source or
overmature
carbonaceous shales
carbonaceous shales
coals
lean oil-prone
Type I oil-prone shales, carbonates
coals
non-source or overmature
Hydrogen Index vs TOCH
ydro
gen
Ind
ex, m
g/g
TOC, %
Type and Quantity
of Organic Matter
0.00
50.00
100.00
150.00
200.00
250.00
300.00
0.00 20.00 40.00 60.00 80.00 100.00
S2, m
g/g
TOC, %
Kamishak
Kialagvik silty mudst
Kialagvik coal
Tolstoi-COST 1
Stepovak-COST 1
Bear Lake-COST 1
Bear Lake-outcrop
Milky River-COST 1
Bear Lake outcrop -- coals only y = 5.942x - 221.9
Pyrolyzed HC (S2) vs TOCTrue Average
Hydrogen Index
Full Data
Range
(coals)
y = 7.4478x - 2.663
y = 6.5359x - 3.1453
y = 3.1936x - 3.6462
y = 1.6664x - 1.0885
y = 1.2263x - 0.7252
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
50.00
0.00 5.00 10.00 15.00 20.00
S2, m
g/g
TOC, %
Kamishak
Kialagvik silty mudst
Tolstoi-COST 1
Stepovak-COST 1
Bear Lake-COST 1
Bear Lake-outcrop
Milky River-COST 1
Pyrolyzed HC (S2) vs TOCTrue Average
Hydrogen Index
Restricted
Data Range
(no coals)
-155.44
-155.43
-155.42
-155.41
-155.40
-155.39
-155.38
-155.37
-155.36
-155.35
-155.34
0.01 0.10 1.00 10.00
Total Organic Carbon
0 500 1000
Hydrogen Index
Kialagvik
Kamishak
Longitude
(u
p-s
ecti
on
)
Typ
e I
Typ
e II
Typ
e II-
III
Typ
e III
co
als
so
urc
e
no
n-s
ourc
e
biostromal facies
Variation by Stratigraphic PositionKamishak and Kialagvik Fms, Puale Bay
Milky
River
Bear
Lake
Unga eq
Quat
Ste
po
va
kTo
lsto
i
Lean Elev Coal Gas-Prone Oil-ProneGas-
Cond Imm
Oil &
Assoc
Gas
Gas
North Aleutian Shelf COST #1
Geochemical Profile
TOC HI Ro
Sherwood and others, 2006 (MMS)
NAS COST 1 Vitrinite Reflectance
Conclusions
Puale Bay Mesozoic units include highly oil-
prone source rocks • Upper Triassic Kamishak Fm: especially brown-gray
micritic limestone facies (avg HI = 745 mg/g)
• Middle Jurassic Kialagvik Fm: lower part, fissile dark
gray siltstone facies (avg HI = 654 mg/g)
NAS COST 1 well Cenozoic units are coaly &
dominantly gas-prone, minor liquid-prone
coals?• Eocene Tolstoi Fm: (avg HI = 319 mg/g)
• Eo-Oligocene Stepovak Fm: (avg HI = 167 mg/g)
• Miocene Bear Lake (avg HI = 123 mg/g)
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